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Re: S&G: graphite bottom finish *PIC*
By:Dan Caouette (CSFW)
Date: 2/8/2012, 9:26 am
In Response To: Re: S&G: graphite bottom finish (Bill Hamm)

: You'll need more than a single coat to get it black, most say it
: can be done with three. I used graphite and silica (lots more
: graphite than silica) on my test boat and for going on four
: years now I've tried to wear it off, as far as I'm concerned it
: can't be done.

: But mine is a dull black color, not shiny black.

Agree totally with Bill. You need about three coats. One will not do it. I lay them on starting with the fill coats.

A coating of just graphite and epoxy is about useless for abrasion resistance. You NEED to add the fumed silica (aerosil/cabosil) to get any toughness out of the mix. A mixture of about 10% graphite and 5% silica (by volume) works well and makes a very tough coating. You'll notice the increased toughness it when you try to sand it.

It is VERY hard to get a 100% smooth finish coat. I've had the best luck rolling and tipping it. It gets harder as it cures so I try to sand it smooth as soon as the epoxy is ready for power sanding. It makes a black mess without a vacuum attached to your sander. You can wetsand but it takes forever. The new consensus seems to be to wetsand it to 400 grit, with your final strokes going in the same direction of travel. My customers sometimes want the graphite a bit glossy so then I'll polish it. I'll powersand to 400, wetsand to about 1200, then polish with rubbing compound to a semi-gloss finish.

The picture below was taken during the construction of a hybrid Night Heron. The finish on the graphite is before sanding/polishing.

Messages In This Thread

S&G: graphite bottom finish
Randy Knauff -- 2/7/2012, 4:34 pm
Re: S&G: graphite bottom finish
John Abercrombie -- 2/7/2012, 4:56 pm
Re: S&G: graphite bottom finish
Andrew Sommer -- 2/7/2012, 9:38 pm
Re: S&G: graphite bottom finish
Bill Hamm -- 2/8/2012, 1:39 am
Re: S&G: graphite bottom finish *PIC*
Dan Caouette (CSFW) -- 2/8/2012, 9:26 am
Re: S&G: graphite bottom finish
Mike Bielski -- 2/8/2012, 11:49 am
Re: S&G: graphite bottom finish
Bill Hamm -- 2/8/2012, 3:23 pm
Re: S&G: graphite bottom finish
Mike Bielski -- 2/8/2012, 8:24 pm
Re: S&G: graphite bottom finish
Bill Hamm -- 2/9/2012, 2:31 am
Re: S&G: graphite bottom finish
Mike Bielski -- 2/9/2012, 8:09 am
Re: S&G: graphite bottom finish
Mike Savage -- 2/9/2012, 4:06 am
Thanks for the input
Randy Knauff -- 2/8/2012, 5:38 pm