How long should epoxy cure out, before painting?

A

Andrew Holley

Well-known member
On the last boat, I didn't wait too long, maybe a day or two after filling the weave of the cloth, sanded it and painted. Paint held pretty good.

But have alot more invested in this one, so I thought I better ask.
 
Seriously Lee, a couple weeks?? Dang, I think I only waited like 24hrs on my deck. The hull may have been longer. Do you think that could inhibit a good chemical bond?
 
Andrew,

You should probably call Larry at RAKA and ask him what his recommendation is. Personally I waited two weeks in the sun until the epoxy was good and hard so I could scuff the surface and paint. After only a day or so the epoxy could still be dented with a fingernail and would clog my sandpaper when I tried to scuff it. Of course it may all depend on which hardner you use and how fast it kicks over and how warm your garage is, etc.

Pete
 
It's a two part primer that gives "that last bit" of protection before paint. Ditzler(sp?) I think invented it and I think now that PPG is the one making it. Devlin recommends it highly and most of the guys on here used it...I didn't but wish I had.
 
I have had no problem with sanding and recoating and painting with 24 hour intervals with the right temp.. According to the West System technical manual, maximum cure strength is reached at 1 to 4 days with either the fast or slow hardener. It also states that epoxy shelf life with sealed containers should keep it usable for many years.

The WS technical manual also states that sanding between coats in needed for a good mechanical secondary bond. This probably because it develops a wax surface similarly to polyester resin. A minimum of two coats is needed for effective moisture protection, with up to six coats for around a 20 mil thickness. As for painting, it states to let the final coat cure overnight then wash and sand. It states that it is a good idea to begin coating within 24 hours of the final sanding.

.
 
Last edited:
Epoxy is in the process of curing long after it achieves it's initial hardness and is able to be sanded; supposedly taking a month or longer to achieve a final cure. The buzz is that during this period compounds that inhibit the binding of paint are generated. So, a couple of weeks at least on a big, expensive labor intensive project like yours. The longer the better.

Ed.
 
Andrew...I too like to wait several weeks but I'll be honest I've painted within a couple of days and had no issues. I have used Lou's FME and Parkers.

Brad
 
You must log in or register to reply here.
Back
Top