I made two 9x5 keel fins from plywood. I don’t know what kind of wood. Scraps from my buddy’s cabinet shop. Nice looking. Should I seal them before I laminate? If so, what should I seal them with?
When we make keel fins we seal them using two methods. The standard way is to use laminating resin and 6oz cloth, one layer on each side. This sets you up for a good bead (about 1/8" but you decide) along the leading and trailing edges. At some point you may be able to lay up both sides at the same time to get a better, more symmetrical bead. Do this by mounting the fin to a working base the has a couple of sharp nails sticking up through it. The fin gets stuck onto the nails through its’ base edge (the part you don’t see). Lay up all your pre cut glass on a flat surface (with something like wax paper on it). The other way is to use milled fiber (like FCS glass powder additive) and mix this with laminating resin. Consistency is about that of a milk shake. With latex gloves, hand coat all sides of the fin and lean it up somewhere until it kicks. The second method depends upon someone who can glass fins on quite well as the bead must be built during this time. Be sure to seal all end grain regions as this is where you will get off-gassing when glassing the fins. UV resins have made life easier… Good Luck.