thousands of bottom blisters

[Jmstee]

I started sanding about 24 hour after haul out and found thousands of tiny blisters that start to show as the paint wears thin. I ground a few out and they don't seem to go past the gelcoat. there is only a trace of moisture in them as well. How would you recommend repairing this. its an old boat and the budget is small. I want to prevent further damage as much as possible. Part of me thinks I should leave it be and let it dry for the winter then barrier coat and repaint in the spring. It just doesn't seem possible or wirth the time to grind each spot. Thoughts?

[rbk]

If it were mine I’d sand the whole thing down, let it dry for a bit, epoxy barrier coat, paint and go sailing.

[chowdan]

If budget is small, I'd probably leave it alone, especially if the boat value isnt much.

If you do leave it to dry out over winter, youd need to pop them and then barrier coat for it to actually dry out.

If it were my boat, I'd leave them be, barrier coat and paint right before splashing and just go have fun sailing.

Do note if you pop them, you'll likely need to do a few skim coats to fair the hull smooth before barrier coating

Originally Posted by Jmstee

I started sanding about 24 hour after haul out and found thousands of tiny blisters that start to show as the paint wears thin. I ground a few out and they don't seem to go past the gelcoat. there is only a trace of moisture in them as well. How would you recommend repairing this. its an old boat and the budget is small. I want to prevent further damage as much as possible. Part of me thinks I should leave it be and let it dry for the winter then barrier coat and repaint in the spring. It just doesn't seem possible or wirth the time to grind each spot. Thoughts?Attachment 202056

[Jim Cate]

If you do leave it to dry out over winter, youd need to pop them and then barrier coat for it to actually dry out.

The barrier coat will PREVENT the laminate from drying, I believe. Its whole point is being a barrier to water, and works in both directions.

Jim

[drewm3i]

Paint blisters most likely.

[Nicholson58]

This is precisely the mess we had. I hired a sand blast guy. This blew open thousands just as you see. I used a die grinder with carbide burr cutter to fair them all. I then filled and faired before 6 coats of Interprotect 2000E. This was good but tedious. Don’t mess around with tiny tools or DA sanders. I used a big right angle buffer fitted with an approximate 12 grit flexible diamond grit wheel. If I ever did this again I would rent a peeler and strip off the gel coat in a few hours. Check out my photos. PM me if you want a more in-depth description. We have had no reoccurrence of blisters.

[kenbo]

Originally Posted by Jim Cate

The barrier coat will PREVENT the laminate from drying, I believe. Its whole point is being a barrier to water, and works in both directions.

Jim

^^^^ This exactly.

[a64pilot]

Depending on the value of the boat, I’d do exactly as he suggests, let it dry over Winter, then barrier coat in the spring and paint and splash.
Although ideally have it soda blasted or similar now.
It’s just in the Gel coat, and Gel coat is porous.

[Jmstee]

Originally Posted by Jim Cate

The barrier coat will PREVENT the laminate from drying, I believe. Its whole point is being a barrier to water, and works in both directions.

Jim

I understand that but do you think that if it sits over winter it will dry enough that sealing after will be ok and prevent further osmosis?

[kenbo]

Originally Posted by Jmstee

I understand that but do you think that if it sits over winter it will dry enough that sealing after will be ok and prevent further osmosis?

Before you put the barrier coat on the hull rent or borrow a quality moisture meter.

[boatpoker]

Sand it now to open up the gelcoat blisters then let it sit all winter before applying a few coats of barrier.

Gelcoat blisters are a cosmetic issue and never hurt anybody. As you say, it's an older boat and not worth the effort to strip the gel and do all that epoxy fairing work.

A moisture meter is useless in this case but if you want one, the best one on the market is about $45. Learn a little about them before you use one. .....

Moisture Meter Mythology and Flir thermal imager

[AndyEss]

Originally Posted by boatpoker

Sand it now to open up the gelcoat blisters then let it sit all winter before applying a few coats of barrier.

Gelcoat blisters are a cosmetic issue and never hurt anybody. As you say, it's an older boat and not worth the effort to strip the gel and do all that epoxy fairing work.

A moisture meter is useless in this case but if you want one, the best one on the market is about $45. Learn a little about them before you use one. .....

Moisture Meter Mythology and Flir thermal imager

Good advice. Your are describing paint pockets, not fiberglass mat absorbtion blisters

[AndyEss]

Originally Posted by Jim Cate

The barrier coat will PREVENT the laminate from drying, I believe. Its whole point is being a barrier to water, and works in both directions.

Jim

If the OP used the aerodynamic properties of teak creatively, he could blow dry the blisters - and get his boat to be as fast as a hoovercraft.

[Nicholson58]

If the tiny blisters are only in the gel and not cracked open painting over mostly works. If the blisters are cracked the paint will have a difficult time sealing them. Here will be contaminants within the void of the blister. Most of ours were this way and I found telltale blue bottom paint inside most blisters as I opened them. I also found without exception that every one had at least one glass hair from the first layup of sprayed chopped glass the hair in the cracked cover of the blister. I feel this was the water wick that caused the problem. Click on my images below my avatar to follow the repair. It took about six weeks to open, fair, fill and fair the bottom. Six coats of Interprotect 2000E took two days.

[Cadence]

Originally Posted by Jmstee

I started sanding about 24 hour after haul out and found thousands of tiny blisters that start to show as the paint wears thin. I ground a few out and they don't seem to go past the gelcoat. there is only a trace of moisture in them as well. How would you recommend repairing this. its an old boat and the budget is small. I want to prevent further damage as much as possible. Part of me thinks I should leave it be and let it dry for the winter then barrier coat and repaint in the spring. It just doesn't seem possible or wirth the time to grind each spot. Thoughts?Attachment 202056

Barrier coat paint and forget it.