Chips, bubbles in gelcoat

Hardcore

Petty Officer 3rd Class
Joined
Dec 5, 2007
Messages
87
i need advice. i looked at a '76 wellcraft airslot and i was turned off because it has alot of blisters in the gel coat and in some spots 1/4" chips where it just flaked off. can it absorb water through this?

what causes this? the boat is in otherwise great condition and it is dirt cheap but i am concerned that due to the blisters and cracks that it may have absorbed water. i can easily repaint it but hull strength is most important. the boat had been moored at one point as well. thanks.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: Chips, bubbles in gelcoat

If the blisters are below the waterline, the absortion of water caused them, and they need to be fixed. There is lots of advice on how to fix, however, it is serious effort.
 

Yacht Dr.

Vice Admiral
Joined
Feb 26, 2005
Messages
5,581
Re: Chips, bubbles in gelcoat

There could be a few different reasons for what your describing..

Is this on the bottom ? .. at the waterline ? ..

Have some pics to show :) .

YD.
 

Capt'n Chris

Chief Petty Officer
Joined
May 21, 2009
Messages
461
Re: Chips, bubbles in gelcoat

Gel coat is not impervious to water. The blisters you see could be osmotic blistering. A few are simply the beginning stages of more to follow. Those should be repaired with efforts taken to avoid storing the boat in the water. Also, moisture, if any, can much more readily leech from inside your hull outward creating the same type of blisters. It is easy to find raw glass and voids which act as capillaries and channel water every where. If there is any moisture in your FRP behind the gel coat, it can also freeze compounding problems. We have also seen stringer systems broken loose inside hulls caused by frozen water.
 

redfury

Commander
Joined
Jul 16, 2006
Messages
2,655
Re: Chips, bubbles in gelcoat

I'm working out the blisters in my hull currently, you can see them on the last couple of pages in my restoration thread ( link below )
 

stubbsboogie

Chief Petty Officer
Joined
Aug 19, 2008
Messages
413
Re: Chips, bubbles in gelcoat

Sounds like it is osmotic blistering.Over time gelcoat can absorb water in between it and the glass. They are a nightmare to fix.

We had major blistering on our previous Glastron. It was our first boat and had been kept in the water for 7 or 8 years, which is what caused the blistering. I looked into fixing them and was told by my local boat DR. that I did not need to worry about them. That as long as it was not stored in the water it would be fine. Some may rupture and those need to be filled with marine tex. But ortherwise they are more cosmetic and not normally structural, they can be but not normally.

google hull blisters and you will get a ton of info.

btw that Glastron I was telling you about I sold to my inlaws and they use it everyweekend. That has been a couple of years ago now.:cool:
 

redfury

Commander
Joined
Jul 16, 2006
Messages
2,655
Re: Chips, bubbles in gelcoat

as long as they aren't much bigger than a dime at the biggest, I wouldn't worry about them too much unless you are more concerned with resale and cosmetics.

I'm tackling mine for cosmetic reasons. I knew they were there when I bought the boat and paused for a moment to consider whether I wanted to buy it or not. The answer should be obvious. :D
 

JBF 1962

Chief Petty Officer
Joined
Oct 29, 2010
Messages
533
Re: Chips, bubbles in gelcoat

I've got a few in a couple of spots, but they are really small, no where near the size of a dime, but they should probably be addressed before they grow...
 

6meter

Chief Petty Officer
Joined
May 15, 2010
Messages
525
Re: Chips, bubbles in gelcoat

Had a bunch on the bottom of my bought new boat after a couple of years. It sat in the water from May to Oct. I was told the cold water makes it worse. The boat is docked in my garage now and has no more blisters. When done using it, it comes out. Besides, the boat launch is 1/8 mile away.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: Chips, bubbles in gelcoat

Supposedly boat builders have addressed the blister issue and resoved it in the newer boats. Some use vinylester gelcoat, since it is more water resistent than poly gelcoat.

The answer for us older boat owners, or those unsure what kind of gelcoat we have is to use an epoxy barrior coat on the hull under the bottom paint.
 

JBF 1962

Chief Petty Officer
Joined
Oct 29, 2010
Messages
533
Re: Chips, bubbles in gelcoat

Is there a particular type of epoxy barrier coat to use, or should I just go to my local marine supply store and see what they have?
 
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