I recently bought a 1989 Mohawk Blazer with a kevlar (+fiberglass?) layup. It has a few issues—I think all should be relatively straightforward fixes, but I’m totally new to composite boat repair. Kudos to all of the helpful posters on this forum—I’ve learned a TON from the generous advice you’ve offered (especially @pblanc & @bnystrom for being so dedicated and clear).
I’ve laid out three problems below, each with a proposed fix that I’ve gathered from reading as many posts as I could find on each issue. I’d be most grateful for anyone who can offer their expert feedback on my proposed fixes. I’m super excited to use this opportunity to learn boat repair.
The bottom of the hull is in good shape structurally—no spongey spots, deep gouges, or previous patches. Above the waterline, the hull construction is thinner. There are several groups of pinholes that run all the way through. All are very small, and I don’t notice any other structural differences from the freeboard with vs. without holes. I suspect that the canoe may have been stored on its side, allowing water to pool in these patches—that would explain both the degradation and why the pinholes are bunched together rather than appearing everywhere along the freeboard.
Proposed Fix: Epoxy thickened with colloidal silica or fiberglass fibers (following Patching Kevlar? - #2 by pblanc). Will this work for pinholes, and any advice on getting it to fill such small voids? Do I need to cover with a full fiberglass patch?
View of freeboard from inside (gunnels is up):
Same patch from outside, showing cracks in gel coat and some exposed fabric (gunnel is down):
Largest hole to be patched on the exterior (~1/4" diameter, no sign of composite cloth but not soft/spongey):
The exterior of the hull is chalky (=UV degraded gel coat, as I understand it) and has bright spots where lichen was growing. I’d like to prevent re-growth and dress up the appearance a bit. I don’t mind a bit of added weight to pull this off.
Proposed fix: Lightly sand the surface, clean, then apply a pre-colored gel coat. Fibreglast has some nice colored polyester gel coats and a styrene/paraffin wax additive for use outside of a mold. I think TotalBoat sells a similar pre-waxed gel coat that other posts have recommended, but only in white/neutral. I’m worried that trying to mix my own colorants will be hard to pull off in a consistent way in the short time before the resin starts to kick. I’d be grateful for advice on:
- applying gel coat over the thickened epoxy used to repair pinholes (any special prep for these spots?)
- feedback on Fibreglast colored gel coats or other vendor recommendations
- surface prep (what sandpaper grit? wet or dry sanding? good cleaning solvents?)
- the wax layer (leave it? remove it? replace/cover over with 303?)
The interior has some sort of sprayed-on fibers along the keel, but not along the freeboard. I suspect that a protective coating was then sprayed over these keel fibers and the freeboard kevlar/resin. The black dots are presumably to help the applicator see where they had already sprayed. I think the protective coating has worn off in places—the spray on fibers are starting to peel in one spot where they taper off along the freeboard, and there are places where I can just barely start to see fuzzing of the kevlar itself.
Proposed fix: Apply a thin coat of West System epoxy. I think this would hold everything down and seal it from water intrusion. My big questions are:
- Can anyone confirm that the spray fibers didn’t originally cover the freeboard on this boat? If they originally covered the full freeboard, I may need to do more to protect this area.
- How do you prepare such an unusual surface for epoxy? Sanding seems like a no-go, and how/what to clean it with seems tricky.