INTRODUCTION

This is a general outline of the process for a basic annual-maintenance varnish job. Healthy, well-maintained exterior varnished surfaces will require one maintenance coat per year, unless the boat is in a boathouse or under cover. Additional coats might be needed on surfaces subjected to high traffic, abrasion, or ultraviolet exposure, and more frequent recoating might be needed in the tropics.

In areas where damage requires touch-up varnishing of bare wood, or if starting a varnish project from bare wood, I apply nine coats of varnish minimum (seven coats on interior surfaces). On transoms, masts, or deep-grained oak, I recommend a minimum of 12 coats. 

Note that with any exterior varnish, you may need additives to keep your varnish flowing in hot sun, windy weather, or on particularly large expanses of wood. Conversely, when varnishing off-season in cold shop or storage spaces, you may require additives to help your varnish dry.

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TOOLS:

• Power sander with a hole-punch pad and adaptor to fit a standard vacuum hose.
• Vacuum with brush and floor attachments
• Extension cord with two-way splitter
• Heat gun fitted with nozzle ends
• Scrapers (I use carbide ¼”, ¾” triangle blade, 1½” blade.)
• Hard and soft sanding blocks plus small wood blocks for fairing touch-ups
• Rubber mallet
• Screwdrivers (square, slot, and Phillips-head)
• Long awl (to unseal thinner and additive containers, clean caulk nozzles, and poke drain holes in varnish cans)
• Paint-can opener key
• Five-gallon bucket
• Varnish brushes (I use Redtree badger-hair brushes, and 1” (25mm foam brushes for a few limited instances.)
• Varnish roller trays (I use white plastic trays with a bubbled surface; they can be reused if cleaned well.)
• Roller frames and foam rollers (I use yellow foam rollers: 3” (76mm) for small jobs, 7” (178mm) for large surfaces.)
• Sharpie pen for labeling
• Tack rags and rags (and scissors to cut them)
• Rubber gloves, eye protection, dust masks, respirator, ear protection, knee pads, and protective tape for fingers 
• Cone paint filters and a filter “donut” (a plywood or cardboard cutout with a 4” [102mm] hole to hold the filter over a bucket)
• Stir sticks
• Brush spinner and combs
• Two plastic buckets with lids (2 qt [2 liter]) for cleaning brushes, and a 1 qt [one liter] to hold brushes)
• Jug labeled “Used Thinner” 
• Umbrellas (to shade my varnish tray as I work)

MATERIALS:

• Sandpaper—80 grit, 120 grit, 240 grit, and sticky-back 240-grit sheets (Use quality sandpaper such as Norton. It’s worth it.)
• Red Scotch-Brite scouring pads. Half a pad fits on a ¼-sheet sander (for deglossing only).
• Tape (I use 3M Scotch green masking tape #256—for exterior use up to five days— and 3M blue 2090 tape for bare wood and double-taping around touch-ups for heat-gunning.)
• Denatured alcohol in a spray bottle
• Turpentine
• Varnish and additives 
• Scrap cardboard and boxes (for under buckets and for workstation)

PREPARATION:

• Wash the boat. This removes grime and saves sandpaper.
• When removing hardware that would interfere with your varnishing, label each piece for re-installing afterward. For any hardware you leave in place, be sure to tape it thoroughly to prevent contamination with splatter or stray varnish.
• Identify and mark with tape any damaged or blistered areas that require touch-ups. (When you find “blown” varnish, that is, varnish that has turned yellow and milky, and no longer adheres to the wood, think about why it’s blown—sun, moisture—and fix the source of the problem if you can.) Deal with these areas first, because they will need nine coats to match the surrounding varnish. Remove blown varnish with a heat gun and scraper, scraping into the damaged or bare spot (see more in TIPS AND DETAILS, below). Fair the edge of intact varnish into the bare spot with 120-grit paper on a small hard block until smooth. Sand the entire touch-up area with 240-grit paper. Wipe with alcohol and seal with a 50/50 varnish-and-turpentine mix. Do this with each touch-up. 

Dieter Loibner

Tape off with a double layer of blue 3M tape and carefully remove blown varnish with a heat gun and scraper.

• Tape will not stick to sanding dust, so before sanding it’s best to tape off the surface to be varnished, and be very careful not to disturb the tape while you sand. If sanding up against glass in portlights, hatches, or windshields, it’s best to tape first just for insurance; scratches in glass often cannot be undone.

• When touch-ups are sealed and you’re building coats on them, you can begin to sand areas with intact varnish. On sunny days, you can get two or three coats of varnish on touch-ups if they dry enough to the touch in between; on cold days, you may get only one on. 

Dieter Loibner

Fair the edge of intact varnish with 120-grit paper, and then switch to 240-grit to sand the entire touch-up area.

• For surface preparation of healthy varnish, it’s important to degloss everything. I start with 240-grit paper on a ¼-sheet palm sander to do a quick deglossing and overall sanding. It does the bulk of the work quickly and easily. Then I hand-sand using a soft block with sticky-back 240 grit to remove swirls from the mechanical sander and hit any missed spots such as seams and corners. For surfaces with prominent brush strokes or uneven varnish, it’s best to hand-sand with a hard block to fair them. For deglossing line holes, detailed scroll pieces, or hard-to-reach undersides of cleats, Scotch-Brite scouring pads work well, but they will not remove sags, drips, or hairs. 

Dieter Loibner

Degloss with 240-grit paper on a 1⁄4-sheet palm sander connected to a shop vacuum, and then handsand with a soft block to remove swirls.

• Work around your wet touch-ups. If you need to, skip the midday touch-up coating so you can sand parts near touch-ups without the dust embedding in very wet varnish. Usually after a couple of hours, touch-ups are dry enough to sand nearby them without them becoming embedded with dust. 
• If you’re doing more than one overall coat, sand everything out, and apply your first full coat as soon as you can, rather than wait until all your touch-ups are done. This allows your first overall coat a few days to dry before sanding for the topcoat once your touch-ups are ready. (If only doing one overall coat, you’ll need to wait until your touch-ups have eight coats on them before doing your finish coat on everything.) 

Dieter Loibner

Wet-sand in dust-sensitive areas, e.g., to wet varnish. The specially formulated paper cuts faster than dry sandpaper.

• Wet-sanding, which produces no dust, is useful when you need to sand a surface next to wet varnish or touch-ups. It’s also useful when prepping any exposed exterior varnish when you shouldn’t produce dust or you don’t have power for vacuuming. Specially formulated paper for wet sanding cuts much faster than conventional dry sandpaper. I use it with a 2-qt bucket of water and a microfiber cloth, sprinkling water on my sanding area with my fingers or dipping the paper in water before sanding a section. Then I wipe the wet dust slush off with my wrung-out cloth. Leave the bucket of sludge water in the sun to evaporate. Do not dump it at the shop or marina. Dry wiping and vacuuming aren’t necessary. Just wipe the surface with alcohol, tack, and varnish.

Dieter Loibner

Dip your fingers in a small bucket of water to dampen the area, or dip the wet-sand paper. Afterward, clean up the area with a microfiber cloth.

• After dry-sanding, wipe down with a dry rag. When the rag gets too full of dust, I clean it by letting the vacuum hose suck it in while I hold the end. Next, vacuum to clean any leftover dust off the surface and surrounding areas, and then wipe down the surface with a clean rag and denatured alcohol. I put alcohol in a spray bottle for economy and convenience. 

Dieter Loibner

After dry-sanding, wipe down and vacuum the surface and surrounding areas. Then spray with denatured alcohol and wipe again with a clean rag.

• If you didn’t tape off the perimeters of the surface to be varnished before sanding, do it now. 

APPLICATION:

• Just before varnishing, wipe the surface with alcohol again, and then tack with an unfolded gauzy tack cloth to pick up any last bit of dust. Wear gloves to keep the tack cloth wax off your hands, and never press a tack cloth hard against the surface (it will leave wax, and your varnish will fish-eye and not adhere). If varnishing interior surfaces the same day you sanded, it’s best to spray the air above with a mist of alcohol to drop any airborne dust and then wipe surfaces with alcohol. Also wipe any work lamps you may have positioned over your varnish. Pull your hair back and mind your clothes. A wool sweater or any cloth that sheds fibers isn’t good varnishing attire. I roll and tip my varnish. 

Dieter Loibner

For final prep, gently wipe with an unfolded gauzy tack cloth. Wear gloves and never press a tack cloth hard against the surface, as it will leave wax.

• For most surfaces I use a 3” yellow foam roller with a white plastic bubbled tray. The roller should be flaked to remove lint from it, and its cardboard ends should be rubbed—even if the packaging declares “NO LINT” in big bold letters. The roller puts the varnish on quickly and evenly. First, I roll the varnish on in short sections—roughly 1.5’ x 2’ (0.45m x 0.61m). Next, using a high-quality badger-hair brush, I brush the rolled varnish gently forward, then brush it back into the finished section and move on. This sequence helps reduce the stop-and-go buildup lines and keeps the varnish flowing into itself.

Dieter Loibner

Brush rolled varnish forward, and then back into the finished section. This helps reduce buildup lines and keeps the varnish flowing.

• If I have a large expanse to varnish or if it’s breezy, it’s helpful to add a little flowing agent, such as Epifanes Easy-Flow or Penetrol. But if it’s not breezy and the expanse is not large, I use the varnish straight out of can, without any I hardly ever use thinner in varnish. The exception is when I’m coating a large expanse, such as a hull, on a windy day.
• When varnishing caprails or cabin trim, I first roll the underside edges just up to the visible round, and tip with a foam brush, which leaves a nice beveled edge to meet up with when I come back and tip the adjacent visible surfaces with my varnish brush. This sequence keeps me from having to slow down to get those unseen spots and break my flow on the visible surface. With the undersides done, I’ll quickly coat the sides first, then the top for a short length—roughly 1.5’ x 2’—then move on to next section.
• As I varnish, I keep my varnish tray in a cardboard produce box with a magnetic clip on the side to hold my brush. I also keep a rag and my tack cloth in the box in case I need them as I’m going along. 
• It’s important to block the sun from shining on the tray of varnish. The box flaps can help with that, but I also use my own shadow, shadows from the boat, or umbrellas I set up strategically.

Dieter Loibner

Protect varnish from the sun by putting the container into a high-sided box. If necessary, you can make your own shade with a small umbrella.

• When you’re finished applying varnish, go back around, and, while it’s still wet, clean up any varnish you may have gotten where you don’t want it.

CLEANUP:

• Pour leftover varnish into a separate can from your fresh varnish. 

Dieter Loibner

Use paint filters and a filter “donut”—a plywood or cardboard cutout with a 4″ (102mm) hole to hold the filter over a bucket.

