How To Repair A Fiberglass Crack

Filling in the Gaps

There are many ways to repair cracks in fiberglass—which ane's the best?

Stress cracks, spider cracks, and hairline cracks in the decks of older boats are, of class, not rare. Sometimes, they're merely cosmetic, pregnant they don't penetrate the gelcoat. Sometimes, they go deeper and threaten an underlying laminate, which in many cases is cored. Because the latter scenario may evolve into a very expensive proposition (replacing coring materials in an existing deck is a messy, pricey task all-time left to the professionals at your thousand), information technology makes sense to address all suspicious-looking cracks on board your boat as before long as possible, especially in areas that feel a footling spongy (probably due to coring bug) when stepped on.

Earlier you lot begin, yet, a word of warning. There are numerous, inexpensive products on the market these days that purport to be easy fixes for hairline and other fractures in fiberglass laminates. I've personally tried two of the nigh popular of the lot—MagicEzy Hairline Fix and Captain Tolley's Creeping Fissure Cure—and, although certainly easy to utilize, neither 1 comes close to beingness a substitute for doing the chore the right mode, every bit follows:

Step 1 Effigy out what caused the cracks to begin with. Practise they emanate from a stanchion base that flexes? Do they spread out from a radius that vibrates or twists in a seaway? Practise they surround an expanse that feels simply a trivial spongy, as already noted? Think near it.

Step ii Then toughen the laminate that contains the crack or cracks by solidifying information technology, either by thickening with more fiberglass, replacing coring materials, or calculation structure. If you lot don't practice this, new cracks volition most likely appear, probably non too long afterwards you've but finished fixing the one-time ones.

Step three Now, in one case you've removed all hardware, toerails, and other paraphernalia that may clutter or interfere, break out a Dremel tool with a conical chip. Then follow each separate fissure with the Dremel as if yous were wielding a pencil. Employ the highest speed possible, since depression speeds may crusade the fleck to catch or swerve damagingly from your intended path. And let the Dremel practice the piece of work—several shallow passes will produce a cleaner, more accurate job than going for a unmarried, deep, forced march.

Stride 4 As soon every bit the crack has been channeled out, wipe it make clean with a solvent similar acetone and, using a plastic putty knife, flush-fill it with gelcoat matched to the color of the surrounding area (if the channel isn't as well deep); polyester filler (if the channel is of medium depth); or polyester resin and fiberglass strands (if the channel is very deep and wide). It's a good idea, by the way, to mix upward a couple of minor batches of gelcoat to help you estimate the color you lot demand. Also, epoxy tin can be used in place of polyester in some situations, although it tends to be much harder than poly and therefore more difficult to sand smoothen and finish. And don't forget to temporarily encompass all gelcoat repairs with plastic motion-picture show—gelcoat does not cure thoroughly when exposed to air.

Step 5 Finishing is the terminal aspect of a proper fix. When dealing with gelcoat, dry sanding followed by wet sanding, with ever more refined, smoother grades of newspaper (starting with 220-grit and working your way downwardly to super-fine 600-grit) is advisable, followed by a good wax or polish. When dealing with a polyester or epoxy repair, numerous cracks are usually involved, and you may exist looking at a paint job of some kind in the almost future.