Renn Tolman and others recommend you mix Graphite Powder with epoxy resin to make a kind of paint for bottom coating boats. It is said to aid abrasion resistance and to inhibit marine growth. The latter is in some dispute but there is no doubt about the abrasion resistance that this stuff creates (see article below).
Graphite Barrier for Bottom Protection
by Steve Fisher
My goal is to build a Wee Lassie stripper within the next year or so and to that end I have been repeatedly reading â featherweight Boatbuildingâ by Mac McCarthy. On page 43 he writes a paragraph on scratch resistance using a special powder. In fact that special powder additive is graphite powder so on my last order to Raka I added 16 ozs. of the stuff. Previously I had written about a semi whitewater trip I took on a local stream with my 5 panel Lâil Kate in the course of which I put some serious scratches in the bottom. I made the necessary repairs, including additional tape on the seams. It seems that almost every place I launch or land there are rocks and gravel so I continued to put deep scratches in the bottom, nothing really bad but they offended my esthetic sense.
When I got the powder I immediately had to give it a try. BTW if youâve ever handled toner you know what this stuff is like. First I taped off the area and then I gave it a rough sanding to improve adhesion. Mixed it per directions and proceeded to paint it on. Of course I used a chip brush and had to pull bristles all over the place. When varnishing a few hairs are no problem because of the light sanding prior to varnish but be more careful with this stuff. I had no idea how it would work but it sure looked very cool.
My first experience with the new bottom was a few days later at the Kingston Messabout and it seemed to work quite well. Since then I have paddled numerous times at my local rock pile and it works quite well for scratches. Doesnât do a great job of protecting the bow but as you can see from the photos the scratching does not seem to penetrate the epoxy barrier combo. The yellow tape is waterproof electricians tape which I think looks good and holds quite well in fact through a 2500 mile trip to Nova Scotia including a few mean storms.
1 pint resealable container, mix 10%-25% graphite to epoxy by volume. Use on last two coats - renew when needed.