Gelcoat bubbles

Pun

Petty Officer 2nd Class
Joined
Jul 12, 2004
Messages
128
I've noticed that the bottom of my boat has some bubbles where the gelcoat seems to have delaminated from the hull. Pushing on them with my thumbnail wont crack the bubble or anything, but I wonder if I should be worried about it. Anyone have experience with this problem?
 

Terry H

Lieutenant Commander
Joined
Sep 25, 2001
Messages
1,862
Re: Gelcoat bubbles

You can fix it or not,depending on whether or not you put your boat in the water. Basically what has to be done is to grind away all the damage and repair as necessary. That could mean major repair having to do some repair from the bilge side, or mostly cosmetic and gelcoat repair. All depends as to what damage is found with the grinder. A picture would help, but once you start grinding the defect and damage away it's always possible that more delamination is present that cannot be seen. Chief ;)
 

rpgg

Cadet
Joined
May 27, 2005
Messages
7
Re: Gelcoat bubbles

I am looking at a used boat with a 1995 Johnson and another boat with a 1996 Evinrude. Can anyone tell me if this falls into the timeframe when these motors were having a lot of problems? Any history or recomendations?
 

tengals123

Master Chief Petty Officer
Joined
Jan 26, 2005
Messages
860
Re: Gelcoat bubbles

rpgg, don't post a irrelevent question into some-one elses post. I know ur a new member, but that's a no-no. Ask your question in the johnson outboarb section.<br /><br />BTW, I agree with the chief.<br /><br /> :) <br /><br />cheers
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: Gelcoat bubbles

Pun - how big are the bubbles, diameter ?? Do you intend to leave your boat in the water for longer periods of time or keep it on the trailer when not in use. Bubbles can be either gelcoat production failures or osmosis. The risk of leaving osmosis as it is, is far less than anyone though years ago. Try to puncture one of the bubbles with a sharp woodchiesel or someting. If there is a vinegar smelling liquid inside ( they can be dried out if boat has been sitting dry for some years ) then its osmosis. Repair the inspedted place when its dri with marinetex. No boat has ever taken in water due to osmosis yet, problem is mainly cosmetic, and they will grow then.
 

Pun

Petty Officer 2nd Class
Joined
Jul 12, 2004
Messages
128
Re: Gelcoat bubbles

there's lots of tiny bubbles about 1/8" in diameter. Only on the bottom of the boat. Nothing on the sides. This boat hasn't been in the water for 9 years, so I'm not gonna worry about it unless it starts flaking off. As I mentioned, I tried to break one. Pressed really hard with my thumbnail and it wouldnt pop. I believe this to be a cosmetic issue.
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: Gelcoat bubbles

From your description it sounds like osmosis, but after 9 years you will find it to be dry. If you sand and paint the area below waterline with 3-4 layers of epoxy primer ( international has one for this specific use ) it will never show up again. I tried that myselves and that was on a boat that only had been up for 4-5 years. What happens is the osmosis salts drags water in thru the porous gelcoat, and in winter it freezes and expands the bubbles.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Re: Gelcoat bubbles

You said the bubbles are about 1/8" in size, small blisters like that are normally in the gel coat, if they are larger it is normally deeper in the laminate. If they don't bother you don't fix them, if you can't sleep at night knowing that your hull has a cosmetic defect, then get out your wallet and be prepared to spend a lot of money.
 
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