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 Post subject: Epoxy/Graphite toughness?
PostPosted: Mon Sep 12, 2011 12:55 am 
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Joined: Wed Mar 30, 2011 7:20 am
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Location: Adelaide, South Australia.
Just wondering how long lasting the epoxy/graphite coating often used will last. My understanding was that epoxy not varnished or painted deteriorates when exposed. Does the graphite minimise that?

And would it be tougher than a 2 pack polyurethane paint, (which is very tough)?

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Wed Sep 14, 2011 6:35 am 
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Joined: Tue Jan 05, 2010 8:56 pm
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Location: South Coast NSW Australia
I used a two part varnish (Hempels Diamond Finish Varnish) on my Okwata and found it incredibly tough. After about 12 months use though, I had scraped the hull a number of times and it was starting to look a little bit tatty. Those rotten oysters taste great but are a bugger on the bottom of the boat.

I then sanded the botttom of the hull back and coated it with the graphite mix. I have found the hull now to be much more slippery, sliding over weeds and logs etc. but I dont think it is anywhere near as tough. It seems to scratch much more easily and deeper now. After all, graphite is what is used for pencil lead and that is pretty soft. I guess the plus side is that it would be pretty easy to repair. Other people seem to swear by the toughness of graphite but I can only comment on my own experience. As for UV protection, it appears to be the general consensus that the graphite protects the epoxy from UV rays. I have only had graphite on my hull now for a few months so I cant form an opinion.

For my current build I am not going to bother with a graphite bottom. I know it is slipperier over weeds and stuff but I have found no measurable difference in the overall speed of the vessel and I personally dont think it looks as good.

These are my opinions but I am sure others will disagree. The choice is yours.

Cheers Roger

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Wed Sep 14, 2011 6:42 am 
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Joined: Fri Jun 18, 2004 8:14 pm
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Location: Greensboro, NC
I've found the graphite to be a little tougher than paint. It doesn't really do much going through the water but it does seem to allow the hull to glance off logs and rocks a bit better.

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Fri Sep 16, 2011 9:07 am 
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Joined: Wed Mar 30, 2011 7:20 am
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Location: Adelaide, South Australia.
What is the correct mix? Some say 10% by volume, some 20%. Or do you just add enough to make it black and still able to be applied smoothly?

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Fri Sep 16, 2011 1:04 pm 
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goanywhere wrote:
What is the correct mix? Some say 10% by volume, some 20%. Or do you just add enough to make it black and still able to be applied smoothly?


I get it to a pancake batter like thickness so I can still apply it with a paint roller. The thicker you can manage it, the more protection you will get.

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Fri Sep 16, 2011 5:19 pm 
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Location: Adelaide, South Australia.
Yes, that's what I thought. Thanks Matt. About how much will I need for my Sabalo?

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Fri Sep 16, 2011 5:36 pm 
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a pint should be more than enough.

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 Post subject: Re: Epoxy/Graphite toughness?
PostPosted: Fri Sep 16, 2011 5:37 pm 
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Location: Adelaide, South Australia.
Thanks Matt.

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