• If you clean your bubbled tray well with your brush, you can let the tray dry and reuse it. 
• Pour a couple of inches (about 50 mm) of turpentine into a 2-qt plastic bucket, and then discard the used yellow roller, but put the roller frame in the bucket and clean it well using your brush. Wipe the frame with a rag, and put it away. (If you don’t clean your frame, it won’t roll next time you need it.) 

Dieter Loibner

To reduce expenses, maintain all your brushes well.
Cleaning them with a brush comb and turpentine is only the first step.

• Clean your brush well with a brush comb and turpentine, and spin any solvent lingering in the bristles into a 5-gal pail with a brush spinner. If you use your brush frequently, after cleaning it you can store it in a quart plastic bucket with 1” or 2” of turpentine. Cut a slit in a plastic lid to push the handle through. Then each time you need to use it, you just comb it out and spin it, and you’re ready to go. 

Dieter Loibner

Next, mount the handle to a brush spinner and spin hard into a 5-gal pail to remove all the remaining solvent from the bristles.

• I keep a lid on the 2-qt cleaning turpentine bucket and reuse it for quick cleaning of my brush through the day, or for setting my brush in while going for lunch. (Leave your brush in turpentine only. In paint thinner or mineral spirits, varnish in the brush will turn to goo in just an hour.) When the cleaning turpentine gets too murky, pour it into a labeled “Used Turpentine” container, and take it to a hazardous waste disposal facility when it is full.

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TIPS AND DETAILS:

• When spot-stripping varnish, use a heat gun set on medium and fitted with a narrow nozzle to help keep varnish from bubbling up adjacent to the intended touch-up. Double-taping with 3M blue 2090 tape right around your touch-up will also help limit the area you strip. And remember, you need only a bit of heat on the varnish. It doesn’t need to be a gooey mess before scraping.

Dieter Loibner

To spot-strip varnish, use a heat gun set on medium with a narrow nozzle to direct the heat and keep adjacent varnish from bubbling up.

• When applying touch-up varnish, always brush in toward the patched area to reduce buildup on the edges surrounding it. This makes for easier sanding when your many repair coats are done.
• Never let more than three coats of varnish dry before pulling your tape. When doing nine coats, I’ll pull my tape after the fourth coat before it’s dry, then again after the eighth coat before it’s dry. I always retape just before the topcoat.

Dieter Loibner

A double layer of 3M blue 2090 tape limits the strip area. Never let more than three coats of varnish dry before pulling the tape.

• For sanding and varnishing bare wood, I will sand up to only 120 grit and then seal with 50/50 varnish and turpentine.
• “Hot-coating” is recoating within 24 hours of the prior application, before that coat has completely cured but is dry enough to rub your hand over. When hot-coating or recoating without sanding, tack between each coat. To keep the surface fair, it’s best to let the varnish thoroughly cure after three hot coats, and then sand it, especially on open-grain teak or whenever the finish shows too many brush strokes or any unevenness. 
• Don’t pile more varnish on top of flaws. Spot-sand out any sags, drips, hairs, or bugs before applying the next coat. If you have a thick drip or sag, get rid of it before the next coat—scrape it down with your scraper, let it dry, then sand it out. In the meantime, just varnish around it.
• When taping around curves, use a series of small pieces.

Dieter Loibner

Taping around curves is tricky, but a series of small pieces going in the same direction will make it easy to pull the tape after the job.

• Be aware that sanded surfaces—whether they are to be painted or varnished—will usually pull adhesive from your tape and leave it on the surface. It’s hard to see this residue, so always double check for it and clean it away before varnishing or painting that area. It will otherwise show up in your finish.
• Never pool varnish in corners or on low horizontal seams. It tends to blow within a year.
• Dip only your brush tip into varnish, and never hold your brush upside down long enough to let varnish get in under the ferrule.
• When you set your brush in turpentine, you need the solvent to come only an inch or so up the bristles. Don’t immerse your brush up to the ferrule in turpentine.
• Be mindful of sharp tools in your pockets as you move about the boat; also beware of any metal snaps, rivets, and buckles on your clothing that could scratch the finish. 
• Wear a dust mask for dust, a respirator for chemicals (keep respirators in sealed bags for longer life), gloves for wipe-down and cleanup, and kneepads. 

Dieter Loibner

Dust mask, respirator (with replacement filters), gloves, kneepads, and tape (to protect fingertips) are the basic necessities for personal protection.

• While gloves are important when handling solvents, I never wear them while varnishing. It’s too easy to get varnish on the tips of the gloves’ fingers without realizing it, and then to go around the boat leaving little varnish prints everywhere.
• Always put lids back on tight each time you use anything.
• Be especially careful with your rags. Always hang them to dry or put them in a fireproof bucket with water in it. Never leave a chemical rag balled up or resting on varnish. 
• Unplug your heat gun whenever you turn your back on it, and be mindful of how and where you set it down when it’s hot.  
• Check for residual adhesive after pulling your tape when the job is done. Rubbing a dirty hand or rag over where it was will make the adhesive show. Clean away the adhesive with an orange citrus cleaner if you need to. Do not use an acetone-based cleaner.
• In a cold shop in the winter, I sometimes add accelerator to speed up the drying time so that I can coat the next day. (It’s also good to slightly hasten drying time if rain is on the way.)
• Random-orbital sanders can be problematic with varnish. For the most part, they are overkill. You must be very careful not to create circular ditches and ruin the fairness of the finished surface. It won’t show up until you put the glossy finish on. Also, the friction created by sanding at high speeds with paper as fine as 320 can heat up and lift the varnish. 
• To make unfolding cold tack cloths easier, just set them in the sun or on a lamp for a minute.

Keep it flowing smooth, shiny, and bright! 

May the flow be with you.

Joni Blanchard is the owner of Leatherwood Finishing Company and the author of Tricks, Cheating, & Chingaderos: A Collection of Knowledge and Tips for Varnishing/Painting Wooden Boats.

↵ Return to 2022 Fitting Out Guide Table of Contents

Dawn came early, as it so often does when one is anxious, and I was anxious. The forecast was for a hot and sunny day, a rare treat in our corner of the Pacific Northwest. Normally I would be elated at such a prediction, a chance to slow down, go for a lazy sail, or putter about the boat. But this was painting day, and, next to snow, intense heat was about the worst weather we could be dealt; it would cause the paint to dry too fast, thus leaving brush marks, sags, and lap lines where the so-called “wet edge”—the advancing front of fresh paint—was lost. We had spent days painstakingly sanding the hull with a longboard. Our arms hurt. Our backs hurt. Our heads hurt—probably from self-medicating our arms and back with contents from the cooler. It would take another day of cleaning and taping, but it would all be worth it if we could apply a perfect coat of paint.

Staging surrounded the boat, laid out so we could walk continuously down the length of each side without stopping or tripping. In a shady spot, we had laid out our paint, thinners, rags, extra brushes and rollers, and anything we might need in a hurry. The plan was for an early start. We wanted to dry off the dew, get the hull wiped down, and be painting as soon as possible so as to take advantage of the cool morning air. Three of us mixed up our paint, grabbed our tools of choice, and went for it—one person rolling, another “tipping” the rolled-on paint with a brush, and the third standing by to pour more paint when we ran out and look for holidays, runs, and sags. And, most important, this third person also adjusted the viscosity of the paint as we went along; we would call out to have brushing thinner added as the sun evaporated it out of the paint pot, or to further thin the paint as the day heated up, to assure that the paint would flow out and level off. Although we didn’t get a ticker-tape parade when we were done, we were pretty proud of the finished product.

By noon that day it was hot, and the wind had picked up. As we were cleaning up, we heard shouts of anger from somewhere in the boatyard. A bit of investigation revealed a jet-black boat practically spontaneously combusting in the heat of the day and her crew doing everything they could to hopelessly trowel on a decent paint job. It was a losing battle, but they were not giving up. They should have. I’m pretty sure at one point I saw a paintbrush stick to the side like a kindergartener’s macaroni-art project, and the conditions did not improve with time.

This article is about how to get your paint to flow and level. And the first thing you can do to assure success— before adding stuff to your paint, and before refining your application technique—is to pick the proper weather.

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PICKING YOUR WEATHER

Hot Weather

Have you ever read this on the label of a paint can: “Do not apply in direct sunlight,” and wondered, “why not?” In direct sunlight on a warm day, say over 75°F, a white finish can reach temperatures of 180°F degrees and black can reach 250°F. With those temperatures, not only are the solvents quickly leaving the paint, but the outer layer of paint is oxidizing (drying) too quickly, and locking the brush marks in place. There simply is no way for the paint to level—to smooth out once it is applied to the surface—let alone maintain a wet edge.

Perhaps you’ve heard the suggestion of putting your can of paint in the refrigerator until you are ready to paint. Don’t forget that the temperature of the surface to be painted is just as important as the air temperature and the temperature of the paint. So, if you are spread- ing your refrigerated paint in hot air on a boat that has been sitting in the sun, your problems will persist: as soon as the paint is exposed to the hot air and applied to the hot surface of the boat, the solvents are going to flash off, the outer layer is going to heat up and start to dry, and you’ll be left with paint that won’t flow out. The solution is simple, and right there on the label of the can: Do not apply in direct sunlight.

So, check the weather forecast. If it looks as if it is going to be hot on the day you plan to paint, prep the boat the day before so that all it needs the next morning is a quick wipe-down before painting. I often see people spend the morning preparing a boat and then painting in the hot afternoon sun and getting a poor paint job that has to be redone. Save yourself the trouble: prep one day and paint the next.

Cold Weather

“That’s all fine and dandy” you say, “but what about when it’s cold and wet?” Well, when I am cold and wet, I have a tendency to huddle up and hold myself for warmth. Paint has the same tendency: it thickens up, it doesn’t like to flow out, and it can feel as if you are trying to spread glue with a cat’s tail. Again, just as important as the outside temperature and the temperature of the paint is the temperature of the thing you are painting—the substrate temperature. Often, the substrate is much colder than the air in the morning, and it might warm up if direct sunlight beats down on it. But if you are working in a part of the world where mornings are cold and afternoons warm, you won’t find much time where the substrate is the same temperature as the paint. In this case, you must first warm things to a workable and even temperature, preferably around 55°F.

If you are lucky, your boat is in a shed or building with a woodstove or some other heating device. If not, grab some tarps and build a quick temporary shelter, then find a way to get some heat going, such as a blast furnace or safety heater. Sometimes a 500-watt halogen work light does the trick (if you decide to use a propane blast furnace, remember: they put out a lot of moisture). If your paint is still sitting in the refrigerator, take it out the night before and put it someplace warm. Do the same for the thinners and conditioners you plan to use, as well, warming them to just above room temperature but being careful to not bring them to the point at which they will ignite. Some of us have a long drive to the boatyard; for me, it’s an hour and a half. I like to put the paint on the floor of the car under the heater and keep the heat going. You will likely have to warm it up again before you start mixing and painting, but at least you won’t be starting with really cold paint.

