Paint drying over epoxy (again)

[hoss]

I know this has been covered but here goes, I'm finishing up my Mollyhawk and I applied some Interlux (Silux) paint over the plywood which was coated in epoxy. When coating the boat I ran out of East System epoxy and used some System three which I had. It seems that the Interlux paint does not like the System 3 epoxy, in that it has dried everywhere exept where I have used the System 3. I know I should have prepped better and tested a small area before painting but (I didn't) How long should wait before removing the paint? (will it ever dry?) it has been 3 days and the paint is tacky but not really wet. Would a heat gun help to dry it? And what would be the best way to remove the paint.

[Elco's]

Read the label on the paint can. What does the manufacturer recommend to use as a thinner and to clean up painting equipment with? Use that product and rags to remove the uncure paint. Are you sure the system 3 epoxy was propperly cured before painting?
At times, solvents from one product will retard the curing of another product.

[Steve Miller]

Yep, been covered. Did you wash the hull before painting? Even better, did you wash the hull before sanding? Sanding alone will not get rid of the blush. It must be washed off. Warm water and a 3M scrubby pad is all it takes. You can see the scum in the bucket. Change the water often. Not much harder than washing the dinner dishes.

Sam Devlin talks about waiting a month to paint over epoxy. I have done it a matter of days on small work but for bigger stuff wait at least a week with no trouble normally after a few weeks. For painting I have used the Interlux Barrier Kote primer over epoxy. I have also used Zinser 123 Primer, water base, with good results so far on a test rudder. No drying issues over either primer.

The paint will probably cure. Can you get the boat out in the sun? I use System 3 and have had the worst drying issues with the West Marine house brand of paint. The Interlux Brightsides seems a bit better. Also Interlux Schooner varnish seems to lag in drying over fresh epoxy. This seems to be an issue with the type of alykd resins used in the paint.

I think there were some comments in the last series on this topic about overcoating the tacky paint. That seems to let it all go off and set better. Check the earlier posts.

Good luck.

[NormMessinger]

In my limited experience, washing the blush, if any, off System Three does not solve the problem with some paints not curing over it. Not all System Three's old fashioned epoxy hardeners cause blush, in any case.

In once case I had where the paint did not cure in a reasonable time the piece was small enough to get in the microwave. I got it pretty hot which the paint cured. Most recently, hardware store enamal which failed to cure on epoxy that was more than a year or three old did so when I let the stuff sit in the sun for a couple of days. Subsequent coats cured normally.

The trick of overcoating paint that had not full cured to get it to cure is a new trick to me. With my luck I'll probably have a chance to find out one of these days. It'd be worth a try.

[WindHawk]

Bet the wife loved THAT, Norm.

[NormMessinger]

Actually she tollerates quite a lot if that sort of stuff but you should have seen the reaction of her mother and aunt the time the visited and found a dead hummingbird laying on a paper towel in the refrigerator. Good thing they didn't come around when I was cooling down a rattlesnake so I could photograph it safely.

[Wild Wassa]

I had a snake wrangler visit earlier this year to attend to a problem. He told me about an elderly lady who he visited, who had a sight problem.

She had painted her shed green, but missed a bit on the side of the shed. When her sons came to visit, they asked her, "after doing such a good job why had she missed painting a strip on the side of her shed?" She said she hadn't. The snake wrangler told me that when he caught a large brown snake in her yard, the snake had green paint on it.

Warren.

[ 07-30-2004, 01:43 PM: Message edited by: Wild Wassa ]

[NormMessinger]

yi ya yi yi yi!

[Keith Wilson]

The paint may dry eventually (weeks) particularly if the weather's warm. I'd take off the paint, then lay on one more layer of epoxy, this time with a slight excess of resin. I'll bet you won't have the problem when you repaint.

The System 3 guys told me that the problem is usually a small amount of unreacted hadener, which interferes with the drying reaction of the paint. The epoxy mix is always a little off; just make sure it's off in the right direction. A little extra resin will react eventually by itself, they say.

[ 07-30-2004, 02:14 PM: Message edited by: Keith Wilson ]

[paul oman]

Interesting comments!

I've actually been able to apply exterior latex over just applied marine epoxy (i.e. wet on wet) without problem. Needs to be a good epoxy and a good latex. Great for spot repairs on a painted epoxy nonskid deck - where work time was limited to a few minute visit on the weekend - each step added a week or more to the tiny repair project.

paul oman
progressive epoxy polymers

[Keith Wilson]

:D :D Paul, I though I was the only one barbaric enough to apply latex paint over partially-cured epoxy. Works just fine, though, although it has to be at least to the sticky stage or you can't spread the paint. ;) AFAIK, what I said above about unreacted hardener applies only to standard oil-base enamels and varnishes; latexes don't seem to be affected at all, and I haven't ever tried fancy paint.