Gel Coat on Epoxy

[fullkeel2]

So i just finished the last of layup on my seahood (thanks to all who gave great feed back) now i need to finish it. I picked up a can of Finish Gel Coat from West Marine. I was hoping that tomorrow I can sand the seahood and apply the Gel Coat. I used epoxy resin with the fiberglass.

Does anyone sea a problem with applying gel coat to day old epoxy?

Thanks.

[sailvayu]

Yes you will have a problem. You cannot put polyester over epoxy, it will not stick well. Yes there are ways to do it but be simpler to just paint. And trying to finish gelcoat is a real project I think I would paint even using polyester.

Good luck

[fullkeel2]

great. thanks for the heads up.

what should i use? what would be the easiest solution?

[sailvayu]

Easiest would be an off the shelf enamel, best would be sprayed polyurethane like awlgrip. you can get pretty good results with the enamel just won't last as long but then it is a quarter of the cost

Good Luck

[sv_makai]

Though I have never used it, I have seen several places that sell an epoxy gel coat. Do an internet search on epoxy gel coat and read through the results. Some interesting information.

[Mike156]

I’m confused, which is my normal state.

Have you finished fairing the exterior of the sea hood? If so, are you now looking for a way to protect the laminate?

Paint is the best finish for protecting laminate.

If you are still fairing, epoxy mixed with a filler will work much better than gel-coat. Surface prep is the key.

Mike

[barnakiel]

My boat has / had gelco. It was epoxy gelco, not polyester.

But maybe polyurethane paint is easier than gelco?

Hoping. Have just finished my project this way.

b.

[emeraldsea]

Once your done fairing, 2 part epoxyprime is best (must be thinned with special thinner) then "perfection" 2 part epoxy paint. If using 1 part paint I would still use the epoxyprime.

You can epoxy over polyester resin, but you can't use polyester resin over epoxy.

[s/v Necessity]

I guess some would disagree with the conventional wisdom that you cannot gelcoat (use polyester resin) over epoxy. I don't know why you would want to use gelcoat instead of paint, but according to westsystem you can (with results as good as if you were applying gelcoat over polyester). That is if I understand them correctly.

WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Polyester over epoxy

[Northeaster]

Although it was a smaller project, when I built new cabintop winch bases, out of epoxy, i used regular gelcoat to "match" the old finish, and it has held up well for the last couple of years.

[clockwork orange]

Are you done with the fairing and are ready to prime ? if so i hope you removed the amine blush properly .prior to sanding and applying the filler.Assuming you did and are ready to finish use a 2 part epoxy primer followed by a 1 part polyurethane such as briteside or toplac or preferably a 2 part polyurethane,i personally prefer to use car paints rather than boat paints for several reasons which are as follows 1/ they are the same chemistry ie,awlcraft 2000 boat paint is an acrylic urethane as are many car paints 2/you have many,many,many more color options.3/you can walk in to an auto body supply store in any reasonable sized town in the world and give them a color code and they will mix your color while you wait and you can walk out with everything you need to get the job done.4/if you can take in a part such as a hatch even if it is gelc
oated they can use there color match computer to create a formula and then use that to mix your paint.note,if your sample is old and oxidized you will need to polish a small section.
Steve.

[Weyalan]

personally, I would sand the epoxy, then apply at least 2 coats of 2-part epoxy primer paint, followed by 2 coats of 2-part epoxy high-build primer, then a 2-part epoxy top coat... with a very light sand between each coat if necessary.... but I'm no expert

[clockwork orange]

Guys,ive seen several recomendations in this thread to use 2 part epoxy for a topcoat,could someone please tell us the brands of these paints as i am not familiar with them at all,we paint boats every year but always use polyester urethanes or acrylic urethanes such as awlcraft or the car paints but i cant think of any boatyards around here using epoxy topcoats.
Thanks,Steve.

[jk475886]

As you already know you cannot put a polyester gelcoat over epoxy laminate...we repair loads of ribs with an epoxy layup..HOWEVER, to get round this we apply a Vinyl-ester resin to the bare epoxy matt, let this go tacky and then gel ontop of that. Vinyl-ester is a hybrid between epoxy and polyester, taking properties from both. it looks and smells just like polyester plus you use the same catalyst with it as polyester..its really easy

[Geminidawn]

I'm with jk475886 on this. This is a system I use often and it dose work. I leave the epoxy laminate a good 7 days under work shop conditions to make sure all the ammonia has evaporated, give it a good wash with scotch brite, hot soapy water to get rid of the amine blush, once dry cut back well for a key, vinyl-ester for it's great adhesive properties and then Flo-coat (Gel-coat with 10% wax additive)for finishing. Take care how you apply Flo/Gel-Coat it is prone to lots of tiny air bubbles. Cut back and polish up to your hearts content!