Painting your boat without a shelter in cold and wet weather, such as spring or fall, can be challenging, but rest assured it’s possible. You likely won’t get as much done every day, so plan to be hauled out longer than you might expect if you are in an area where your boat lives in the water year-round and you haul it just for painting and bottom maintenance. Break up your painting projects so you are not trying to paint everything in one or two days. Start painting late in the day to take advantage of sunlight. And be careful: even in a cold region, direct sun can still heat up the substrate quickly.

WoodenBoat School

Painting a boat in warm or cold weather requires careful use of modifiers that allow the paint to flow and level. Shelter can make a big difference, too, in blocking sunlight, retaining heat, and protecting from wind and dew. The first step to assuring a good paint job is to choose your weather.

Thinning and Conditioning the Paint

Have you ever thrown up your arms in disgust and screamed at the heavens, “Why can’t the manufacturer just make a paint that I can use straight out of the can!”? There are too many factors at play for such a one-size-fits-all approach. In order to evaluate coatings, tests in the lab must be consistent, so paints are formulated to standards. For example, an oil-based alkyd is said to be dry after cooking at 70°F for seven days. But in the real world, where you might have daytime temperatures in the 80s and nighttime temperatures in the 50s—or 55°F consistently, all the time—the paint might take a month to fully dry.

Flow and level are also both calculated in the lab, and the recipe is adjusted for optimum performance. The application method is a factor because different qualities are preferred if you are spraying as opposed to brushing. To evaluate flow and level, a lab will take measurements using a sag meter and a leveling bar. These are metal tools with precise grooves cut in them, and when they are dragged across a paint film they’ll show what thickness of paint will flow out and level. Various modifiers or additives are mixed into the paint until the chemist is satisfied with the results. Sometimes they want to make the paint thicker, reducing flow so you can get a thicker coat applied before sags appear; sometimes they might put in a surface modifier that alters the sur- face tension so the paint levels off better than it would otherwise. Regardless of what’s done in the lab, however, you most likely will have to adjust the paint on the day you use it, to get it to flow out and level off according to the ambient conditions.

To combat the effects of excessive ambient heat, you can thin the paint with a suitable solvent. The instructions on the labels of quality paints include suggestions for suitable solvents; some blends, such as Interlux 333, are formulated specifically for brushing. If you can, thin with a solvent that has a slow evaporation point or use a paint conditioner designed for thinning a paint in hot conditions. Typical paint conditioners are a blend of oils and sometimes resins and other additives. Penetrol is a popular one. They can drastically increase the paint’s dry time and wet edge, but because they are usually mostly oil, they can soften the dried paint film; sometimes dull the gloss; and, if not mixed in well with your semigloss, satin, or flat-sheen paint, can yield a mottled look. With as little as one percent by weight of raw linseed oil added into the paint, you will notice a big difference in the paint’s softness, dry time, and durability.

Be careful when adding thinner, too. Too much of it will dilute the paint’s resin, and you will be painting on mostly solvent and pigment, resulting in poor film build and a loss of gloss. This starts to happen when the additional solvent reaches 20–30 percent of the paint volume. In most single-part paints, the solids content is around 50 percent, meaning that half of the paint is resin and pigments while the other half is solvent. An additional 30 percent solvent diminishes the solids content; you would thus have to apply additional coats to get the film thickness you would get with one unadulterated coat. However, if that is what it takes to get the paint to flow out in the conditions you are stuck with, it might be the better option.

When mixing thinners and conditioners for warm weather, the goal is to keep the paint from drying too quickly. With cold weather, the goal is to speed up the paint’s drying so it doesn’t thicken due to the cold and cause sags, runs, and brush marks. If there is a lot of wind, don’t paint! If you disregard this advice, treat the paint as you would for warm weather.

Use the same additives for cold weather that you use for warm weather, except that instead of a slow-evaporating thinner you might try a quick one. Some- times, if I am afraid the substrate might be a little cold and not want to hold onto the new paint, I’ll even add a little bit of a “hot” solvent to help melt the old layer of paint and thus help the new one adhere. When the weather is cold, roll or brush the paint on thin; on such days, it takes a long time for paint to “through- dry”; if you have applied a heavy coat, you might notice weeks later that even though the outside is hard and sandable, you can easily press hard and leave a mark. Resist the urge, in cold weather, to apply multiple coats of paint before the previous coat has thoroughly dried, or you will end up with a soft mess.

Photos by Peter Marshall

Topside enamel is seldom applied without the use of additives, and the choice of additives depends upon the weather and the viscosity of the paint in the can. Left—Penetrol improves flow, reduces brush marks, and extends the working time of the paint; too much of it will soften the cured finish. Middle—Some solvents, such as Interlux 333, dry slowly and are meant for hot weather. Right—Xylene is a “hot,” or fast-evaporating solvent, and is ideal for cold-weather painting. It should be used sparingly, and the mixture checked on a test board, because it can melt paint.

TOOLS AND TECHNIQUES

Conditioning the paint is only one of the variables of a good paint job; tools and techniques are also critical to ensuring good flow and leveling when applying paint.

Before you begin painting, make a test board. This could be a simple piece of plywood, 2′ × 2′ or larger. It need not be fancy. Every phase of your painting project should be tested on this board. Use it to test how your paint is flowing out before you apply it to your boat; this way, you can see if you need to add more conditioner or less, or not paint at all. It’s much cheaper and easier to not paint than to do a bad job painting and have to sand it all off.

Starting with the primer coat, a foam roller tends to work the best for applying paint. Primers do not flow out or level because they are packed full of pigments that do things like hide the previous layer, block tannins, and fill grain. Don’t attempt to tip out the primer; the stipple from the foam roller leaves a very nice and even surface that is easy to sand out. If you try to use a brush to tip off the primer, you will get brush marks that are uneven, making it harder to sand out and giving a greater loss of the primer layer. This translates into more work.

There are two basic types of foam roller: the yellow ones that fit a standard roller frame, and the little white ones with domed ends that take a special frame. I had never seen the little white ones until I was working on a 175-million-dollar-yacht and the varnish crew used them exclusively. After I promised to never reveal their secret (sorry, guys), they informed me that the little white rollers left a finer stipple, giving a smoother finish. I tried them. The varnish guys were right, but the downside is these rollers come only in short lengths, inadequate for a large surface. The yellow foam rollers come in three sizes and fit standard roller frames. After doing an amazing job of priming, make sure you sand out all of the stipple. To do this, employ a friend and a raking light—that is, a light held at an angle to the surface—to make sure it’s all smooth. Any leftover stipple will telegraph through the top coat. The primer coat is the spongy, cozy layer of forgiveness that helps you even out the surface of the boat; its surface should be oh-so-smooth.

Photos by Peter Marshall

Rolling and tipping of topside paint has become standard practice, and the choice of roller cover is critical to a good job. Left—Standard-sized foam rollers are an ideal choice for large surfaces. Right—Small, white, dome-tipped foam rollers are reportedly superior.

The topcoat allows you to really get to show off your talents as a painter. If you must thin the paint, it may take a couple of final coats to completely hide the primer; “hide” is not only a function of pigment load, but also of coat thickness. I like to roll-and-tip my top coats. It’s fast; an experienced and prepared painter, working with a friend, can paint a properly prepared 30′ sailboat in 30 minutes.

We have talked about roller choices, but what should we tip off with? Don’t even think about using a cheap brush if you want a great job. Here are the basics of brush design: The bristles of a great brush will have “split ends,” which means one bristle is broken at the end to form many smaller bristles. The smaller the bristle, the shallower the groove it leaves in the paint and the less the paint has to level out to eliminate the brush marks. Put the brush in your hands and run your fingers through it to make sure the bristles are fairly even in thickness, which translates to even grooves in the paint film, and thus consistent leveling.

Another trait of a great brush is the shape of the tip of the brush. An inexpensive brush’s tip will be fairly flat, having only spilt ends at its very tip; a great brush will have a tapered crown and the split ends are distributed along the portion of the brush you actually use.

The brush should be packed with enough bristles to hold paint, and it should be stiff enough to move paint around—but not so stiff that it is not flexible. For small jobs you can buy, for a couple of bucks each, some decent artist’s brushes in the range of 1⁄2″ to 1″, but they are pretty flexible. Try one out; if it is too flexible, shorten the bristle length by wrapping some masking tape around the bristles until it firms up. My shop has a painting corner in it, which is a fancy way of saying my shop has a place where I lazily heap my painting supplies, and in that corner I try to keep a supply of inexpensive foam brushes. In numerous books, I have read about glorious jobs produced with foam brushes, but I have never been able to get a great paint job with one. If you look closely at the tip of a foam brush, you will see just how ragged they are. This hinders leveling. When I use them, foam brushes tend to act like squeegees, pushing the paint clean out of the way. So, why do I keep them? They are great for touch-ups.

Photos by Peter Marshall

The rolled-on paint must be brushed, or “tipped,” to spread it evenly and to begin its leveling, and a good brush must be employed for this purpose. Left—Great brushes have bristles with split ends, and the tips of the brushes are beveled to ensure maximum contact of bristle tips with the paint. Right—Poor brushes have squared-off tips and cheap bristles that shed during use.

You can successfully roll-and-tip on your own, but if you have a team of two to four people, you will get a better job. Use one person to roll, one to tip, one to mix paint and pour it in the tray (this way you don’t have to stop painting and risk losing your wet edge), and one to look for holidays, sags, and runs. Remember to constantly communicate with each other by saying things such as “more paint here,” or “less paint, roll it out thinner,” or “needs more conditioning so add three capfuls of thinner,” and so on. Yes, this is why shiny boats tend to cost more. It takes more people to keep them that way.

If you are more old-school and decide to forgo the roller and use only a brush, you can get good, even results by painting first in alternating diagonal lines (like painting an X) and then tipping out. It’s important when you tip out to follow the sheer when painting plywood or the plank lines when painting a planked boat. No matter how good you are, there will be brush marks, but if they follow the sheer or the plank lines (as opposed to random zigzags like the ones on Charlie Brown’s shirt) they tend to disappear.

Recently a friend asked if I would help him paint a new boat he was building. He was using a two-part top-coat paint that I had never used. Two-part paints can be tricky. They are used mainly on big, expensive yachts and airplanes, and generally are formulated for spraying rather than brushing. That means the paint is sticky, goes on very thin, and dries fast, not leaving much time for leveling out. Some manufacturers make brushing thinners for these paints, but that does not always help to the extent you would like it to. This is where that sample board can really come in handy: make sure you practice on it before touching a brush to the actual project.

