"Popped" Blisters

[Tethys26]

The information on this board for blisters has been a huge help to me. I've done a good amount of reading, including Don Casey's book. My 1980 Gulfstar has a decent amount on her. She's been on the hard for about 9 months and I'm finally getting ready to have the yard do some repair. However, my plan was only for them to take care of the 15-20 large (2"-4" diameter) blisters:
A) to save a little money, because B) I plan to shave and epoxy a few years down the road and for now just want to enjoy her.
My question is this: Almost 50-60 of the smaller blisters have "popped" (or were popped by the yard...). Now that they've been pierced, do I have any other choice but to have those ground out too? Or, will the bottom paint seal those effectively enough to get me by for another 2 years? What are the implications of ignoring them and focusing on the bigger ones, if any? Thanks in advance for the help!
-Lloyd

[RichH]

Go immediately to http://yachtsurvey.com/blisters.htm and read the volumes of info on blisters. The above is probably the BEST website on the subject and its remediation. Especially read the section on how NOT to totally and irreversibly destroy a hull with DIY blister repair.

[I-33]

I second that! While some think David Pascoe (the surveyor of Yacht Survey.com) is an opinionated egotist, I think he is knowledgable and plain-spoken. To some, that may be abrasive, but I appreciate his honesty. He has years of experience and knowledge to back up what he says.

[Tethys26]

Thanks for the quick replies! I have read the site extensively and I agree it's a great resource. However, I wasn't able to find any distinction in dealing with blisters that are "sealed" and still contain water (which clearly can be left alone, if only to have them continue to slowly degrade), and those that which have been lanced, and allowed to drain. At that point there is a hole allowing direct access beneath the gelcoat. I fear the only response to those is to grind them out and fill them. Otherwise wouldn't the ***** or hole make water intrusion even more rapid?
-Lloyd

[sailingdog]

Tethys-

You should open up any "sealed" blisters, but be careful doing it, as the contents can be fairly caustic and under some pressure.

Then you have to grind out the blistered areas and let them dry and then patch and re-fair. Since you're generally doing the repairs with epoxy, not vinylester or polyester resin, it is usually a good deal more osmosis resistant, since epoxy is the most waterproof of the resins used in boats.

[Tethys26]

Thanks for the responses. I understand what the proper procedures for repair are. I also understand that sealed blisters (assuming they are small and not structural) can be left alone until I peel the gelcoat in a few years.

My question is what to do about those blisters that are "popped" and have weeped fluid out. Because they have popped, do I HAVE to do a full repair on them (even if they are small), or can I leave them alone, put on the anti-fouling, and address them later. Will the hull be severely damaged if I leave them alone?

Thanks!
-Lloyd

[k1vsk]

Bottom paint will not provide any measure of protection, consequently, you are leaving essentially open blisters for further deterioration to occur.
As a minimum, you need to grind back the openings and fair them with marine grade epoxy or other suitable filler. As you know for your research, without sufficient drying time and proper repair, the latent moisture will remain in the hull until a proper repair is done so you should expect the condition to worsen over time

[Tabris]

Tethys , Before you start to spen a lot of money on blister repair read the highly respected Jan DeGroot's Article on Blisters. You have to determine if your blisters are just in the gellcoat which is purely cosmetic or in the laminate which is structural and a serious problem . Almost all blisters are in the gellcoat , cosmetic and do not need expensive repair. The need to repair gellcoat blisters is a myth that keeps boatyards rolling in money.
The following is DeGroot'sarticle


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