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laszlo,
Iread your message from quite a while back about using graphite, 30%, some cab-o-sil, as a base. Then 40% final coat. What would you do to the boat if it were already painted?
About how much graphite and epoxy would you estimate for a CLC17?
thanks RodneyC
7 replies:
RE: using graphite
Laszlo,
Thanks for the response. Another Question. Would paint stripper be an option to all the sanding? I f so what else would you do to make sure the stripper didn't affect the graphite epoxy step?
Thanks, Rod.
RE: using graphite
Don't know, never used it. But I imagine that as long as you end up with a bare epoxy surface with no contaminents you'd be fine. Maybe a stripper to do the heavy lifting and finsh off with light sanding?
Any of you painter types want to step in here?
Laszlo
RE: using graphite
Laszlo, do I understand you to say that you use equal parts graphite powder and mixed epoxy? I tested some West 423 graphite powder with some 105 (50/50 mix), mixed it, and then added 206 hardener for a total product volume of about 2 oz. The result had a consistency of heavy cream that kicked off in 15 minutes. I was using West measuring pumps and while I may have made a mistake I’ve mixed gallons if epoxy over the years and never seen anything like this. Back to my original question. Is the 50/50 mix what you use? Thanks SEEYA Jack
RE: using graphite
Just for what it is worth.
West Sytems recommends a 10% graphite mix (by volume).
Mike
RE: using graphite
Jack,
Yes, these days I use 50/50 - that's 1 oz by volume of mixed epoxy/hardener per 1 oz by volume of graphite powder. First I mix the epoxy & hardener in the correct ratio, then add in the graphite. It hardens at the normal rate.
So typically I mix up 1 ox of epoxy plus 1/2 oz of hardener. Once it's thoroughly mixed, I add 1.5 oz of graphite. Once that's throroughly mixed I roll it on and tip it off with a foam brush. This is with System 3.
For what it's worth, I am now seeing a difference in wear between the 1:1 g/e and the 1:2 g/e + cab-o-sil. The richer mixture seems to be handling rocks, oysters and concrete better, while the cab-o-sil mix is handling sand better.
Laszlo
RE: using graphite
Thanks Laszlo, I must have done something way wrong. I was using those measurements with 423. I'd think graphite powder is graphite power and that the System 3 epoxy and West should work fine together so I'll try again and see what happens. SEEYA Jack
RE: using graphite
» Submitted by Laszlo - Wed, 8/6/08 » 5:39 AM
Hi Rodney,
These days I've switched to a 1:1 (50%-50%) by volume graphite/epoxy mix, no cab-o-sil. The cab-o-sil made it harder to mix so I decided to try and see if I could do without. The new mix works pretty well and I haven't noticed any difference in wear yet.
Years back I bought 1 lb of graphite powder. So far I've done a 16LT, a Wood Duck 12 and a 14-ft pirogue (twice) with that amount. I still have enough left to do the sailing dinghy that I'm currently building. The 6-oz can from CLC should be enough for several CH17's (or 1 CH17 refinished a few times).
I would definitely sand the painted area right down to bare epoxy before applying the graphite/epoxy mix. 80 grit is OK (be careful at the seams) because the g/e mixture is very thick and filling. If you roll it on and tip it off with a foam brush you'll never see the sanding marks.
Have fun,
Laszlo