Blisters in hull gel coat. How do I fix?

I have noticed a few blisters in my hull. Nothing major but I think I would like to repair them this winter. I've heard and seen marinas sanding the gel off the hull of bigger carvers and then spraying gel coat. Is this the right way?

Re: Blisters in hull gel coat. How do I fix?

You need to decide how much they bother you and how much money you plan to spend, it can be very expensive to do a good blister repair job. There is no such thing as a partial or spot blister repair, it's sort of an all or nothing type thing.

Post some pics if possible so we can see what type of blisters you are looking at.

Re: Blisters in hull gel coat. How do I fix?

Greg68S said:

I have noticed a few blisters in my hull. Nothing major but I think I would like to repair them this winter. I've heard and seen marinas sanding the gel off the hull of bigger carvers and then spraying gel coat. Is this the right way?

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I have never seen or heard of this process to remove blisters.. too labor intensive.

Got pics ?

YD.

Re: Blisters in hull gel coat. How do I fix?

I'll take some pictures and post them on Friday. So what is entailed in the process?

Re: Blisters in hull gel coat. How do I fix?

They really don't bother me. I just was not sure if it was a structural thing or not. My boat has never been bottom painted. Is bottom paint a good way to help protect it from further blistering?

Re: Blisters in hull gel coat. How do I fix?

Is it a structural thing or can I just ignore it?

Re: Blisters in hull gel coat. How do I fix?

Not structural. Is this a Saltwater boat?

Re: Blisters in hull gel coat. How do I fix?

Hey there. No iti is a freshwater boat. We keep in the water usually until the end of October or the first week in November. I just replaced the transom and it's hitting the water for the first time since last season. Dropping her in tomorrow night

Re: Blisters in hull gel coat. How do I fix?

Well, that kind of explains the blisters. This will help you understand the issue.
http://boatsafe.com/nauticalknowhow/1220983tip.htm

Re: Blisters in hull gel coat. How do I fix?

That link sort of over simplifies the repair process.

There are times when blisters can be localized (many reasons I won't go into now), but typically the entire hull surface will eventually blister, the ones you can see in the beginning are just the first ones to make themselves known. So just repairing the ones you see is only a temporary band aid, these repaired blisters will be surrounded by more new blisters before too long.

The correct method is to have the gel coat and the first few layers of affected glass removed from the entire hull, not just doing spot repairs, there are gel coat and laminate peelers made for this purpose. When the hull is as dry as you can get it, which can take a very long time, you can then rebuild the surface with epoxy and glass. The entire surface then needs to be faired and painted.

The cost of this type of repair is very high, so it’s normally only done on high end large boats.

Re: Blisters in hull gel coat. How do I fix?

ondarvr said:

That link sort of over simplifies the repair process.

The cost of this type of repair is very high, so it’s normally only done on high end large boats.

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Very VERY high costs in fact !

That kinda thing is not normally done DIY.. there are many aspects and windows that you need to follow.

DIY help on this kind of procedure is not common on any forum anywhere.

Blisters are not structural per say. They are like ants in the house .. as long as you can live with them you can get by. Some ARE structurally increasing the event of a break through. ( I have seen 3' ( FOOT ) blisters on bottoms ) ..

Bust out a few grand if your trying to sell the house though ..

YD.

Re: Blisters in hull gel coat. How do I fix?

LIke I said, Help you UNDERSTAND the issue. I guess I should have/could have said it was not intended to be a tutorial on repair. Thanks for the follow up guys. Did not mean to be misleading.:redface:

Re: Blisters in hull gel coat. How do I fix?

i have a 12 year old carver with 4 hull blisters the boat used to be in a wet slip. I sanded off my bottom paint opened them up ground them down and spot repaired them. After that I repainted the hull and moved the boat to dry storage. I have had no more problems with blisters so far. Also before you accuse me of a cover up I plan to make the next owner when I sell fully aware of the blisters.

Re: Blisters in hull gel coat. How do I fix?

Tagerman said:

i have a 12 year old carver with 4 hull blisters the boat used to be in a wet slip. I sanded off my bottom paint opened them up ground them down and spot repaired them. After that I repainted the hull and moved the boat to dry storage. I have had no more problems with blisters so far. Also before you accuse me of a cover up I plan to make the next owner when I sell fully aware of the blisters.

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If you had 4 blisters on the entire hull its not likely you have a blistered hull like we are talking about, 4 would indicate an isolated problem affecting just those spots. There is a chance you caught them at the very beginning and these were the only visible ones though.

Typically it would be difficult or almost impossible to count the number of blisters on even a few square foot section of hull when it’s osmotic blistering.

