cracks in fiberglass

[michael_t45]

Hi all,was wondering if anybody has had this happen.When building tear I used 1/2 exterior ply,counter sunk all screws ect,then used 4 coats of epoxy fiberglass sanding smooth between each coat,then used automotive epoxy & surface primer and automotive urathane paint,when done there was not 1 flaw in paint job,now several months later I can see small cracks in the paint job following what looks to be the grain of the ply.and in some of the places the counter sunk screws are sorta showing up.Id like to know why it did this??????? Thanks

[planovet]

What kind of ply did you use? Did you cover the screw heads with an epoxy filler or something similar?

[satch]

Sounds like the ply is flexing. If so, not sure how to repair it, can try recoating, and fill the crack with more epoxy, but if it's still flexing, it may come back. Hope others with more experience will chime in for you.

[Esteban]

Michael, So sorry to read your epoxy over a plywood skin is cracking. Maybe, you could sand it down to the epoxy and add some more epoxy and fiberglass cloth for greater strength and protection from cracking plywood. Then paint it again for a nice look and UV light protection. Just an idea.

[michael_t45]

Maybe my plywood had a high moisture content from the getgo,then through summer it dried out some causing hairline cracks not sure,ya really cant see them unless your really close,so Ill just leave them for now unless it gets worse,then I mite cover it with aluminum & trim it out ,its just that I had a lot of money in the paint job & really liked the look of fiberglass, if I ever make another Id not want it to happen again. Thanks just trying to fig. where I messed up

[Esteban]

Michael, after looking at your album I see you put a lot of work and pride into your paint job. It's a Big Bummer (technical term) that it's cracking.

A local friend, Robert Spencer, had a similar cracking problem to yours with his teardrops painted plywood roof cracking. He sanded off all the paint and then rolled on several layers of epoxy over the plywood to fill the cracks. I helped him one day with the epoxying. He only used fiberglass tape at plywood joints. Later he again painted the teardrop. If I can get in touch with him he could share his experience and results.

Spencer is member here, using the member name robert spencer, though he rarely posts messages. I pm'd him thru T&TTT. If he doesn't respond sometime soon I can call him.