painting over graphite epoxy

I have a stripper hull done with black tinted epoxy which I was planning on painting black, probably with Interlux Brightsides. But perhaps I might put a couple of fill coats with graphite epoxy and leave it at that depending on how it came out.

If I decided I didn't like the way the graphite looked, would there be any problem putting a couple of coats of primer and then Brightsides paint over the graphite epoxy? I guess sanding the graphite to prepare for primer might be a bit of a mess. Would there be any problem with adhesion?

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eric


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RE: painting over graphite epoxy

Eric,

I've never deliberately put any coating over graphite epoxy, but have accidently gotten some paint and varnish on it. I sanded off the paint, but left the varnish on.

Sanding the paint (S3 2-part linear polyurethane with cross-linker) was work after only a week of curing. It certainly didn't volunteer to come off.

The varnish (Interlux Schooner) stayed shiny for a few weeks and eventually I stopped noticing it. Not sure if it came off or just dulled to match the graphite.

So based on this highly informal tiny sample, I can say that paint and varnish can stick for at least the short term. They won't just immediately slough off. Beyond that, the deponent sayeth not.

Good luck,

Laszlo

 

RE: painting over graphite epoxy

   I've used graphite powder as a tinting agent between costs of epoxy, and in a final layer before paint, with no problem. It makes the epoxy easier to wetsand, although it is definitely messier. Give it normal prep, removing contaminants and sheen, and go for it.

RE: painting over graphite epoxy

Thanks for the notes.

One other question. The weave is mostly filled already. It was wetted out with clear MAS, then a couple fill coats with black dyed epoxy. Tho no finish sanding has been done yet, it is pretty smooth and fair already. I was thinking of graphite partly just for the ease of not having to paint the hull. But I probably should have thought about it earlier if that is what I really wanted to do. Any subsequent "fill" coats would be pretty thin now.

After finish sanding and fairing, would a few additional thin coats of graphite epoxy mix be enough to protect the hull from UV degradation?

How many coats? Any thoughts?

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eric

RE: painting over graphite epoxy

   Eric, my skerry has a graphite double layer cloth and epoxy bottom for landing thru the surf here in CA. It has taken all the abuse you can imagine and still looks great. I brought the graphite all the way up the first strake and when wet she looks like gloss black...if you look thru the photos I am there in front of the Surf-Nazis tower (they really only want lifeguards to have the fun of launching thru the surf in a dory!) So I sneak to less protected areas! Like others I had a dash of paint hit the graphite part and it took some elbow grease to remove...The graphite had been smooth sanded with fine steel wool so it wasn't just epoxy that the paint adhered to....hope this helps

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