Coach Roof Cracks in Gel-Coat

[John]

This post will apply to Hunters in the ‘87 to ‘88 vintage which have black vinyl on the side if the coach roof around the main salon ports. The vinyl on our boat was beginning to look pretty ratty with occasional nicks and damage caused by the pressure washer. It was decided to remove it and apply a permanent black coating vice the comparatively temporary vinyl. Removed the Beckson ports and bought new ones. The black area was masked off and the vinyl removed – came off very very easy (took about 10 minutes). Under the vinyl was bright shiny like new gel–coat (good) except it had some cracks in it (bad), something like alligator cracks, like what happens when a large area of clay-mud dries except the cracks were very small. I decided not to open up the cracks and put epoxy in them (lots more work) and instead opted to sand (prep) the surface and apply Interlux Brightside Primer #4279. The cracks disappeared with the first coat (lookin' good). A second coat was applied and the surface was ‘like new’, a very satisfying job. Hey, this is going to turn out great. Not to worry! Nothing on boats can be this easy.The finished sanded primer (220 grit) was wiped down with a rag dampened with Brushing Liquid #333 per directions. A coat of Brightside Polyurethane black paint was applied and after about 30 minutes some cracks started to appear. The cracks were not as pronounced as the original but nevertheless they were visible, and basically in the same location as I remembered them. My fear was water could get in the cracks and cause blistering but this was discounted as a problem by a Hunter rep. A local yard recommended the cracks be opened up (Dremel tool with sandpaper tip?) and filled with an epoxy compound, faired, and start over again with the Brightside primer. I contacted the local Interlux rep and he agreed with the Dremel option to open up the cracks and recommended VC Watertight to fair the surface (it's a smooth paste) followed by the two-part 404 primer as the #4279 should not be applied over an epoxy coating; followed by the Brightside paint. It was a mutual feeling that the rag lightly soaked with the #333 brushing Liquid may have aggravated the crack situation. The plan would be to use a rag that is only minimally dampened with #333 next time, one that is almost dry, to avert the previous performance.Has anyone else had cracks in their gel-coat? Any comments/suggestions?

 

[Bob McDowell]

Don't Panic !

I also had the cracking under the vinyl when I pulled it off. It is "crazing" in the gelcoat caused by the heat under the black vinyl and the passage of time. The way to fix this, as per the instructions of the best fiberglass repair company on the Chesapeake (Osprey Marine Composites) is to sand the gelcoat, use fairing compound of your choice, and then redo the gelcoat.Bob

 

[John]

Follow-up

Thanks for the response Bob; it confirms what others have told me including the fix. Because vacation is close at hand I've decided to just apply a few more coats of the Interlux Brightside and basically cover the cracks as best I can. After two coats the crack coverage has been pretty good and today I'll put on coat #3. The first two coats were too thin, applied with a foam brush and thinned 5%, it dried too fast leaving some brush streaks. This next coat will be thicker, applied with a 3" wide roller and brushed after. Today is cooler so the dry time will be longer which will help. If the finished project doesn't come up to minimum standards it will be re-visited next year with a two-part finish. The 'expert' I talked to yesterday didn't think much of applying two-part finishes (Sterling, etc.) with a brush and said the glass jar "Preval" sprayer that auto body shops use doesn't have enough pressure and the tips don't put out as good of a spray pattern. In case anybody else is interested (and even if you aren't) the 'support' from Hunter was essentially zero - i.e., "Given the age of the vessel and that gelcoat was excluded from the original warranty any repairs would be atyour expense" - end of discussion. Never mind they decided to use black vinyl on a white gel-coat, the decision of which essentially caused this problem. Additionally, they have experts in fiberglass and have materials suppliers as a resource to help solve problems. I never asked them to fix it, although it could be considered a "latent defect" as the cracks were covered by the vinyl. all I wanted was some advice. Oh well, what did I expect? Probably a little bit more than what I got.Thanks again for the response.

 

[Tim gabrielse]

Black Plexiglass

On the 1987 Hunter Legend that I recently bought, instead of black vinyl on the finished gel coat, there is black plexiglass covering the same area that the black vinyl is covering on a later 1987 Hunter 37 next to mine boat.Did Hunter put this on and discontinue it on later models, Or did the previous owner have the same problems yoy had and tried a different solution. By the way, The black plexi-glass looks a lot better than the black "decal" my neighbor has.

 

[John]

Paint Results

The paint results with Interlux Brightsides is not very good, in my opinion, but adequate in my wifes opinion (the admiral). She said we've been working on this for weeks now and summer will be over soon and if we want to sail this year I'd better quit working on it and put it back together and I have a whole year to come up with a fixit. After some thought I had to agree - gota get some sailing in this year. Four coats and the stuff either ran or dried with brush streaks. I installed the new ports and we took off to the Port Townsend WA Hunter rendezvous. From, say, 10 feet it looks okay and from the inside the new ports look great, and no leaks yet (fingers crossed).Can't answer Tims question about plexiglass vice vinyl. I think I've seen some boats that had smoke plexiglass windows/fixed ports? with Beckson ports installed in them but I don't remember the model or year of the boat(s).Our old plastic ports were really crazed (the smoke plexiglass part)so we're thinking about comming up with a cover to keep the sun out and maybe the water also - will keep the gaskets and screens from turning green. If anybody has done this or has some ideas I would appreciate some input.