Blister repairs

[schilde]

The hull of my old Invader has quite a few small blisters. After reading all the stuff on osmosis in here and on http://www.yachtsurvey.com/ I am not too worried about the boat falling apart!

Most of the blisters are smaller than 20mm, mostly about 10mm so I am pretty sure they are just under the gelcoat, not in between layers. The thing is, I have scraped and burst several during antifoul removal (still ongoing!). What should I use to repair these minor cuts? Do I need to spend weeks drying out the hull (which is never going to happen)? Can I just repair with a blob of gelcoat? Do I need to use something stronger like 2-part epoxy (will it stick with some damp around?) or maybe should I use something like underwater repair which should set wet? I am a bit unhappy about adding extra chemicals to the chemistry that is going on already. The boat is about 25 yrs old and never had any blisters before, but moved from fresh water to salt about three years ago.

Many thanks for your tips or experience
Steve

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[oldsaltoz]

G'day Steve,

I have treated boats with what is often incorrectly called Osmosis. Have you had a sniff around a freshly opened blister? If it has a vinegar smell it will need to dry to fix in the long term. However, if not, I would be tempted to clean out the blistered area, give it a blast with a heat gun to drive any moisture off the surface and apply some closed cell micro balloons or 'Q' cells, mixed with fast set epoxy resin to the consistency of toothpaste. Sand off the next day and coat with 3 layers of the same fast set epoxy. a dab of compatible waterproof paint (2 coats at least) and antifoul.

Check it next time you antifoul and decide what if any further action may be needed.

I hope this helps

Avagoodweekend Old Salt Oz /forums/images/icons/cool.gif

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[Bergman]

1 Carefully gring out blister and taper the edges to allow proper fairing in.

2 Wash repeatedly in fresh water and allow to dry thoroughly. If using hairdry do not allow to get hot and leave for a period to dry further.

3 Line the hole with West System or similar epoxy and allow to set thoroughly

4 Fill hole with gel coat filler and when thoroughly hardened fair to smooth surface with wet & dry.

I think the secret is not to rush, particularly the drying bit.

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[schilde]

thanks Bergman and Oldsaltoz (nm)

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