How To Apply A Graphite Epoxy Coating To Dacron
Geodesic Airolite Boats (http://www.gaboats.com)
Mixing Graphite flakes into epoxy makes an unusual tough coating. You can purchase some WEST SYSTEM® # 423 Graphite powder, sold where ever WEST is sold (6 Oz. container will treat enough epoxy to cover 450/500 sq. ft.) It is recommended to mix at a ratio of 10% by volume.
This is not a new idea and I can’t take credit for using it as a coating. Not to short change my creativity I did an experiment along similar lines about 40 years ago. I mixed some Graphite into epoxy and injected it with a grease gun into the warn out Kingpin joints on 1950 Plymouth. I was all set to invent this new idea when they stopped using kingpins in favor of ball joints. It passed inspection for another 2 years. So much for "Bearing Jazz" and the spoiled genius.
Henry Szostek has been doing it for a number of years on his rowing shells. He claimed that it increased his speed...fact is he has won a lot of races.
I recently received an Email from: Harold Wheeler, a disciple who has built a number of the GEODESICS, telling me that he did a job on the bottom of his Black Fly Pram. He beached on a bed of mussels at full speed and had no damage. The slick surface increased the speed by about 10%.
The concept got my interest and I applied some on a panel of Dacron covered plywood. The coating was the thinnest that I could apply (About 10 mills, about the same thickness as a post card) that had no holidays. It was troweled on and tipped off with a foam brush. I used the appearance of the wood showing through as a guide to the thickness...the wood should not show.
After it was well cured for a couple of days behind the wood stove I did some primitive testing. There was no way that a screw driver would dig into the surface, it just skidded and left marks that looked like a pencil scribble.
Treat mixing this as any nuisance dusty material with aspiration protection. You surely do not want to coat your lungs with this kind of stuff. I would suggest mixing about a half cup at a time using any low viscosity structural epoxy.
Now I have a kind of theory of what is going on here, after reading about Buckminster Fullerenes Bucky Balls and Nanotubes, the latest forms of carbon that have been discovered in carbon soot.
These items have unusual high mechanal properties in the makeup of their GEODESIC rod like frames. I would like to guess that some of these atom size particles are found in the Graphite flakes or at least have a relative connection that explains the toughness. Remember that Diamonds come from the same chemical family—Carbon.
The results of applying the stuff on the bottom of the EBENEZER were not outstanding. and some more testing is in order. I added graphite to a batch of the Superbond epoxy that goes with the kits. Well this material is quite thick and the Graphite only made it even thicker. I thought that a foam roller might apply a uniform coating...not so I ended up troweling it on with my favorite very flexible trowel. The results we horrible...something like a new hot top macadam highway.
Further investigating found that the best way to apply it is with a soft flexible squeegee used in rhe automotive trade for body work.
I'll say this much, the stuff is tough. It took a lot of hard work to file, scrape and sand to smooth down the lumps and bumps so that a thin epoxy Graphite top coat could be brushed on.
A layed on brush coat with the brush almost flat and dragged along worked fairly well. It should be applied thick enough that the substrate does not show through. Long sweeping strokes help eliminate the brush marks that occur.
I had a problem with this thick coat running down the slope af slanted surfaces. Some Cab O Sill should be added to the mix as required.
I did get a chance to trowel some of the thick material on a piece of the Dacron. as predicted it did not soak into thee weave of the cloth and resulted in good rip stop quality with a flexible tough coating.
would be worth trying on a boat bottom to the bare Dacron skin.
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