gelcoat over epoxy

[glassman]

in finishing my 66 formula jr, had plans to gelcoat bottom but the pros and cons of gel on epoxy??? will it hold up,dont want to paint trailering .the rest of boat will be shot in awlgrip

[yokebutt]

Use an epoxy primer/drysail bottom paint instead. The Interlux product with teflon will polish out to a high shine.

Yoke.

[glassman]

good but on and off the trailer ,looking for more of a hardcoat

[boatbuilder.org]

It is my understanding that it is not a good idea to put polyester over epoxy, I think there are adhesion issues. Epoxy over polyester is fine though. I have not played with polyester much so my comment is not from first hand experience.
---Joel---
www.boatbuilder.org
www.devlinboat.com

[Deering]

From the System Three (epoxy manufacturer) website:

Can I put polyester gelcoat over cured epoxy?
In general, polyester resins won't cure properly or bond well to epoxy resin products without a "tie-coat" barrier resin in between. System Three SB-112 resin system can be used as a tie coat in between epoxy laminating or coating resins, and polyester laminating or gelcoat resins. Using this resin allows you to gelcoat an epoxy-built or epoxy-repaired boat.

[JR-Shine]

Yes, we sell (and use) the S3 paints. You can use them over polyester (gelcoat) if you use their "tie-coat", but its not a good idea. If you have used epoxy on the bottom, then just prime/paint it with whatever paint system you choose (awlgrip or S3), there is no need to use gelcoat. In fact the bond will not be as strong if you use gelcoat.

Gelcoat is a necessary evil of building a boat in a mold

Joel (A different Joel than above )

Boatbuildercentral.com

[glassman]

thanks for the info looks like paint it is just have to watch when putting in and out of the water

[Grantman]

check this Pro-Set web page that has info about epoxy/poly, tie-coats, mechanical tie-coats, etc..
http://www.prosetepoxy.com/application.html

[makeitfly]

Originally Posted by glassman

thanks for the info looks like paint it is just have to watch when putting in and out of the water

There are some excilent urethane two part paints on the market and they are usully harder than Gel coat . Check with the manufacturer about the hardness qualities and thickness required , This can be for the proper cure of the product when it is applied