Epoxy has revolutionized home boat building. With it a builder can turn inexpensive materials into what is literally a one piece structure, without traditional boat building skills. Because epoxy is gap filling, you are assured of structural integrity with less than perfect joints. In fact an epoxy joint that has a quarter-inch gap is stronger than one that is extremely tight fitting. Beginners can now build a boat that is as strong as the designer intended without spending years developing a journeyman’s woodworking skills. It is in coating and protecting that epoxy really comes into its own. The main reason for buying a fiberglass boat is that it requires less maintenance than a wooden boat. With epoxy coating, an amateur can build a boat which is as maintenance-free as a production fiberglass boat while retaining the easy building and inherent strength of a wooden boat.
Of course this boat building revolution is not free. Using epoxy adds to the building cost. It will increase the building time and working it with can be messy. However, the extra time spent building with epoxy will be recouped quickly by your saving on annual boat maintenance and by maintaining value over time. For me the increased pride of ownership and decreased worry about environmental degradation of my creation is more than worth the small initial increase in cost and effort. Epoxy/plywood boat building has only been around about 20 years, and because most boats so built are still going strong, the ultimate life expectancy of epoxy/plywood boats is unknown.
The basic steps for using epoxy are:
1) Apply epoxy/fiberglass sheathing to the bottom, sides and decks
2) Apply three coats of epoxy to all interior surfaces
3) Fillet or round off all inside & outside corners
4) Epoxy glue the boat together.