We mixed our paint according to the directions, but as soon as I touched the sample board with the brush I realized we were going to have problems because the brush seemed to drag, sticking to the surface even though the paint was fairly thin. We added more brushing thinner and continued to add it as we went along the boat and the thinners flashed out of the paint pan. We ended up with a decent job. Some two-part paints claim you can buff them out with an electric polisher, and some claim you can’t; buffing allows your sins to be erased by a machine later on.

If you are a novice, afraid of making a mistake and worried your paint job won’t look like a calendar photo, or if you are the experienced veteran who rushed the job to satisfy a schedule, I have some final words of advice for you: Don’t worry about it. It’s just paint. You will be doing it again next year anyway.

Nonskid Deck

My first experience painting a nonskid deck came when I was just a little kid. At 36′, my parents’ old converted fishing troller was not a large boat, but its after portion was a giant party deck above the old fish hold. It was covered in nonskid.

One day, my dad decided to repaint the deck, so he got out the TSP (trisodium phosphate) and mixed it in a bucket of water, explaining to me that TSP didn’t leave a residue so it was good for cleaning paint work before painting. On that deck, the nonskid was silica sand scattered (broadcast) over wet paint and let to dry. Then the excess nonskid was vacuumed up and a top coat was applied. As I watched him scrub, he explained to me that with this method you can’t sand to any effect when you go to prep for a fresh coat of paint, so you must clean well!

Today, several different kinds of nonskid are available, including ready-made and mixed varieties, thick paints that dry rough, and various different sands that you can either stir into the paint before application or apply using the broadcast method while the painted coat is still wet. When using the broadcast method, or if you are adding nonskid particles to the paint pot yourself, you have a few options not only for the particle material but also its size.

The pre-mixed, ready-made, nonskid paints are often available in professional industrial-grade, two-part systems consisting of resin that you mix with a catalyst when you are ready to paint. There are also easier-to-handle single-part systems. The benefits of these premixed products are twofold: first, they create less mess, and, second, you don’t have to apply a top coat after application. If there is a downside, I would say the industrial stuff is expensive and the single-part versions tend to be light on concentration of nonskid particles.

Photos by Peter Marshall

Major paint manufacturers offer fine, uniform-grain sand additives to create nonskid paint of virtually any color.

A fairly new development in the world of nonskid is paint formulated to be thick. This type tends to be a water-based acrylic that goes down thick and is then hit with a textured roller to create an aggressive nonskid surface. Although simple to use, they dry very fast; one should plan accordingly. I found out the hard way to be very careful not to use, or spill, harsh chemicals such as gasoline or acetone on these surfaces; these chemicals will “melt” or dissolve the acrylic coating. Acrylics don’t cure like alkyds or epoxies; they get hard once the solvent is gone, but reintroducing the solvent makes them liquid again, the way shellac handles. If you want a version of this but need it to be more robust, try a two-part epoxy or epoxy paint, then add silica adhesive thickener to it until it is really thick—almost like cookie dough. Then spread it on and use a textured roller to achieve the desired surface. Years ago, I worked in the movie industry, and this was a method the painters used for giving texture to movie-set pieces.

Proven by decades of trial and error, the old method of broadcasting grit into wet paint is a workhorse of nonskid applications. You get a lot of flexibility using this method because you can choose not only the type of nonskid particles but also their size and concentration. Some examples of materials are walnut shells, aluminum oxide sand, silica sand, and rubber sand. This flexibility allows you to have more aggressive nonskid in areas such as the foredeck around the anchor windlass or the cockpit sole, and less aggressive texture in areas such as the cabintop or a place you might sit.

Photo by Peter Marshall

Rubber particles offer a softer surface than sand does.

Start by laying a coat of your deck color in the area you want the nonskid to be, then either put your particles in a shaker and shake them over the wet paint or simply toss or cast them onto the wet paint. Start light. You can always add more if you don’t think it looks even or aggressive enough. Let the paint dry. Then get a broom or vacuum and clean up any loose particles. After that, put down another coat of deck color. When you need to refresh the paint, scrub and clean it well with a soap that does not leave a residue (such as TSP), and recoat. When the nonskid starts to fill in with paint, grind it off and do it again.

All nonskid is difficult to clean and keep clean, so my philosophy is to use it only where you need it. Keep the nonskid out from under cleat horns, for example, because it can chafe lines. A nice way of laying out the different zones of nonskid on your boat is to use masking tape and create waterways (smooth areas of paint without nonskid) around deck fittings, cabin sides, coamings, and toerails. If you are having trouble visualizing this, go check out any fiberglass boat and you will see areas where the molded nonskid is and is not. Deciding on the width of the waterways is artist’s choice, and it depends on the size of the boat and size of the area to be painted. A 2″-wide waterway on a small daysailer might look silly and wide, but on a 75′ yacht it might be just right. Use your eye as your guide, but don’t sacrifice safety for beauty.

Photos by Peter marshall

Step 1: Nonskid application begins with a cleaning or sanding of the surface to be painted, and then careful masking around hardware and deck furniture. Step 2: Detailing the masking tape with radiused corners, marked with the gauge shown in Step 1, is important for a refined appearance. Step 3: The paint is applied to the masked-off area. Step 4a: The nonskid medium is then broadcast by one of several means. Here, a modified Ball jar does the job.

Waterways look best to me when they terminate in a radius. This is more forgiving to the eye and allows your dimensions to require less precision. To get those radii consistent, I like to make a radius gauge block out of 1⁄4″ doorskin. Generally, I make two blocks, each about 2″ square, one with different outside radii on each corner and one with different inside radii on each corner. You make whatever fits your project. A nickel or a quarter works well for drawing the radii. Using a Forstner bit or a paddle bit in a drill press can help you make the inside radii on your gauge block perfect. To do this, draw your gauge on an oversized piece of pattern stock, then at each corner drill an appropriate-sized hole. With the holes drilled, cut the block to the finished size. This is a lot easier than trying to get a drill bit to drill half on the plywood and half off.

Photos by Peter Marshall

Step 4b: Particles may also simply be broadcast by hand. Step 5: Excess nonskid is vacuumed from the surface after the paint has dried. Step 6: A second coat of paint covers the particles and completes the job. 
The nonskid surface, with masking removed. Maintenance coats should be applied sparingly, in order to retain the effectiveness of the nonskid. Surface preparation should be an aggressive scrub with trisodium phosphate—unless one wishes to sand it all off and start over.

Peter Marshall is the founder and proprietor of Marshall’s Cove Marine Paint on Bainbridge Island Washington. He also teaches at WoodenBoat School.

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Preparation is the key to any good paint or varnish job. Many boats come to my refinishing shop with a good-quality finish but with ragged edges that indicate a poor masking job. Some other boats I have seen still have leftover residue from masking tape. This makes the paint job look much worse than it really is. Here are some tips to make masking easier and give you a better-looking finish.

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Purchase and Storage

There are many types and brands of masking tape: green, blue, gray, silver, fine-detailing, long-mask, easy-release, masking paper, and the old standard natural-color masking tape. There are general-purpose tapes and specialized tapes; some are good, some not so good. To get the best results you’ll need the appropriate tape for the job at hand.

I primarily use 3M products, not because they are better, but because they are widely available and the company offers such great variety. The tapes I use the most are the blue long-mask (No. 2090) and the greenish plastic-like Fine Line tape (No. 218). Other favorites are the green and silver extended-use and easy-release tapes. I use these latter two only when working outdoors, in extreme conditions.

Gary Lowell

Store individual rolls in plastic bags. The tape’s edge does most of the work; bagging is the best way to ensure that the edges will stay clean between uses.

Despite its availability and low cost, I do not recommend the standard natural-colored masking tape for use with marine coatings. The adhesive is too strong to peel away easily, it may leave a residue, and I have found that it doesn’t leave a clean edge.

Proper storage is important and often overlooked. Remember, it is just the very outside edge of the tape that does the work. If the edges of the roll are exposed to dust and dirt, particles will stick to the adhesive, making it difficult to get that clean, sharp edge. If you set the roll down on a dusty surface, that roll becomes useless as a fine-detailing tape. Be careful when buying rolls of tape through mail-order companies, too. Individual rolls are often dropped into the shipping box with packing peanuts, covering the adhesive edges with dust and dirt particles. Although some rolls are individually shrink-wrapped, the plastic usually does not fully cover their sides, and it is perforated in places, leaving some areas exposed and vulnerable to damage. To avoid these problems, I buy all of my tape in bulk packages of nine rolls that come double-wrapped in plastic. Keep individual rolls in sealed plastic bags and take care to keep them clean while in use.

Gary Lowell

Once the tape is lying fair on the boat, burnish it with your thumb, noting how the tape changes color when it is pressed down.

Masking 101

The main reason we use masking tape is to get a crisp line between two different colors. Let’s say you want to mask off an area to paint a waterline stripe, as I recently did at my shop (see photos at left). It is important to make sure that your line is clean and fair.

Here, the topside varnish and bottom paint have already been applied, meeting at the scribed boottop lines. Before applying tape to the boat, unroll and fold over the first little bit of it to make a tab. This will help immensely when it’s time to remove it, especially if you have gloves on. There will be situations that require a tab-less piece of tape, but make tabs whenever possible. Begin at a corner of the stem or transom and roll out about an arm’s length of tape. Press the tape lightly against the hull as you work your way along it. It is better to use a few long lengths rather than several short pieces. Longer lengths better enable you to make fairer lines.

Gary Lowell

Left—For a tight radius, use a 1⁄4″ fine-detailing tape. This will wrap much more easily than a wider type. Right—Once the fine- detailing tape has defined the edge, use a wider tape to mask the brush-line area.

Once you have applied the tape lightly to one side, sight along its edge from bow to stern, then go to the other end of the boat and sight the opposite way. If it looks fair in both directions, press it down firmly. If not, lift an end and retape the unfair section. Then, press firmly to burnish the tape against the surface, making sure to get good contact throughout its length. You don’t need to press down on the whole width of the tape, just the edge that is doing the masking.

There are very few places on a boat where you’ll have a straight line. Most masking lines will be curved; some, very tightly. While paper tapes allow for slight curves, plastic tapes will bend much better. If you need to follow a tight curve, I suggest using a thin (1⁄4″ ) plastic fine-detailing tape or other conformable tape. Its narrow width will let you wrap it around the smallest of radii, such as a small cleat or other deck hardware. You may then add wider tape outside for more protection.

There will be situations where you’ll need to mask a wide area to protect surfaces from drips or over-spray. Taping paper or plastic sheeting over the area is the best method. However, don’t rely on a simple run of masking tape for both tasks. Use one run to get a nice, clean masked edge, and then tape the masking paper to that with another line of tape. The second line of tape does not have to be the expensive plastic type; it can be of the natural-colored, crepe-paper variety.

