Best Filler for Repairing Screw Holes in Fiberglass

[David M]

A small screw hole is not a structural weakness, not really. Even if it were a structural weakness, stuffing fiberglass and resin in there will not bring back the long strands and subsequent strength that used to be there where the hole is now.

Get some epoxy filler, (I like Interlux Epoxy Filler), put it in the hole and fair it out. That's what the pros at the yards do.

[s/v Jedi]

Originally Posted by David M

A small screw hole is not a structural weakness, not really. Even if it were a structural weakness, stuffing fiberglass and resin in there will not bring back the long strands and subsequent strength that used to be there where the hole is now.

Get some epoxy filler, (I like Interlux Epoxy Filler), put it in the hole and fair it out. That's what the pros at the yards do.

No it isn't a structural weakness at all but it does gets to hold the screw again which is way beyond the design specs of fillers based on micro-balloons.

The ready-to-use fillers like the one you mention are often available in two versions: repair and fairing grades. You need the repair grade for this. It will be very similar (functionally the same) to the mix of micro-fiber and colloidal silica that I suggested. I would like to think that real profs mix their own thickened epoxy fillers using a base assortment of fillers, resin and hardener, instead of buying ready-to-use cans with wonder products.

I also know a 3M product but that is not epoxy based... it's vinylester : not as good in this case so be careful what you get... mix it yourself to be sure

ciao!
Nick.

[smithy]

Count another vote for Duraglass. For this problem, I'd drill out a clean hole, overfill the void with some overlap on both sides, then once cured sand it back to level, drill a new hole, and get on with it.

Another alternative, is to set the screws while the product is kicking over, so they "self tap" into place. Prevents cosmetic cleanup prior to installing screws, though - if you want it sanded and painted first, this won't work - but it's great for secure fixtures.