GK's D15

[gk108]

There is a lot of 6 oz cloth on my hull. It's covered all the way to the sheer. About half is covered with 2 layers of it. The skeg is covered with 9 oz tape.
I decided to use graphite for two reasons. First for the abrasion resistance. Second because it was much more economical than painting.

My D15 Album

[jacquesmm]

Pressure bag molding with a balloon! Very clever and I like the way the egdes come out, nicely round.

[Newt]

I am considering graphite for the bottom. As I understand it, epoxy needs to be covered for UV protection. Does the graphite give any UV protection? What is your graphite to epoxy ratio?

Thanks

Newt

[tech_support]

I am considering graphite for the bottom. As I understand it, epoxy needs to be covered for UV protection. Does the graphite give any UV protection? What is your graphite to epoxy ratio?

Thanks

Newt

Graphite does not protect from UV. In fact you should not use graphite except for places where it will be out of the sun, but not because of the UV, but because of the heat.

A black surface will get too hot, and the epoxy will soften. If you boat is going to be stored upside down outside, you should put a tarp over it (assuming the bottom is black).

As for ration, I have used from 10% to 50% by volume with epoxy. At 50% it gets a little thick, I like 25%.

Joel

[Newt]

So, if graphite/epoxy is applied strictly to the bottom suface. And, the bottom stays down, it's OK?

[gk108]

Jacques-
Thanks. I tried to take a picture after fairing and a coat of graphite, but man that stuff is black!

Newt and Joel-
I used a 25% ratio. As it turns out a plastic cannister for 35mm film is almost exactly the displacement of the bateau epoxy pumps. So, two shots of resin, one of hardener and a cannister of graphite makes a 25% ratio. Even with just one coat, the bottom has a whole different feel to it. Nothing like gelcoat or paint or plain epoxy.
Even under a tarp, heat may be a factor depending on climate. I had to start bright and early in the morning to get the first coat on before the sun got up overhead good. There is enough IR coming through the tarp over my building area to warm the hull up good in the afternoon. My slow hardener was done within 3 hrs yesterday, which was good. I was tired of standing by with the vac to suck up the love bugs.

I want to stress the importance of sifting the graphite while mixing. I didn't do that for the first 6 oz of resin and had lumps. I sifted after that, but when I got to the bottom of the roller tray at the end the lumps were still there from the first batch. I'll have to lightly sand a few areas before the next coats.

For this boat, if I ever encounter direct exposure of the bottom to the sun, I'm afraid I'll have more pressing problems to deal with than softening epoxy.

[tech_support]

So, if graphite/epoxy is applied strictly to the bottom suface. And, the bottom stays down, it's OK?

Yes

[gk108]

It was another nice day so I put on the second coat of graphite.

One more to go.

[ks8]

Looks good!

I wonder how well it conducts electricity?

Anticipating scrapes and such? Let us know how well it holds up. Maybe some pictures after a s-s-s-c-c-r-r-a-a-a-p-p-p-e or two?

What will be the final color of the topsides?

Keep going! Beat me to the launch!

[dewers]

Looks kick ass, I guess I have to order some more stuff from the site