When it comes to contemporary wooden boat construction and repair, epoxy is essential. As versatile as good marine epoxies may be, no single formula is best suited for every job. We are big fans of Thixo Flex, a flexible variant of TotalBoat’s Thixo, a thickened epoxy.
Thixo Flex has several favorable attributes: it can be used on oily woods, dry, damp, or wet surfaces, and a wide array of materials including (according to the Total Boat website): “fiberglass, aluminum and other metals, glass and ceramics, and most plastics, including ABS, PVC, HDPE, LDPE, and polycarbonate.” It can be sanded, drilled, primed, painted, and is resistant to vibration and shock.
A flexible epoxy becomes especially useful when joining dissimilar materials. Dissimilar wood species, for example, will expand and contract at different rates when affected by moisture or temperature changes. An epoxy that cannot move with such variations may lead to failed bonds. Thixo Flex—fully cured—creates a bond very nearly as strong as regular Thixo while offering 15 percent more elongation.
We have used Thixo Flex with excellent results on almost all elements of boat construction and repair, from trunk bedding mahogany to oak, attaching teak knees to sapele plywood, fir frames to mahogany plywood, and solid mahogany rubrails to sapele plywood. It can also be used to make fillets and to wet-out epoxy-compatible fiberglass cloth or woven roving. It takes a little longer for the thickened epoxy to soak into the cloth, but it has better gap-filling qualities than does thin epoxy. At 72°F, Thixo Flex has a working time of 75 minutes, can be sanded in 7 to 10 hours, and is ready to take a strain in 24 hours.
Thixo Flex’s resin and hardener are contained in a single cartridge and dispensed simultaneously with a high-thrust caulk gun. The components are blended as they flow through a mixing tip, so there is no need to measure resin, hardener, and fillers. The tip of the cartridge can be cut to several diameters to allow for precise applications on small components to larger amounts in laminations that require a lot of epoxy in short order. The cartridge system does come at a higher price than an epoxy with resin, hardener, and filler in separate containers, but that cost is offset by being able to dispense only the required amount needed on each small project—there is no guessing on how much epoxy will be needed, and thus no wasted product. The amount of epoxy remaining in the mixing tip is usually significantly less than would be left over from conventional mixing and stirring in a cup. When we are done with a task, we store the cartridge with the old tip left in place; when we come to the next project, we simply replace the old tip with a new one. Thixo Flex has a shelf life of one to two years.
With its easy dispensing and ability to bond such a wide range of materials and to create lasting bonds between dissimilar materials, TotalBoat’s Thixo Flex now occupies a permanent space on the shelf of our little workshop.
Audrey, aka Skipper, and Kent mess about with their 15 boats in the Tidewater area of Virginia. Their adventures are logged at www.smallboatrestoration.blogspot.com
Is there a product that might be useful for boatbuilding, cruising, or shore-side camping that you’d like us to review? Please email your suggestions.