Post-Paint Procedures

Although many people think they must wait for their paint to dry before removing masking tape, this is not true in the vast majority of cases. In fact, most often, prompt removal of the tape is critical to success. After you apply paint or varnish, leave the tape on for only the few minutes it takes to clean your brushes. Keep your gloves on. Then remove the tape by grabbing the little folded tab and gently pulling it back beyond 90 degrees (see opening photo). I keep a putty knife handy to help grab those little pieces of tape that had to be applied without tabs. If the coating was properly applied, it should not run when the tape is removed. If it does, you have applied your paint too thickly. If you leave the tape on too long the adhesive may stick to the surface, leaving a mess; it may even pull off the paint.

Gary Lowell

Use a putty knife to remove small pieces of tape. The job will go much more easily and be neater than if you attempt this using your fingertips.

Sometimes you may find little “flags” of paint that have leaked under the tape. This means that there was a small length of tape that was not pressed down securely. It usually happens at tape joints, another reason to use as few pieces of tape as possible. Now is the time to get rid of these flags, before the paint dries. Fold a paper towel over the end of a putty knife or flat-blade screwdriver. Dip it in solvent, and then use the tool like a pencil eraser to carefully “erase” the paint flags.

Gary Lowell

Wrapped in a paper towel and dipped in solvent, the corner of a putty knife becomes an effective eraser of paint “flags.”

Masking tape is not just for paint. Use it any place you need a clean edge for a coating or want to protect an edge while sanding. If you have to add some caulk around a fitting or along a seam, don’t just squirt it all over the place. Take a few minutes to mask along the seam’s edges, apply the caulk, level it with your finger or a putty knife, and then remove the tape. You’ll have a nice, clean line that looks like it is supposed to be there rather than looking like a quick and messy fix.

Gary Lowell

Masking tape is not just for paint; here it’s used to mask a messy deck-caulking job. Notice the tab at the end of each piece of tape. Make tape tabs wherever possible for easier removal, especially while wearing gloves.

Remember to use the proper tape for the job, keep your tape clean, and, in most cases, remove it as soon as you’re done with your application. Follow these simple steps, and you’ll find masking to be a helpful process rather than a difficult task.

Exceptions to the Rule: When to Leave Tape in Place

As mentioned, in the majority of cases you should pull off the tape early. There are exceptions, though, such as when using epoxy or when there is a highly detailed masking job that requires several coats of paint. A good example follows as I describe a sign painter’s technique that I now apply to boat painting.

Gary Lowell

To prevent a contrasting color from bleeding under the tape, begin by applying a coat of the base color (in this case, white topsides paint), which acts as a sort of filler. Once the base- colored paint is dry, apply the topcoat as shown. Don’t wait longer than a day between applications. When the second coat has dried, carefully remove the tape.

This technique will produce a very crisp line on a smooth surface or a decent line on a rough surface. Let’s say we are painting a black covestripe on a white boat where there’s significant wood grain to contend with. The paint could seep under the tape through pores of the wood. Apply the fine-detailing tape as you normally would, making sure to press it firmly against the hull. Then before you paint the black line, apply a coat of white paint. This will fill in the tiny holes and seal the area between the tape and the wood. Leave the tape in place. When the white paint is dry, apply your topcoat of black. When you remove the tape, you’ll see that you have a razor-sharp line.

Gary Lowell, a Society of Accredited Marine Surveyors Surveyor Associate, owns Lowell Boats Inc. in Greensboro, North Carolina, and teaches Marine Painting and Varnishing at WoodenBoat School.

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A good finish depends on many factors, including the quality of the paint or varnish, the preparation of the surface, and the expertise of the painter. However, even with the best possible paint quality, preparation, and skill, success will be elusive without good lighting.

Light intensity alone is not enough. It’s the reflection of light from the surface that allows us to judge the quality of a coating: at the right angle of reflection we can gauge whether we have applied the paint too thick, too thin, or whether there are places missed altogether—so-called holidays. We can see the work better if we lower the angle of the light source relative to the surface.

My shop does not have the best lighting; one side of the boat gets far more light than the other. The lighting isn’t much better in the boathouse, where our 20′ sloop gets an annual paint upgrade. When varnishing round-sectioned spars in either of these spaces, it is particularly challenging to get enough light to reflect at a favorable angle.

Harry Bryan

Photo 1 — In the subdued natural lighting of a boathouse, the handheld LED lamp accentuates the difference between sanded surfaces and new finish, in this case varnish on the sheerstrake.

I think the natural light coming from a window gives a better reflection for painting than artificial lighting does. But of the artificial lights I’ve used, I have come to favor the LED type. LED lighting has an intensity of reflection that is lacking in incandescent or fluorescent technology, especially if the LED bulbs are of the “daylight” instead of “soft white” variety. It seemed worthwhile, therefore, to explore the possibility of making a lamp for painting that would use daylight LED technology. If this light were handheld, then it would be possible to position it easily so that the light would bounce off the surface at a favorable angle without having to contort my body to get that perfect low-angle reflection from a distant window.

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A single household LED bulb proved unsatisfactory, because the area of reflected light was too small to assure even paint coverage. Also, this type of bulb is designed to diffuse light in all directions and therefore doesn’t reflect as intensely as I had hoped. I then bought a battery-powered LED flashlight of the type that has a cluster of small bulbs; I found that they were concentrated to give a spot of light, which worked better than a single bulb but still didn’t cover enough area for my needs.

Harry Bryan

Photo 2 — Shining light at the correct angle and exactly where it is needed can help achieve an even coat of varnish or paint without holidays or sags.

Success has come with a shop-made lamp, shown in use in photo 1, that adapts LED strip lights intended to be mounted under kitchen cabinets so that they shine down on a countertop. The strips are 3/8″ wide, with an LED bulb every 11/4″. The strips can be cut to length and fastened to a surface with their peel-and-stick backing. Several strips can be wired together and then connected through an included 12-volt power supply that plugs into a 120-volt outlet.

I mounted the LED strips on a 3/8″-thick cedar board, to which I attached a handle and then a cowling made from a sanding belt ripped to a width of 21/2″ and tacked around the board’s perimeter. In use, I hold the lamp so that its light reflects off the surface being painted while the cowling prevents the lights from shining directly into my eyes.

This lamp has significantly improved my ability to turn out good paint and varnish work. I now have almost no holidays, and the few that do appear are easily found with a sweep of the light before the paint begins to set. Sags and “curtains” are also easy to catch and correct in time. The constantly adjustable angle of reflection required in finishing spars is far easier to achieve with this lamp, and poor ambient lighting is less of a problem, as shown in photo 2. I have even found the lamp useful outdoors on a sunny day, during which the intense backlighting while working on the shady side of the boat can impair vision.

Harry Bryan

Photo 3 — Attach the handle to the back of the lamp’s wooden back piece, making sure to leave room to mount the power supply, as shown, and also leaving room at the top edge for a 1/4″ hole for wiring. Vinyl electrical tape secures the cord to the handle and makes a comfortable grip.

To make the lamp, first cut out the back from a piece of cedar or other lightweight softwood, as shown in photo 3. The dimensions are 3/8″ thick, 5″ wide, and 8″ long. Round the corners to a radius of about 1/2″. The back can be coated with shellac or varnish if desired.

Make the handle 5/8″ thick, 11/2″ wide, and 7″ long, shaped below the back to fit the hand. Fasten the back to the handle with two No. 6 × 3/4″ screws. Also fasten the power supply above the handle on the back, as shown in photo 3.

The LED lighting strips are cut into five 8″ lengths, with the cuts made through the middle of the copper pads that show through the white strips every 4″. The positive and negative polarity of the strip is indicated in print adjacent to the copper pads on the strips themselves. Cut a notch at both ends of each strip, removing the negative (lower) half-pad at the right-hand end and the positive (upper) half-pad at the left, as visible in photo 4. Peel the backing from the adhesive strips and stick them to the back in five evenly spaced rows, as shown in the photo, leaving 3/8″ of wood above the top strip where a 1/4″ hole will be centered to lead the wires to the power supply. It is important to keep the writing on all strips right-side up, as the polarity of the top of each strip is positive while the bottom is negative.

Harry Bryan

Photo 4 (left) & 5 (right) — Left—Cut the LED strips into 8″ lengths, with the cut made through the middle of the copper pads, which are printed to show polarity. Then cut the lower (negative) pad away from the right-hand edge of each strip and the upper (positive) pad from the left end. Right—Solder a bare copper wire, shown at left, to the remaining pads at the left-hand end of each strip, which are labeled as negative. The black insulated wire soldered to its top end reeves through the hole at center and then connects to the negative pole of the power supply. Similarly, the bare copper wire at right should be soldered to the positive pad at the right-hand end of each strip and is, in turn soldered to the red insulated wire, which reeves through the hole and connects to the positive pole of the power supply.

Next, solder a piece of bare copper wire at each end of the LED strips, as shown in photo 5, connecting all the positive pads on the right side and all negative copper pads on the left. I used 14-gauge wire (1.84mm) taken from scrap left over from a household wiring project, although wire as small as 18-gauge (1.16mm) will carry the small current required.

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Solder insulated wires to the upper ends of the bare wires, as shown in photo 5, and lead them through the 1/4″ hole at the top center of the back. Cut these wires to length, strip their ends, and fasten them to the appropriate positive and negative terminals of the power supply on the back of the lamp.

The cowl, visible in photo 1, is made from a coarse-grit sanding belt 30″ long. A used one will work fine. The perimeter of the lamp’s back is 26″, so cut the belt to a length of 27″ to allow a 1″ overlap. Then cut the belt lengthwise to make it 21/2″ wide. Attach the belt grit-side out; otherwise, it will not bend around the corners of the back. Tack it to the back with 3/8″ or 1/2″ tacks, and use contact cement to bond the overlapping ends.

Materials

• LED lights and power supply. The strip lighting and 6-watt power supply used for the lamp shown in this article are made by Armacost Lighting, www.armacostlighting.com, and are available from Lee Valley Tools, www.leevalley.com, specify indoor natural white LED tape lights, with 30 LEDs per meter. The strips are sold by the foot; a 4′ piece is needed for this lamp.
• Sanding belt. The sanding belt for the cowl can be readily found at hardware stores, but a used one would work fine. (Another dark, dense, flexible material could be substituted.)
• Wire. The necessary lengths of bare and insulated electrical wire (16- or 18-gauge), are readily available at hardware stores. The red-and-black wire visible in the photos was left over from another project and came from an auto parts store.
• Wood. The back and handle can be made from cedar or any scrap wood that can be shaped to 5″ × 8″. A thickness of 3/8″ works well.