Re: Blisters in hull gel coat. How do I fix?

yeah I had 4 larger ones probably at inch across they were blisters because they had a little water in them but I do not have the tons of tiny blisters. I was told they could be from the boat sitting in the water while needing the bottom repainted bad but I don't know much about them other than they were ugly and I wanted to fix them.

Re: Blisters in hull gel coat. How do I fix?

The blisters are tiny, about 1/8 to maybe a 1/4 inch in size. I'm going to just leave it in her slip for the rest of the season. I'll take pictures when I pull her for the winter. If I don't sell her first. We've been looking at bigger boats at my marina. My marina offered me $10k trade for her with the trailer. I'm thinking that after my transom adventure I should probably take it and run. It's a beautiful boat but we need more room so maybe it's time.

Re: Blisters in hull gel coat. How do I fix?

I too am itching for a bigger boat and I haven't had mine for very long. I will say I personally would not worry about the hull blisters.

Re: Blisters in hull gel coat. How do I fix?

Regardless whether your boat is in fresh water or not , bottom paint is a must, fiberglass is porous and once the gel coat is breach/damaged or cracked you open the hull up to blisters and they will spread no stopping that. I agree with some of the other comments, it is an all or none type job, if you found some generally there will be more, many think if they are small not too bother with them. They can be left for along time but if monitored or one can fix them right

I have looked into it and read alot, my 250SE Doral is in the process of having the hull from beneath the lower pinstriping and down sanded down and repaired to deal with blisters that were there, the bottom of the hull is in good shape but at the water line to the port starboard side there was blistering at the water line and below.

It is also wise to check screws at the trim tabs, this is an entry point for water especially if these are not sealed caulked right and should be checked every couple years, a tip i was told.

Watch the video below from the 2 minute point on. Process is basically sand the hull down, let it dry out fully weather and temp dependent, I am waiting a week to let it dry w heat applied, Epiglass HT9000 resin or equivalent to seal fill replace the sanded/damaged areas to hull spec depth, Next is the Interprotect 2000E Marine Barrier coat kit, then Primer w Interlux Primocon Underwater Marine Primer and following I will do 3 coats of anti fouling 2 w Pettit Horizons (first blue then black) and last coat will be Micron CSC for final coat .

http://www.wholesalemarine.com/p/IL...tml?utm_medium=cse&utm_source=nextag#readmore

I will be spending some good coin but I will be owning the boat for 5 yrs at least and it will be in salt water 24/7 so I want this done correct. Once all completed a nice cut polish top to bottom as well!!

Re: Blisters in hull gel coat. How do I fix?

ciscokidd said:

sand the hull down, let it dry out fully weather and temp dependent, I am waiting a week to let it dry w heat applied, Epiglass HT9000 resin or equivalent to seal fill replace the sanded/damaged areas to hull spec depth, Next is the Interprotect 2000E Marine Barrier coat kit, then Primer w Interlux Primocon Underwater Marine Primer and following I will do 3 coats of anti fouling 2 w Pettit Horizons (first blue then black) and last coat will be Micron CSC for final coat .

I will be spending some good coin but I will be owning the boat for 5 yrs at least and it will be in salt water 24/7 so I want this done correct. Once all completed a nice cut polish top to bottom as well!!

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Interprotect 2000 is the barrier coating.

Sand your hull with 80 grit .. apply 4-5 coats of IP2000 .. apply 2 coats of bottom paint within the window allowed and there is no going from IP/Primer/Pettit/micron.

Just go from IP2000 to Micron and done ( or any other interlux brand bottom paint .. I personally like VC-17 ).

YD.

Re: Blisters in hull gel coat. How do I fix?

Yacht Dr. said:

Interprotect 2000 is the barrier coating.

Sand your hull with 80 grit .. apply 4-5 coats of IP2000 .. apply 2 coats of bottom paint within the window allowed and there is no going from IP/Primer/Pettit/micron.

Just go from IP2000 to Micron and done ( or any other interlux brand bottom paint .. I personally like VC-17 ).

YD.

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I stand corrected as your right, the Interprotect Primer is not needed,

Explain to me why Epiglass HT9000 as I mentioned is outlined in the video at the 3 minute mark followed by the Interprotect 2000E barrier coat kit as the following step? (I am new to this but learning quick and just want to clarify a few things and determine if I need to follow that route)

Is it a step recommended depending on the severity of your osmosis? If minor I am assuming it is not a required step but I would assume it is a worthwhile but not required. I am opting to go with West Marines re-branded Pettit Horizon (which in Canada this particular version was released late May 2012) and has had decent reviews, it is a self polishing ablative anti fouling paint I will use for the first 2 coats, the 3rd coat I plan to use Micron CSC which has the biocide agent within it that we can not get in Canada which will aid in slime reduction.

The VC-17 looks to be some nice anti fouling paint but is pricey, I went a little less expensive route.