I’ve seen carbon mixed with epoxy and used on boat hulls and paddle tips. Where do you get it?
West System sells powered graphite.
So you may be able to get it in a marine store.
Also Pygmy sells it.
I use to be able to get it in cans at a good lumber yard or hardware store as they sell it for dry lubricant applications. I haven’t bought any for some time so can’t vouch if it is something you still could get locally.
Any place that sells laminating epoxy usually also sells powdered graphite.
My favorite is http://www.raka.com/. No fancy packaging to pay for, just graphite powder in a plastic bag. 8oz 5.75.
I used Raka’s graphite powder and silica microbeads among their other products to make custom skid plates for my Mohawk. The prices were great and the plates have exceeded my expectations in terms of strength and durability.
Are you sure you want a graphite bottom?
If you are looking for durability from hull dings and scratches, in the process of doing a boat build, you might want to research this more thoroughly in the builders’ forums. I was going to use graphite below the water line on a couple of boats I was building recently. However, I decided not to, as there were reports of builders not being too happy with their results. For one thing, there was not as much increased resistance from dings and scratches as people had hoped for; also, the graphite-epoxy mix resulted in a really slick finish that made off-water boat handling difficult (imagine putting the boat up onto your car)and that made black smudges on everything the hull came into contact with. After getting good advice on the forums, I elected not to go with the graphite. Good luck with whatever you decide.
I wonder about the “recipe” of those whose graphite bottoms rub off on their hands. My black bottom doesn’t do that. I use approx 30% graphite (by volume) and 5% fumed silica.
I don’t consider a graphite bottom to add strength or bump resistance, but it hides the scratches. Nothing as ugly as a scratched up varnish bottom. The graphite bottom is easy to touch up also. If I get a deep scratch (through to the glass underneath) I just mix up a small amount of black goo and squeegee it on.
Thanks for the formula, jjoven . . .
Maybe, after the hulls develop some wear and scratches, it would be a good idea to revisit the option of doing epoxy-graphite bottoms. I have seen posts where some have warned that a black bottom might make a large predator think you are a seal! Since we hope to take our boats traveling, this would be part of the consideration. I wonder how well red-pigmented epoxy below the water line would hide scratches?