Trailing the power cord is a minor inconvenience that could be eliminated by using a rechargeable 12-volt battery pack, but only at the disadvantage of its cost and ungainly weight. Another small inconvenience is that holding the lamp prevents holding a paint container. For me, these problems are a small price to pay for achieving a consistently better finish on my boats.

Contributing WoodenBoat editor Harry Bryan lives and works off the grid in Letete, New Brunswick. For more information, visit www.harrybryan.com.

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In my years of teaching boatbuilding and repairing wooden boats, I’ve noticed many mistakes owners make in the upkeep of their boats—common practices, done with good intent, that can often do more harm than good. I’ve distilled these into a list of the ten most common ones I’ve observed. Being aware of these things should help to eliminate some frustration and expense. My list loosely follows the common order of seasonal work, from springtime commissioning to autumn haulout.

Sponsored by: Pettit Paint

1. Sanding and painting when the hull is dry

At some point, our boats spend time out of water. Whether hauling out for the winter, or for just a few weeks of maintenance, it is important to keep an eye on your hull’s moisture content. Is the paint cracking at the seams? Can you see through the seams? If so, it’s important to get some moisture into your boat so she will swell up before you paint, and even before you sand. Why do this before sanding? Because if the seams are open, dirt and sanding dust can work into them, and even good vacuuming doesn’t always clear them out. Painting then traps this debris in the seams. As the planks then swell after launching, their edges will encounter that accumulated crud. Chances are that a bit of stray sanding dust won’t hurt the seams after one year, but over a span of years its accumulation will restrict plank swelling and possibly cause leaks.

JAN ADKINS

Sanding and painting a dry hull invites dust and debris to accumulate in open seams, potentially restricting the ability of those seams to swell.

Before painting, a bit of “pre-swelling” by means of wet towels, a sprinkler, or some other method should close the seams. Resist the temptation to put more than a few inches of water in your bilge: boats are engineered to keep water out, and not to hold it in.

There’s another common malady caused by inadequate swelling, and I often end up repairing the resulting damage. Many boats have their planking screwed directly to the transom edges. When the transom’s thickness shrinks with drying, the plank ends can stand proud of the transom. It’s tempting to want to sand these projections off. But after several years of sanding plank ends flush with a dried-out transom face, critical planking material is eliminated, and splits develop at the fastening holes. Rot may soon follow. The well-intended sanding has eliminated the “relish”—the all-important material between the plank-end fastenings and the ends of the planks. Leave those projecting plank ends alone. After the transom swells back up, everything will align.

2. Additional caulking when the boat is dry

“I could see right through the seam, so I added some cotton!” That’s a common refrain I hear when a leaky boat comes into the shop. Caulking requires care. If you can see light through your seams, my first advice would be to wait. Even with a severely dried-out boat, you can’t assume it is going to be a leaker until it is back in the water and swelled tight.

KATE MCMILLAN/JAN ADKINS

Adding caulking to a boat when it’s dry can damage the seams. It’s best to swell the hull before determining that the caulking is inadequate.

There are many ways to get the moisture back into a dried-out hull, but if you are pressed for time and aren’t able to wet your boat before you launch, you can drive some really squishy stuff into the seams so that you can promptly get the boat back in the water. Slick Seam, a soft, waxy product made by Davis Industries, is the standard for this treatment. It is effective, but rather messy when it squeezes out. It also has a reputation for clogging sandpaper. For these reasons, it’s typically used below the waterline as a spot-treatment on problem seams.

Dried-out topsides that have been given a fresh treatment of seam compound will likely end up with a bunch of seams emphasized by proud beads of squeeze-out after a boat is launched the planks have swelled up. These beads might look bad, but their presence indicates a healthy boat because the seams have closed up naturally upon swelling. If you’re after a mirror-like paint job, you’ll have to scrape and sand that compound flush when the boat comes out of the water at the end of the season—and then maintain the hull’s moisture content so the seams don’t open again.

3. Overcaulking

This is an extension of the previous item. I have pulled enough caulking out of boats—layers and layers of strata, caulking on top of caulking—that I start to feel like a geologist. Before driving in new caulking, you must first take out the old stuff.

KATE MCMILLAN/JAN ADKINS

Overcaulking a hull can put undue pressure on the fastenings and frames.

If your boat is leaking, the caulking might be bad; it is, after all, a natural fiber, and it can rot. Reef out the old caulking (see sidebar below) and replace it; adding more on top of what’s there is only going to damage the seams.

Driving in excess caulking by means of a caulking iron essentially forces a wedge into your boat’s seams. It can increase the shear, or lateral load, on your plank fastenings as well as increase the width of the caulking seam. As the planks swell with moisture after the boat is relaunched, the pressure that builds up between the plank edges can actually put tension in the frames and tear them apart, like a rope snapping in two. The effect is especially bad with dense mahogany planking; cedar is more resilient and forgiving. Even if frames don’t break, you will likely have compressed the planks beyond their ability to return to their original widths because of a phenomenon called “compressive set”: if a swelling piece of wood is restricted to a specific dimension, it will never swell beyond that dimension in the future.

A Shop-made Reefing Hook

The tool of choice for cleaning out old seams is a reefing hook made from the tang of an old file or a flat-head screwdriver. Using a propane torch, heat the tang or the screwdriver tip to red-hot. Then, bend the handle (or tip) a little past 90 degrees and quench the hot metal in water. File the business end of the tool to the sectional shape of the seam. Judiciously placed in the seam and dragged along, such a tool is very effective at removing old cotton and compound. —Eds.

4. Wrong fastening type or size

Imagine this: You remove a piece of varnished wood every year for 20 years so its finish will remain perfect. The screw holes become fatigued. Or imagine a badly corroded screw holding a plank to a frame; its threads have weakened and lost their grip, and the wood surrounding the screw hole has deteriorated to the point that it will no longer hold a fastening of this size. In either case, the screws spin uselessly in their holes, and the most convenient remedy is to replace them with larger or longer ones. This tactic only works with proper preparation. If you simply jam a larger screw into an existing hole, the new screw will likely be too big for the original hole, and the countersink not deep or wide enough; the screw may also be too long. The result can be disastrous, with one or more pieces split. If you’re increasing the screw size, you must drill a proper pilot hole for the new screw, and this includes the pilot hole for the screw’s threaded portion, a clearance hole for the unthreaded shank, and a properly sized countersink for the screw head. If there is inadequate material for a larger fastening, it’s better to plug the old pilot hole with a whittled, epoxied-in plug and then redrill it for a screw matching the original one’s size.

KATE MCMILLAN/JAN ADKINS

Refastening with a larger screw, without redrilling the hole for the new screw size, can cause wood to split. A properly drilled screw hole includes these three elements: (1) a countersink, (2) a shank-clearance hole, and (3) a pilot hole.

5. Inadequate varnish

If you don’t have the time to prepare for and apply enough coats of varnish, you might think about another strategy. In my experience, a boat is not going to take the all-day, every-day abuse of the summer sun without a minimum of six coats—and afterwards at least one, but preferably two, maintenance coats per year. Anything less than that invites deterioration, which will require scraping back peeled or yellowing varnish to fresh wood and rebuilding the finish in that area. You might also end up sanding back graying wood to a fresh surface, and in the process lose some critical wood thickness. Varnish requires commitment.

KATE MCMILLAN

If time or money constraints preclude the proper maintenance of a bright finish, it’s better to use paint.

If your time and budget don’t allow you to maintain brightwork, consider paint or oil instead. Boiled linseed (see WB No. 254) is the oil of choice for most boat finishes; unlike raw linseed oil, it dries fast and forms a film. While oil is the easiest finish to apply, it does not give the same protection as a coat of paint, and it tends to blacken as it ages. It also is not as effective a moisture barrier as paint or varnish. However, when kept up, it makes a perfectly fine and time-proven finish, and it can keep rot at bay.

6. Inadequate preparation for paint

If you are going to paint, prepare your surfaces properly. Sand off all the gloss of the previous coat. For bare wood, rough up the surface adequately; too fine a sanding can burnish the wood, making it more challenging for paint to stick. Also, if you can, paint the whole piece. I often see thwarts with only their tops and edges painted, and the bottoms left bare. If moisture can get into one side easier than the other, it can ruin the finish and possibly warp the board. If at all possible, paint even what you aren’t going to see; it will make the wood more stable and protect against rot-causing moisture intrusion.

KATE MCMILLAN

Hasty preparation for painting can lead to trouble. All loose and flaking paint should be scraped away; surfaces should be sanded; and hidden areas, such as the undersides of thwarts, should be coated.

7. Inadequate pre-launch cleaning

Before you launch for the season, make sure your boat is clean. Get as much crud off as you can while the bilges are dry and you have access to a vacuum cleaner. Sanding dust accumulates everywhere. You likely gave the boat a good cleansing before painting, but that’s never good enough. Sanding dust finds homes in plank seams and at the junction of your keel and floor timbers; vacuum these areas using a crevice tool and a brush attachment. Water will pass more freely through limber holes if there’s not a lot of debris sloshing around in the bilge. A clean bilge will also help keep the pump from clogging.

KATE MCMILLAN/JAN ADKINS

Before launching, take advantage of water-free bilges by vacuuming them thoroughly. This will save wear on the bilge pump—and potential clogging—and it will allow water to flow freely through limber holes.

After the boat is launched, keep her clean. If I had my way, we would cruise barefoot and eat out of feedbags. There’d be no grit from shoe soles or bits of food to fall or get blown everywhere. But that shoeless vision isn’t always practical, so be vigilant with a broom and dustpan. And really watch out for stray potato chips: not only will they do an amazing job of plugging up your cockpit drains and scuppers, but the stains from the grease will have your decks advertising what you had for lunch.

8. Freshwater washdown

A clean boat is super important. When dirt accumulates in a crevice, it holds moisture, and the next thing you know you have rot. You need to wash that dirt off—but not with fresh water. A regular freshwater wash-down with a dock hose is fine for fiberglass boats, but not wooden ones. The fungus that causes wood rot requires warmth, wood, and water—fresh water, to be exact. Frequent fresh­water wash-downs, especially in concealed, poorly ventilated areas, can thus exacerbate rot.

JAN ADKINS

Regular freshwater wash-downs can promote rot in decks and top timbers. It’s best to sluice decks regularly with salt water, which helps to prevent rot.

Salt water is the answer. Old-timers sluiced their decks with salt water regularly, to keep planks swelled and rot at bay, and you should, too—especially after a rainfall. Salty water prevents rot fungus from growing and it also keeps deck planking nice and tight. Even your dinghy, if it’s traditionally planked, deserves a good dousing of salt water after you’ve bailed the rainwater out of it. Afterward, of course, bail out the salt water.

