Thoughts on Blisters

I did a full blister repair a few years back.....you can read about it and see photos of the job here

Boat Hull, Gelcoat Blisters and Hydrolysis

marinetrader said:

I did a full blister repair a few years back.....you can read about it and see photos of the job here

Boat Hull, Gelcoat Blisters and Hydrolysis

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Hey Mike – Simply excellent! Thank, You!!

That is the most succinct, simplest, fullest, and easily understandable “to the point” pictured-explanation of blister repair and bottom fiberglass repair with barrier coat and bottom paint refurbishment I’ve read... and, being an active boater as well as an avid self-repair boat person for decades - - > I’ve read a lot.

I ask permission to copy your “article’ so I may pass it on to other boaters who come in need of a clear path for best addressing blister problems they encounter. Of course, if you’d like, the copied and sent article of yours could have your name and company name as credit... I’d also be happy to include your contact #’s if that pleases you.

Let me know your desire on the above... I’ll not pass it on until I have your permission as well as instructions for including you name and various contact numbers.

Happy boating Daze! - Art

Art, feel free to pass it along and of course, a Company name with a website link would be appreciated

When you sell hammers, every problem is described as a nail.

marinetrader said:

Art, feel free to pass it along and of course, a Company name with a website link would be appreciated

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TY, Mike... will do so as other boater’s "blister" repair and bottom refinishing questions/needs come to my attention. Your name and numbers are on a folder page I would attach to an email or other relevant communication venue. Happy Holidays and a Great 2013 to you and yours Cheers! - Art

When you sell hammers, every problem is described as a nail.

And to a surgeon , even a headache is cured with a knife!

I posted earlier in this thread because we had some dimples in the botttom. When i broke them they bled clear stuff that had the telltale winegar smell. So i did the bottom job, sanded to gelcoat and it was all smooth as silk.let the boat sit over the winter outside while working on it. Now the boat is hauled out for winter and I had a tight look at the bottom... Nothing.. No dimples nothing out of the ordinary.

So for us it was bubbles within the bottom paint layers, there were many different types of paint mixed and many many old layers. After one season with four layers of barrier coat + one hard + one ablative layer everything is fine. I am officially satisfied.

I have also had these "bubbles" between paint layers from time-to-time.
Just happened that the last time was during a hull survey while the bottom was being pressure washed. The surveyor wasn't surprised given the age of the boat. His suggestion was to media blast the bottom of the boat and start over again if they were extensive. When you get four or five layers of different paints, this is not unusual. They are not "blisters" per se, as long as they are not under the gel coat.
So not to worry!!

Blisters or paint blister

When we hauled the boat today I discovered pencil eraser sized bumps/bubbles on the bottom. I haul every two years and keep the boat in the water year round. I didnt have the problem two years ago. This thread has lots of info but I cant determine if these may just be bottom paint blisters. The bubbles do not seem to be the dime and quarter size that others have spoke of in the thread. The boat was barrier coated in 2003 1 coat epiglass, 6 coat interprotect 2000, 1 coat bottom RED, 2 coats Micron CSC Interlux Blue.
Can anyone give me any thought on these.
Dave

From post 84....

"When your blisters are ground out, can you get a sharp chisel point into some of the layers?...if they separate / peel off with relative ease...I'd keep going...of ask an expert to take a look.

I kept going (at least 2 trash cans full of matt and roving I was able to peel/chisel off) before finding meat all around....if it all seems solid...you might be good to go. I sanded/ground past the gel coat on the whole boat to make sure my epoxy had a solid, clean surface to cling to. Most older gel coats are useless below the waterline as it does not restrict water migration as many think...it's just there for the showroom. "

If you have any other specific questions please feel free to PM me.

fryedaze said:

The boat was barrier coated in 2003 1 coat epiglass, 6 coat interprotect 2000, 1 coat bottom RED, 2 coats Micron CSC Interlux Blue.
Can anyone give me any thought on these.
Dave

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When I hauled for paint a while back, I had what looked like those as well. Luck would have it I had a surveyor standing right there. My heart was in my mouth. But he walked over with a pen knife and pealed one. . . water ran out, but there was bottom paint underneath it. It was also Micron CSC, he said my old paint wasn't compatible with the Micron CSC. He was right. . . as it dried over the weekend, it started cracking and peeling off all over. We ended up using garden hoes to scrape it all off. A bit of work but it came right off and gave us a nice clean surface to paint.

