Small cracks and bubbling in fiberglass

[ostojo]

I just purchased an 84 Bigfoot. Overall the exterior is in decent shape. I think the worst spot is on the corner of this one window. There is a bit of bubbling and small cracks in the fiberglass. You can kinda see it in this picture:



Should I be worried? I'm going to re-seal and likely completely re-install all of the windows.

Any thoughts on what the best approach to address the fiberglass would be? Is it likely that I could sand it out and do a gel-coat repair?

Thanks!

[cpaharley2008]

remove windows and inspect for rotted wood underneath, if not, repair the fiberglass and then reinstall the window with butyl putty tape

[mary and bob]

Jon: looks like the same stove hood vent as is on our Uhaul that I see above your window. Ours is bent a little too, and a wind driven rain will leak in. I'm working on adapting a plastic hood to put over it to stop that problem. For window molding that you ask about in another thread, try perfectfit.com and see if they have anything.

[Francesca Knowles]

I'm having some trouble seeing the damage you're describing- but it sounds like "blistering", a relatively common problem in the fiberglass boatbuilding world. It also occurs to some degree in other fiberglass applications including of course, molded trailers! (Contrary to popular opinion, molded fiberglass is not exactly waterproof- moisture intrusion can/does happen.)

There's a pretty good explanaton of blistering diagnosis as well as some repair instructions at the following link: How to Repair Fiberglass Blisters

Good luck!

Francesca

[Ron in BC]

Hard to say exactly because I can't see the problem well enough to say for sure what the fix should be.

Osmotic blistering is usually the result of prolonged immersion is warm water so I wouldn't expect that is your situation, but never say never

There can be two other kinds of defects that look sort of like blisters. One is swelling caused by a caustic chemicals. Don't ever try to clean stubborn stains with something like oven-off The second is a hollow void with a thin layer of gelcoat over it that may or may not break and look like a popped blister.

I wouldn't be concerned about whatever the exact situation is. Either way it's not a big deal.

Since you're going to reseal the window anyway why not post a close up photo of the area when its cleaned and exposed so that we can give you more specific repair suggestions.

Ron

[Donna D.]

Originally Posted by Francesca Knowles

There's a pretty good explanaton of blistering diagnosis as well as some repair instructions at the following link: How to Repair Fiberglass Blisters

Excellent tutorial!

[Carol H]

Jon here is a pretty good explanation for Gelcoat Crazing/cracking and causes that may be of some help to you. As others have said the photo isnt really clear enough to give you a good guess as to what may or may not be happening.

Pulling the window out and resetting them really isn't hard - have done some myself. But as others have indicated use butyl putty tape to reset them and leave the silicone caulking gun in the tool box. ;-)

[Donna D.]

Originally Posted by Carol H

.... and leave the silicone caulking gun in the tool box. ;-)

In the neighbors toolbox, down the street or in the next county