Having a squeegee or chamois to wipe standing water from seats and other horizontal surfaces prevents your own bottom from getting wet. It also prevents wear and tear from the salt left on that finish you worked so hard to apply.

In addition to salting, you might consider a canvas cockpit cover to prevent large amounts of rainwater from finding its way into the boat. A cover can virtually eliminate pumping on a boat that is otherwise tight. It also eliminates bird guano, which fouls finishes and bilge pumps. Just make sure the cover isn’t tacked down too snug; too tight a seal can restrict air movement and encourage mildew.

9. Improper support on the trailer

When the season is over and it’s time to haul your boat, you must be sure it will be properly supported on the trailer; errors in this department can lead to major work.

First, make sure the weight of the boat is distributed evenly along the length of the keel. If your trailer has bunks or stands, think of them as kickstands only. They are there to prevent the boat from falling over, but they should not hold the entire weight of the boat. You should be able to loosen one whole side and careen the boat over. Rollers are generally bad for planked wooden hulls: they tend to point-load the hull, rather than distribute the weight evenly. If the centerline structure is not supported, bunks or stands can press themselves into the sides and bottom of the boat. Most hulls aren’t built for these pressures, and they will deflect in those areas. The hull was built to have uniform pressure all over, not in a few localized places.

The problems caused by improper trailer arrangements can be magnified when coupled with ratchet straps. These straps are convenient and easy, but also powerful enough to split a plank. Use them with caution. I prefer using rope and a trucker’s hitch; this provides adequate pressure for keeping the boat from moving during transit. With the weight centered on the trailer, and with the trailer winch holding your boat forward, your strap should be tightened only enough to keep the boat and trailer together, to prevent bumps in the road from doing any harm. If your boat has a drain plug and is stored outdoors on a trailer, pitch the hull so the plug is at the low point and any water will run out if your cover leaks.

KATE MCMILLAN/JAN ADKINS

Trailers equipped with rollers to support a boat’s bilges are fine for many fiber­glass boats, but can cause plank-damaging point-loading on wooden hulls.

KATE MCMILLAN

Carpeted wooden bunks provide support all along the length of the bilges, while regularly spaced blocking or rollers support most of the boat’s weight along the keel.

10. Improper storage

Before the boat is put away for the winter, it should be thoroughly hosed off with fresh water and all surfaces allowed to dry. Salt draws moisture which, due to decreased airflow and sunlight, invariably grows mildew during storage. Also, I have seen a fair bit of animal damage to wooden boats by porcupines and squirrels attracted to a salt lick. With this cleanup accomplished, keep in mind these four aspects of storage that promote a wooden boat’s good health: support, shelter, ventilation, and humidity. Ignoring any of these items can lead to damage.

KATE MCMILLAN

Proper on-land storage includes adequate support, shelter, ventilation, and humidity.

Support

As with trailering, a boat that’s improperly supported on land is likely to go out of shape. If it has long overhangs, gravity will attack those first. Jackstands, shores, or some other sort of prop underneath the bow and stern will minimize their tendency to droop. If weight is concentrated on the stands rather than along the keel, the hull is likely to deflect in those areas, damaging planking and frames. As with trailering, the first step to properly storing your boat is to concentrate its weight along the centerline, typically on blocking.

When a boat does start to go out of shape, its seams can open up. When they do, an unsuspecting owner might be tempted to drive caulking into those seams when light shines through them. Caulking helps a boat hold its shape, and so this added caulking only reinforces the damage caused by poor support.

Shelter

The goal of sheltering your boat is to keep rainwater out of the bilge and to keep it from drying out too much in the wind and sun. Rainwater will either promote rot or, if it freezes, will expand and damage the planking. Wind dries wood the same way it causes chapped lips. Sun drives moisture out of planking and hull timbers. A good shelter helps keep the boat swelled tight by maintaining adequate humidity.

Shelter options range from purpose-built boathouses to humble tarps; the choice depends upon the size of your boat, your environment, and your budget. A dirt-floored shed provides the best storage for the least annual effort, as it tends to naturally regulate ambient humidity. A canvas cover, however, drawn down over the topsides, also can do a fine job of protecting a boat: the fibers of such covers tend to swell during rain to shed water, and their shrinkage in dry times permits healthy ventilation. Shrink-wrap, often considered the bane of wooden boats, can actually be a good option, too, as long as it’s adequately ventilated and carefully blocked away from the hull to avoid sealing in moisture.

No matter what you build for shelter, or where you store your boat, the focus should be on keeping a balance of moisture both inside and outside of the hull. A dirt floor is a good place to start as it typically stays damp. If you have a wooden floor—or in the worst case, concrete, which draws moisture from the air—you may have to supply moisture at some point if you want to keep your boat from drying excessively.

Ventilation

Air must circulate around and within a stored boat. On the interior, it’s best to pull up a few floorboards, and to leave drawers and locker doors open in order to promote airflow. Having the hull sit in the dirt or wet grass will promote rot. So, in addition to providing support, keel blocking allows airflow. Use blocks, sawhorses, or whatever is appropriate to your situation to get the hull off the ground.

Humidity

A stored boat requires a balance of fresh air and consistent humidity. One strategy to ensure that the wood holds its moisture is to do some painting before the cold weather sets in. In New England, it is common to do all maintenance in the spring. But if the base coats on both the topsides and bottom are solid all winter, and the interior is humid but exchanging air every so often, a boat might just require only a spring touch-up instead of an extreme makeover each season.

Humidity can be maintained if necessary with plastic drapes tenting the boat from the toerails or waterline down to the floor, perhaps with humidistat-controlled humidifiers or even buckets of water placed strategically around the tented-off area beneath the boat.

Darin Carlucci teaches sailing, building, and restoration at The Carpenter’s Boat Shop in Pemaquid, Maine. He and his wife, Serafina, are raising two girls, and he is also busy building a house for his family.

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Many years ago, one of the big varnish manufacturers had a regular advertisement showing a cowering boat owner eyeing a brightwork project with a feigned expression of terror, and saying “Vvvvvvvvarnish?” Such fear is a common sentiment among would-be and occasional varnishers, and for good reason: Varnish provides excellent protection while showing the beauty of the wood, but it takes a consistent commitment of time and skill each year to maintain it. And achieving a good bright (aka varnished) finish in the first place requires careful surface preparation and application.

There are myriad pitfalls that can compromise the job along the way, and a lack of maintenance during the season can ruin a fine job. Paint, frankly, is a better option for those who lack the time or inclination to maintain varnish. Indeed, vast expanses of paint (cabinsides, for example) accented by bright trim will look much better than poorly maintained varnish. Varnish, however, is not only rewarding aesthetically; because it’s transparent, it also can reveal potential areas of rot that show up early as dark, discolored spots before they become a serious problem.

Simon Adams

A block of foam insulation can be shaped to a contoured surface to create a custom sanding block.

Some great books and articles have been written on the topic of varnishing (see Further Reading at the end of this article). For those seeking a more succinct lesson than those tomes provide, all major varnish brands include on their labels a concise set of instructions. I’d wager that that’s where most of us take our initial varnishing advice. Yet, due to the space constraints of the can, these instructions are typically printed in a barely legible type size, and they leave some room for interpretation—especially for the first-time varnisher.

So, the goal of this article is to interpret the varnish can—to give a bit more depth to those instructions, without writing a book. A can might say to remove all dust. We’ll look at how we do that, and the other basics of varnishing, leaving aside tangential concepts such as two-pack systems, spray application, wood staining, and stripping of old finishes.

Sponsored by: West System

Preparing and Sealing Bare Wood

All labels will tell you the wood must be clean and dry before varnishing. But there are a few other considerations, too. Painters and varnishers have an old adage: “It’s 90 percent prep work.” Divots and unevenness in the surface will telegraph into the finish coat, so be sure to get your bare-wood surface as smooth and scratch-free as you’d like it to be when finished. If you can live with raised and uneven grain, then a thorough sanding is all it takes. But if you’d like a mirror-smooth finish, now is the time to begin working toward that.

Large, flat surfaces such as transoms and cabin­sides can be sanded with sticky-back sandpaper, which comes in a roll, mounted on a hard-rubber sanding block. Alternatively, the surface may be scraped smooth with a cabinet scraper—essentially, a small rectangle of thin tool steel with a uniform burr worked into its cutting edge; when drawn across the wood surface, the cabinet scraper raises the finest of shavings. Rounded and faceted surfaces may be hand-sanded without a backing block, but achieving consistent contact between the paper and the surface can be challenging in this scenario. A better approach is to create a custom backing block from blue foam insulation. To do this, cut off a block of foam of appropriate size, form a piece of 80-grit sandpaper over the surface to be sanded, with the grit side facing out, and rub the foam block back and forth over it until the shape is transferred to the foam. You now have a shaped block to which you can apply your paper. This works especially well on long, straight facets and rounds, such as handrails, railcaps, and half-round trim.

Simon Adams

Blisters in a varnished surface must be scraped away. The hard edges of the resulting craters must then be sanded flat before the crater is built up with new varnish. Use a backing block here; don’t create a divot by focusing your sanding efforts on the bare wood.

A quick survey of varnish labels reveals strong disagreement over what grit of sandpaper to use before the all-important first sealer coat is applied. One can I looked at specifies using 80-grit on bare wood, while another says 120. And still another recommends 180–320-grit paper. The theory of the coarser grits is that they’ll give the varnish more “tooth,” or mechanical adhesion. Lower-density woods will easily soak in the initial coat of varnish, so a finer grit is a good choice here; denser woods may require a coarser initial sanding, so extra care must be taken to sand with the grain to mask the scratches, because a fine finish requires no visible scratches in the bare wood. For most wood species, 180-grit is a good choice. The sealer coat (which we’ll cover shortly), if thinned properly, will penetrate the wood’s surface to give adequate mechanical adhesion.

Preparing Previously Varnished Surfaces

If your task is to apply a maintenance coat or two to an intact finish, rather than to varnish bare wood, then you must first clean the entire surface of grit and dirt, and then sand it with fine-grit paper; 220–320 grit is the right choice for this. But before you get started on that task, you should survey the surface for yellow blisters. These telltale marks show where the varnish has separated from the wood, and they must be carefully scraped away to bare wood before sanding can proceed. (If the surface is littered with these blisters, or if the majority of the finish is peeling, then you must strip the entire piece to bare wood—a process we won’t cover here.) A 1″ hook scraper, filed sharp, is the ideal tool for scraping away small blisters. It’ll dull quickly as you use it, so keep a file handy, and sharpen the scraper’s blade as soon as it can no longer remove fine ribbons of varnish—which will be fairly often if you’re scraping frequently. Don’t do this sharpening on deck; the fine steel dust will rust and make a mess.

