Gel Coat Blisters

[GreenLake]

About fairing and weight

Silvertip QuickFair from SystemThree ships at about 10lbs / gal. A gallon goes a long way; I don't think I've used that much yet.

Anyway, compare this to the weight of the hull at 500+ lbs.

If you add one gallon of fairing compound, you've changed the weight by < 2%.

Still worried? Then remember, you are spreading that weight over a considerable area near the warterline, you are not concentrating it at the tip of the centerboard or top of the mast.

Still worried? 10lbs/gal compares to 8.5 lbs / gallon for sea water. So you are adding something that's rather close to neutral buoyancy.

Still worried? Have a beer.

Oh wait, how much does a six pack weigh?

[K.C. Walker]

+1 for what GreenLake said.

If you want your boat to go faster, the benefits outweigh the negatives.

[seandwyer]

OK, OK, you've convinced me. I guess I thought a log more material was being added!

[talbot]

What about adding a sheet of glass in the depths of the bunk divots. My though is that it would both fill space and add resiliency.

Because the boat flexes there, I'm leery of just troweling resin to great depth.

What I don't know is whether you can bond glass well to the outside surface of gel-coat. I don't want to remove the gel coat from a negative area that needs to be built up.

[GreenLake]

Glass adds more weight.

You can experiment with the filler; one thing you could do is place different thicknesses on a batten and flex (after curing)

How deep are your divots? The makers usually give some maximum recommended depth for fillers. You could compare.

Epoxy bonds well to gel coat. Esp. if you rough sand it. What you may not want to do is use polyester resin because that does two things: it doesn't bond as well to cured gel-coat (not as good a glue) and it shrinks while curing, which would add stress and may even exacerbate your hollow section.

[talbot]

This forum is dangerous.
OK, it's my fault. I let you guys talk me into fairing the boat. Here's what the hull looked like after another two weeks of work. Pretty, huh?

BlistersFilledFaired

FairedHullCropSm.jpg (35.36 KiB) Viewed 9975 times

You ask, "So is it fair?"
Fair? FAIR? No, it's not fair. Nothing about gel coat blisters is fair. It's unfair, sick & wrong, cruel & unusual.
All I can say is, at some point I looked around my garage, ankle deep in epoxy dust and scraps of clogged sandpaper, pulled off my dust mask, and said, this has got to stop. And so I dragged the boat into the driveway, chemical-washed the hull, vacuumed the shop, and began painting. After four of five barrier coats, our boat "Blue Moon" has become the white whale:

HullBarrierCoat

whitewhalesm.jpg (27.4 KiB) Viewed 9975 times

Only eight more coats of various types to go. Sigh.

[Alan]

Just promise the boat you'll name it "Fair Maiden." It won't matter what the hull looks like.

What? Why yes, I do talk to my boat. You didn't say "white whale" out loud, did you? If so, I'd advise promising really good champagne for the christening.

[talbot]

The things I said to and about the boat while trying to fair the hull could not be written here.

[GreenLake]

Looks good. How do you get to 8 additional coats from here?

Oh, you are wet-sailing your boat, of course.

[K.C. Walker]

Yeah, kind of nitpicky work isn't it?! I restored a couple of cars in my younger days. Now that IS tedious nitpicky work.

It's looking really good! The fill spots look a lot more like the way the bottom of my boat looked. Sorry, didn't mean to egg you on.

[talbot]

Re: question about number of coatings: Here are the minimal coatings for interlux's "Interprotect" gel-coat repair procedure:
1: Clear seal of entire hull
(1.5--filling blisters and faring; not really a "coating")
(1.75--redo of clear seal because of new areas opened up by fairing.)
2-4: Barrier coat below waterline (including CB trunk interior).
5-6: Barrier coat entire hull (Including lower 6" of CB trunk)
7-10: Epoxy enamel below waterline (could be fewer, depending on bottom paint chosen).
11-12: Polyurethane enamel topsides.
12.5: Boot stripe enamel to protect epoxy from sun damage at waterline (optional, depending on bottom paint).

I finished coat #5 before this week's snow. It's too cold now to leave the basement open, and we can't stand the fumes from the hull epoxy. (Turns out epoxy paint is a different animal than epoxy resin. I suppose to enhance its brushing characteristics, the paint is loaded with volatile solvents that take hours to evaporate away.)

[talbot]

I'm sure you all have been wondering if my gel coat repair project would ever end. I certainly have.
It did, at the stroke of noon on Thursday. Here it is, at the moment I stepped away from it after 6 months.
Lots of insights, most of which I wish I had not acquired and which I hope no one has to know about, at least until after we've all gone sailing for a season.

DS 6546 Blue Moon after gel coat repair

FinishedBoatsm.jpg (69.37 KiB) Viewed 9869 times

[K.C. Walker]

Talbot, that looks great! How soon do you get to start sailing?

Winnipesaukee, my summer sailing venue, still has 16+ inches of ice. I think ice out is going to be a little late this year. The water temperature in Long Island Sound is still in the high 30s, so it's still going to be a while before I want to go out in that. Maybe it's time for a road trip south. The Midwinter's in Sarasota looked pretty nice!

[talbot]

We'll sail as soon as I can get the boat right side up and put back together. The county opens the marina Tuesday, but I would say Next weekend or the following. Best wishes for an early thaw back there.

[talbot]

Here's the full ventral view, which I hope to not see again for years.

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