I'm working on hull of O'Day 19 that I bought last yr and immediately put in water. Just discovered these small bumps (< 1 cm in diameter) in several spots on hull. They sand off pretty easily but wondering what caused and how I repair. The very small cracks above the blisters weren't even visible at a glance until I saw attached photo. The bilge stayed remarkably dry and boat sailed well last yr. I first noticed bumps/blisters after washing with oxalic acid and thought they might have been caused by droplets of acid left on hull too long before rinsing ... but other reading since leads me to believe water could be permeating actual hull material. Would a good epoxy paint stop seepage if that is cause or do i need to grind out every blister and crack. Thanks for any suggestions.
Blisters on Hull
- Thread starter weh5748
- Start date
- Status
I believe the proper thing to do is to grind out every blister when you see them right when you pull the boat for the season. This allows the fluid inside to drain out. Then, let it dry completely, over a series of months (like, maybe at least 6, perhaps with heat lamps inside the hull to drive out water from the laminate and gel coat.) You can also wash down with acetone over the course of several weeks, as acetone can draw out moisture.
Once the hull is complete dried, filled, and faired, then you could epoxy barrier coat.
Do a bit of googling, there is plenty of info on osmotic blistering and repair on the interwebs. I am relating some of what I've read...
Brian
Once the hull is complete dried, filled, and faired, then you could epoxy barrier coat.
Do a bit of googling, there is plenty of info on osmotic blistering and repair on the interwebs. I am relating some of what I've read...
Brian
Thanks. I did check the web and was discouraged by scope of grinding out every blister, especially since I didn't discover them until a few days ago and the ice is out on Lake George. I understand this must be the right way, but looking for perhaps a one year solution and it did seem like if cause is leakage thru the hull exterior that perhaps a good waterproof/epoxy paint would at least halt the damage. Wondering if anyone has actually had experience dealing with these blisters ... lessons learned. Thank you for any thoughts.
You can't just paint over the blisters and expect them to go away or be fixed...
The whole hull grinding thing isn't that bad and can be done in a week or two if you have good weather...
http://forums.sbo.sailboatowners.com/showthread.php?t=140140&highlight=sanding+bottom
The whole hull grinding thing isn't that bad and can be done in a week or two if you have good weather...
http://forums.sbo.sailboatowners.com/showthread.php?t=140140&highlight=sanding+bottom
I agree an epoxy coat will not make the blister go away, but keeping it in perspective it is a 19 foot boat and these are cosmetic blisters. So if it were me I would just seal it up and go sailing. Like I said if he wants to do it right strip it down and do a full barrier coat, but that would likely cost more than the boat is worth.
I had some small blisters on my Catalina 22. I pulled it, let the blisters go down, and dry for a month. Put on 4 coats of Interlux Barrier coat (epoxy coat) and painted the bottom.
2 or maybe it has been 3 years later, I have not seen a blister swell up. My boat is a 1982.....just did not make sense to spend the coin on a boat I use once in a while and does not stay in the water when not in use.
I had a few on my O'Day 25 that I did grind down and repair.
2 or maybe it has been 3 years later, I have not seen a blister swell up. My boat is a 1982.....just did not make sense to spend the coin on a boat I use once in a while and does not stay in the water when not in use.
I had a few on my O'Day 25 that I did grind down and repair.
They are very small bumps and sand smooth easily. I tried pushing a couple in w/ my finger but they seem firm. I drilled a couple just thru the gelcoat and there was no apparent release or opening below. Seemed like solid material. I'm leaning towards sanding and painting as recommended above.
Wish I understood better how this happens. When I bought boat last spring it was on trailer and very dry and I didn't notice any bumps. I kept it in water all summer. Noticed no bumps/blisters when I pulled it out or when I cleaned hull. Then after being dry for 6 months it develops chicken pox. Is it freezing and expansion of trapped moisture or built up pressure from some other process?
Wish I understood better how this happens. When I bought boat last spring it was on trailer and very dry and I didn't notice any bumps. I kept it in water all summer. Noticed no bumps/blisters when I pulled it out or when I cleaned hull. Then after being dry for 6 months it develops chicken pox. Is it freezing and expansion of trapped moisture or built up pressure from some other process?
I had a wack of small bumps on my new boat. I spent 4+ hrs sanding it down! Then two Thick coats of Interlux Epoxi Barrier coat. I gave it a quick hand sand today to get the roller fuzz off before I finish coat it.
I plan 2 finish coats (topside paint) then 1 coat of anti-fowling. ( I can' get the color of anti-fowling I want. (Aquaguard Shark White) So I'm going to go with just one coat of blue and hope to source the other color in Ontario.) The US maker says I can get it here. But the distributors/sellers say I can't...?
Aquaguard is a latex product. It worked Great last year in my lake. So I want to use it again.
I plan 2 finish coats (topside paint) then 1 coat of anti-fowling. ( I can' get the color of anti-fowling I want. (Aquaguard Shark White) So I'm going to go with just one coat of blue and hope to source the other color in Ontario.) The US maker says I can get it here. But the distributors/sellers say I can't...?
Aquaguard is a latex product. It worked Great last year in my lake. So I want to use it again.
Attachments
- Status