If you’re scraping bare spots in a finish that’s been stained, then you have another challenge ahead: These bare spots must either be restained to match the surrounding finish, or you must live with the contrasting patches. Likewise, scraped patches in unstained mahogany are likely to contrast at first with the surrounding finish, though they’ll blend in as the finish ages. On the other hand, if you’re working on teak, you’ll find that scraped bare spots blend beautifully and immediately with the surrounding finish.

Scraped bare spots must have their edges “feathered”­—the hard transition from bare wood to varnish must be sloped by careful sanding. The goal here is to gradually thin the varnish around the edges of the crater, but to not remove wood. A sanding block is recommended, and careful use of a scraper can speed things up. With the scraping and sanding done, it’s time to apply a sealer coat to the bare spots—to “spot-prime” them—and then to apply three or more “build coats” to these spots (see application instructions, below).

Folding Sheet Sandpaper

For sanding long pieces of trim, handrails, spars, oars, and such, you’ll likely be using 9″ × 11″ sheets of paper. These should be folded and then cut into quarters. These quarters are then folded in thirds, as shown in the photograph, so that none of the grit surfaces touch. When one surface becomes clogged and no longer cuts, flip the paper over for a fresh surface. When that one is clogged, unfold and refold the paper to expose the final unused surface. This can also be done with half sheets—though for surfaces typically requiring pieces this large, you’ll likely want a sanding block.

Simon Adams

Sanding between coats creates dust; clean it up with this three step process: (1) vacuum, (2) wipe down with solvent, and (3) wipe with a clean tack cloth.

Sanding and Dust Removal

With scraping and spot-priming out of the way (if you had to do it at all), it’s time to sand the entire surface. This is a step that often befuddles the novice varnisher: The goal, after all, is to build up a thick coat of varnish on the wood. This must be accomplished by applying multiple coats, and you must sand between these coats, typically, to get the later coat to adhere to the earlier one. But in the process of doing this, you want to sand away as little of the previous coat as possible. A light touch and a fine grit are required for this task. If the finish is in great shape, then use 320. If it’s beat up or requires some leveling, then use 220.

There are two exceptions to this sanding-between-coats rule. The first is a technique called “hot-coating,” whereby a subsequent coat is applied to one that’s not yet fully cured, so the two actually melt together, chemically. If you’re new to varnishing, then I suggest you stick to the tried-and-true methods outlined here, and not be lulled by the promise of less sanding. The second exception involves wood coatings specifically formulated for no sanding between coats. They save the time of sanding. And they save material, as there’s no specter of sanding away the previous coat. Sanding between coats, however, has the incidental benefit of dulling the previous coat, giving a nice sharp contrast between varnished and unvarnished areas when you’re actually applying the stuff. Unless the light is just right, you can’t always see where you’ve been when you don’t sand between coats, and thus you risk “holidays” in your finish (see “Applying the Varnish,” below). The other drawback of not sanding between coats is that you lose the chance to eliminate the previous coat’s imperfections. Sags, dust, bugs, lint, unevenness, and other sins are repaired or eliminated with each successive sanding. My caveats notwithstanding, not sanding between coats is a significant time-saver, and once you’ve mastered the art of basic varnishing, it might prove worthwhile to look into these no-sanding-required formulations.

Simon Adams

Apply varnish by first brushing it on vertically, and then drawing it out horizontally with long, even strokes. Don’t overwork it in an attempt to make it mirror-smooth; trust that it will level out before it cures.

It seems antithetical to do all of that sanding, and then to be instructed to apply varnish only to a surface that’s clean and free of dust. But take heart: There’s an established protocol for removing dust from a surface. First, vacuum as much of it away as you can, using a clean brush attachment on your shop vacuum. If working outside, you can use compressed air to blow off the dust. Second, wipe down the surface with a rag that’s been dampened—not soaked—with paint thinner or some other solvent that won’t leave a residue. The rag itself should be clean and free of lint. The third and final step is to wipe the entire surface with a painter’s tack cloth.

Applying the Varnish

The man who taught me how to varnish had a rule regarding time of day: He’d never begin applying varnish outside after about 2 p.m. on a summer day. Why? Because humidity on uncured varnish will dull and cloud the finished product. I had this lesson driven home the hard way several years ago when, pressed by schedule to get a coat of varnish on my mast, I did the job after work, at 5 p.m. I knew better, but I guess I thought I was invincible. Within a few hours, the dew dropped on the partially dry varnish, and the next morning the finish on the “up” surface of the mast was cloudy, dull, and textured, while the down side was clear and shiny. Cool, dry weather—classic New England fall conditions—is best, as the varnish has a chance to level out before it cures. In fact, getting your varnish done in autumn is a great way to manage your varnish maintenance, as you’ll feel like a genius for having it out of the way come the press of spring and the promise of boating weather. One word of warning on this: The short, cool days of fall typically require an indoor workspace, because the dew dries late in the day and falls early in the evening.

The first coat on bare wood is the sealer, which should be thinned adequately enough to allow it to seep into the wood before it cures. When it dries, the sealer should all but disappear into the wood; there should be no ambition to achieve a heavy gloss finish at this stage. Thinning is typically specified as a percentage of the varnish in your pot, and the range specified by manufacturers varies depending upon the viscosity of the varnish. One brand of thick-bodied varnish calls for 50 percent thinning for sealing purposes; less viscous, more forgiving varnishes are generally thinned only 10 percent.

Don’t varnish straight out of the can. Instead, pour your varnish through a medium or fine paint strainer into a clean container. This filtering step is especially important if you’re using a previously opened can, because globs of cured varnish can inhabit the rim and find their way into your finish.

Once the sealer coat has dried, it’s time to scuff it with 220-grit paper—just enough to knock down any hardened fuzz on the surface, and to dull the shine, if there is any. With this done, wipe down the surface with thinner applied to a clean lint-free rag, follow with a tack cloth, and apply the next coat. Some manufacturers will recommend that this next coat be thinned by 25 percent, while others will counsel full-strength varnish at this stage. Again, your best bet is to follow the can’s instructions.

The ideal is to not thin your varnish at all for the subsequent buildup coats, but the reality is that your brush will drag after a while on hot days or on long jobs as the solvent in the varnish flashes off. A fraction of a capful of proprietary thinner should thus be added occasionally, to make the varnish flow properly.

Good brushing technique is a matter of experience and concentration. I have good days and bad days applying varnish, probably because I do it only a few times a year. Here are some of my common pitfalls, and how I’ve come to avoid them:

Sags—It’s incredibly disappointing to look back at a surface that was varnished only five minutes ago, and to see an unfixable sag propagating down it. Varnish, you see, has a short window during which it can be worked. Once it starts to set up—to skin over—further brushing will only make it worse. Let’s consider varnishing a sailboat’s cabinsides: I like to apply the varnish in adjacent vertical bands and, once the brush has been emptied of varnish, to brush these out horizontally. This technique “meters” the varnish consistently, and avoids great sags in the middle of the surface. The place I always get into trouble when doing my cabinsides is under the half-round trim that defines the top edge of the cabin. Varnish loads up under there, and no matter how carefully I inspect the area before moving on, it always seems to release a sag or two. To avoid this, I now mask the cabinsides and varnish the trim first, and then freehand the cabinsides once the trim cures. It takes a bit more time, and some tape, but the saved frustration is worth it. If you find a sag in a cured buildup coat, scrape it away carefully before sanding for the next coat.

Dust—This is a disappointing defect, too, though I must say that a small bit of dust in the varnish seems to disappear once the boat is in the water. Perhaps it’s that our focus shifts to other things once the season is underway, or we absorb the boat as a whole, rather than as a brightwork project. Anyhow, don’t despair if you get a bit of dust in your buildup coats. The time to really be attentive to this is when applying the top coat. Varnish on a still day, vacuum, wipe, and tack the surface carefully, even wet down the shed floor if your situation allows you to do so, and use a clean brush. If you still pick up some dust, remember: This is an ongoing process, year after year. There’ll be time for perfection next season.

Holidays—“Holiday,” as you likely know, is the painter’s affectionate term for places that didn’t receive finish, and should have. They are typically a mental concentration issue, though occasionally they may be the result of inadequate amount of varnish on the brush. Be aware of them. Avoid them. And know that you’ll get better at brushing the more you do it.

Brush marks—Brush marks are the result of one of two things: Either the varnish has been overworked to the point that it was curing while being brushed, or it was applied in short, choppy strokes that began in the “wet edge.” The wet edge is the “front,” if you will, of wet varnish that’s advancing along the unvarnished surface as you apply the finish. Always complete your brushstroke into this edge, rather than originating it there. And apply it in long strokes that unload the brush evenly. Short, choppy ones will pile up the varnish unevenly, possibly leading to sags. The idea is to spread a coat of uniform thickness, one that’s sufficiently thick to shine, but not so thick that it will sag. Whatever it takes to achieve this should be done: Speed of application, a good-sized badger-hair brush (1½″ or 2″), easily spread varnish (add retarder on warm days and accelerator on cold ones), and a “feel” for the process, all help.

People new to varnishing often balk at the idea of five to seven coats, thinking it an excessive amount. But that’s typically the minimum required to build up a good and durable varnish finish that will last all season—again, with sanding between each coat. You’ll know you’re sanding a fresh coat too soon if the varnish gums up your paper; you must wait to sand until the varnish doesn’t do this, but rather turns to fine dust. It takes one to two coats per year to then maintain a varnished finish in a temperate climate, and more in the tropics. A few months of neglect in hot summer sun will result in a dull finish, and a little more than that will often result in cracking in the surface, and eventual peeling.

Brushes: Bristle or Foam?

Badger-hair bristle brushes are the standard for serious varnishers. They are worth their cost, because they hold plenty of varnish and release it evenly and cleanly—that is, with minimal brush marks. With careful clean­ing and storage, they can be used year after year. Cleaning typically requires three rinses in clean thinner, with a twirl in a paintbrush spinner between each rinse. Then they can be soaked in kerosene or diesel and spun out before being wrapped in a clean rag and hung from a hook for the season; to use them again, soak them in thinner to wash off the kerosene, spin them out, and they’re ready to go. Never store them in a can of thinner, because remnant varnish solids will settle to the bottom of the can, contaminating the brush.

Foam brushes are disposed of after use. Their downsides are: (1) They don’t hold as much varnish as a bristle brush, so they must be dipped more often and thus long, even strokes can be a challenge; (2) they lose their stiffness after a period of time; (3) they don’t work well cutting into tight spots; and (4) they add to the solid-waste stream. Nos. 1, 2, and 3 are generally considered to be acceptable trade-offs for small jobs, or in situations where prompt brush cleaning is challenging or impossible. The solid-waste issue must be balanced against the chemical-waste issue of cleaning brushes with solvent. Neither one is zero-impact.

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