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cruizerEd · 03-03-2017, 01:47 PM

I'm sure this has been covered but google and the form search hasn't yielded any results.

I have a fiber glass roof in good shape.

I have removed one of the mounting points for an old satellite antenna and that left three screw holes. It is in an awkward place and presents a tripping hazard.

After a through cleaning (paint thinner, alcohol, water) and removing all the crazed gel coat I have a conical shaped hole that is about 1/4 diameter going down to 1/8 for where 3 screws were.

The roof seems to be gel coat, fiber glass, ply wood, and very thin aluminum. The whole sheet can't be much over 1/4 inch thick.

I'm planning on filling these holes with marine epoxy thickened with fiber class powder. Any opinion on whether this is a good plan. I could always put some Sikaflex over the epoxy. But that seems unnecessarily messy. Same for putting down eternabond. Eternabond seems even more problematic if anything ever has to be mounted in that location in the future.

Any experience with using epoxy to make a nice clean flush repair?

I've attached some pictures of the same process but since these are under a vent mounted in butyl tape and sealed with Sikaflex I wasn't concerned about them. Those holes are very flush. That gelcoat damage was caused by a "top rated" tech who installed the vent in the first place. My intention is to make a similar repair but leave the holes exposed.

On a side note why would bother screwing into that thin laminate escapes me. The screws definitely had no bite. I can't see screws holding any where near as well as a good adhesive.

Thank you for considering my question.

BFlinn181 · 03-03-2017, 02:01 PM

Sounds like a good plan. Make sure it's thick enough not to drip through the hole. You can finish with a dab of a matching color to hide and protect the epoxy, not that it really needs it.

cruizerEd · 03-03-2017, 02:21 PM

Yes if this were real fiberglass I'd consider doing a gel coat repair but this is so thin that I think it is half gel coat. I would rather have the extra epoxy. Maybe I'll mound some gel coat over it.

Unplanned Tourist · 03-03-2017, 02:43 PM

A good dab of Dicor would do, but not as pretty.

johnhicks · 03-03-2017, 08:55 PM

Your epoxy plan is good. Otherwise a dab of 3M 5200 will do it.

gruelens · 03-03-2017, 10:52 PM

I removed the satellite dish from my coach resulting in some holes in the Bri-tek roof. I used Eternabond tape because I didn't want it to leak and I didn't want to touch it for a dozen years. The epoxy method would probably look better than the tape. I redid almost everything on my roof with Eternabond Tape 3 years ago and am pleased with the results.

YC1 · 03-04-2017, 04:15 AM

https://www.walmart.com/ip/Bondo-272...EpFRA240_QnRcg

There are lots of Bondo products with fiberglas in them already. Fill the hole and use a putty knife to scrape it level.

kerryvan · 03-04-2017, 04:22 AM

the best marine epoxy that I have found was marine tex, it was used on my motorcycle gas tank by prior owner, and when I went to rebuild the bike I had it sand blasted. The marine tex was holding and would not come off!!! the sand blast guy was afraid to push on in fear of putting holes in the gas tank. That stuff was fantastic, can even apply under water, and they advertise use for gas tank applications!!

Jake21 · 03-07-2017, 09:05 AM

We used marine tex when i was working on yachts. Man that stuff it good. Also, i have used jb weld with very good results on various repairs.

Off Road · 03-08-2017, 05:36 AM

Marine grade epoxy is good stuff, the only thing to be aware of, it tends to break down from uv exposure. You can mitigate this by covering it with gel coat or paint.

nothermark · 03-08-2017, 06:00 AM

Considering that you need to protect the final epoxy from UV I'd just start with sikaflex or eternabond. There is a good chance it will not seal at the joint between the two materials. It probably has polyester of vinylester resin and a heavy cloth as the layer. When fresh the resin molecules cross link into a very strong solid. When cured they are hard to really get to bond again because there is no cross linking so you are better off with a sealant designed to bond. If you want to persist in a good fill Bondo is polyester with glass chop. It will form a good fill but a poor seal. Paint will seal it.

BTW - thick, heavy, resin rich chopper gun type fiber glass is considered the cheap stuff. ;-)