Hull Blisters Question

[humbled1]

My hull below the water line has a lot of what appears to be blisters about the size of the diameter on pencil eraser. Non are really protruding out or seem be growing. Non of then need to popped open. I was told just to let it go. But if I decide to do something about it I read where you can repaint it with barrier coat. What would I have to do to prep bottom? has anyone done this that could enlighten me on this proceedure?

 

[amanphoto]

Re: Hull Blisters Question

They could be osmotic blistering. Water has gotten behind the gel coat and is making it pop out.

 

[Capt'n Chris]

Re: Hull Blisters Question

Gel coat is permeable and will admit moisture. You will have to locate the problem, put a stop to it so it cannot happen again, dry the boat completely inside and out and make your cosmetic repairs before you think about attempting a barrier coat. Drying the boat can take a long time. That would be the final step and it's a difficult one and must be done correctly or it won't stick. Your osmotic blistering can come from the exterior or the interior...or both for that matter. If you have moisture in your hull, which can be relatively small amount of condensation or many gallons of water from leaks, you'll have to remove all of it it or your exterior repairs will be futile. The raw glass on the interior of your hull wicks water like a sponge and holds it in the raw glass. In freezing climates, the frozen water in the glass expands causing more damage and additional room for more water that you don't see. Preliminarily, check for moisture in the gel coat with a moisture meter, which will most likely indicate what you already believe. If you do all of this, it is no easy task and could be a mighty laborious and expensive one. When the problems that you describe surface, one has to decide if it is worth the repairs.

 

[ondarvr]

Re: Hull Blisters Question

What is the boat worth, size, does it stay in the water all the time?

The cost and hassle to do a blister repair that lasts may not be worth it depending on the answers to these questions.

It involves removing all of the blistered laminate, letting it dry, and then rebuilding the surface.

Most blisters don't become a structural problem, just unsightly.

 

[humbled1]

Re: Hull Blisters Question

I thought about having the boat soda blasted. I called one outfit and he recommended using glass blasting instead and letting it dry out. I would have to barrier coat it after that

 

[humbled1]

Re: Hull Blisters Question

What is the boat worth, size, does it stay in the water all the time?

The cost and hassle to do a blister repair that lasts may not be worth it depending on the answers to these questions.

It involves removing all of the blistered laminate, letting it dry, and then rebuilding the surface.

Most blisters don't become a structural problem, just unsightly.

Boat is worth about 20K, 26 1/2' in water April to November

 

[msd58]

Re: Hull Blisters Question

What is the boat worth, size, does it stay in the water all the time?

The cost and hassle to do a blister repair that lasts may not be worth it depending on the answers to these questions.

It involves removing all of the blistered laminate, letting it dry, and then rebuilding the surface.

Most blisters don't become a structural problem, just unsightly.

Does it matter what size of the blisters?

 

[gonefishie]

Re: Hull Blisters Question

Mine only blistered where the bunks are at and they're small, the size of sun burn blisters. Only the part where the glass contacts the carpeted bunks. I only noticed it when I replaced the bunks and was underneath the boat. Nothing to worry about right?

 

[ondarvr]

Re: Hull Blisters Question

Like I said, to fix it correctly the affected portion of the laminate needs to be removed, whether its sanded, blasted or peeled, after that you need to replace the laminate that was removed. This means more glass and resin, either epoxy or VE, then comes fairing, epoxy barrier, and finish coat. This runs many thousands for a boat this size by the time you're done.

Doing a quick and cheap job will do little to prevent future blisters and will still cost a great deal, so if you decide to fix it, do it right. The other option is to do nothing and let the fish be offended by the nasty look of the blisters.

 

[ondarvr]

Re: Hull Blisters Question

Does it matter what size of the blisters?

The smaller the blister, the closer it is to the surface. 1/8th inch blisters are normally in the gel coat, but this isn't that common, larger blisters are in the laminate (most common type).

 

[wizbang 13]

Re: Hull Blisters Question

Interesting that the blisters are only over the carpeted bunks. Like the carpet scoured the parafin right outta the gel coat.

 

[ondarvr]

Re: Hull Blisters Question

Interesting that the blisters are only over the carpeted bunks. Like the carpet scoured the parafin right outta the gel coat.

There is no paraffin in the gel coat, It blisters because the carpeted bunks stay wet for a long period of time after being immersed.