View Full Version : Epoxy over polyester
05-02-2009, 04:16 PM
Is it possible to put a coat of epoxy over the top of a layer of polyester.... The poly that is on the boat is in excellent condition and has not delaminated.
05-02-2009, 06:00 PM
Yes. Epoxy actually sticks better to cured polyester than more polyester will. Sand the old stuff first (80-100 grit) and make sure that there isn't contamination from wax, silicone polish, etc. on the old surface. Don't forget that the epoxy will still need a topcoat of paint or varnish to protect it from UV.
05-02-2009, 06:09 PM
I might add that I hope it's not new polyester or less than a couple of years old...might be a different story.
05-02-2009, 07:00 PM
Assuming that the polyester has been there long enough to harden properly and isn't still new, green, outgassing a lot of styrene fumes and still shrinking, there is no reson to suspect that the age of the polyester should present any problem.
Polyester gelcoat/180gm csm/peelplyed/620gms triaxial in epoxy/20mm duracore balsa/620gm triaxial in epoxy.
Hope it lasts.
05-03-2009, 06:11 PM
Do you want epoxy? Or do you really want paint? Modern two-part, high-end paint works better than gelcoat in my experience of you really want a durable, glossy, colorfast layer.
05-03-2009, 06:43 PM
Be sure to de-wax with the right solvent BEFORE sanding, not after.
05-03-2009, 07:06 PM
New polyester sticks to old polyester as well as polyester sticks to anything. Which isn't very well. Epoxy sticks to polyester just fine.
No manufacturer guarantees gelcoat. Any marine paint worth using guarantees five years.
Puka: your deck laminations seem a bit thin & if your balsa is end-grain blocks each & every block will print thru & you will have to sand & paint it anyway. Besides gelcoat is suicidely slippery when wet, even with a built-in "non-skid" stippled finish.
Ah well, too late now.
I will dress it up when required.
Thanks for the headsup tho'.
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