No more CSC for me!!

Have someone take a look at it and they can tell right away if it's truly blisters or just paint blisters.

Be careful who you trust to answer that...most surveyors know as little about blisters/hydrolysis as electrolysis/galvanic issues.

Question: Are blisters a concern when the hull is solid fiberglass with gelcoat covering? Am ignorant on the issue.

Believe what you want...I learned the hard way...it's not common...but any boat that has lived in warm water can be a candidate....

I recommend you do your own common sense survey:

Using knife, awl, and flat screw driver or small wood chisel: Pop a few in each area where the blisters are and scrape down (and around the blister by a couple inches) to the gel coat to really see what is underneath the blistered paint. Common sense will quickly tell you if the FRP underneath has been compromised by water intrusion.

If it has not been compromised... all you need do is clean up the “paint” blisters; then repaint. If it has then you should explore deeper into the fiberglass to determine to what extent intrusion has occurred. Get an expert’s opinion if you feel it necessary.

Seeing as you say it was not showing two years ago, and it seems by the rest of your post #99 that you have had boat for some time and not seen these pencil eraser sized blisters previously, it appears your “blister” problem is at least mostly paint related.

Good Luck!

dwhatty said:

Question: Are blisters a concern when the hull is solid fiberglass with gelcoat covering? Am ignorant on the issue.

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Blister(s) can become big problem if water intrusion into FRP fabric mesh makes it very saturated by water migration, especially over a long period of time. That said, not all blisters in gel coat are necessarily going to become a very big problem. It depends on how well the fiberglass was laid up in first place. e.g. multi layered fabric mesh fully saturated with good resin to create a thick resilent hull. Caught early on and repaired correctly could save headaches in the future!

psneeld said:

Believe what you want...I learned the hard way...it's not common...but any boat that has lived in warm water can be a candidate....

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ps - I've seen picts of yours before and read your story. Those are mean assss blisters. WOW!!!

Go way beyond TF advice...if I had followed it I would have been way off base.

You don' know until you check thoroughly...that's what the experts in the field say and don't believe much of what you hear from the boating community...research FRP tank and piping industries with a long history of paying big bucks to identify and remedy problems.

Sure common sense works great if you and the people eyeballing the problem have lots of experience in that area.

Dave, where was the boat prior to your last haul out? Was it is saltier water? I have seen boats moved to fresh or brackish water develop blisters that never had them before. Do you have an epoxy barrier coat under the paint?

Moonstruck said:

Dave, where was the boat prior to your last haul out? Was it is saltier water? I have seen boats moved to fresh or brackish water develop blisters that never had them before. Do you have an epoxy barrier coat under the paint?

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Its been in the Chesapeake bay for five years. Yes it was put on in 2003

fryedaze said:

When we hauled the boat today I discovered pencil eraser sized bumps/bubbles on the bottom. I haul every two years and keep the boat in the water year round. I didnt have the problem two years ago. This thread has lots of info but I cant determine if these may just be bottom paint blisters. The bubbles do not seem to be the dime and quarter size that others have spoke of in the thread. The boat was barrier coated in 2003 1 coat epiglass, 6 coat interprotect 2000, 1 coat bottom RED, 2 coats Micron CSC Interlux Blue.
Can anyone give me any thought on these.
Dave

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I you did a proper barrier coating of several undiluted layers you don't have blisters you have bottom paint bubbles. A big problem with barrier coating is people add solvents to the interlux to make it easier to put on which defeats the whole purpose of bottom coating. The idea is to apply a barrier with very little solvent, which is what caused the problem in the first place, but the interlux is difficult to apply. Havent done any for several years and I'm sure the new formula has improved
Good luck....I hate blisters

fryedaze said:

When we hauled the boat today I discovered pencil eraser sized bumps/bubbles on the bottom. I haul every two years and keep the boat in the water year round. I didnt have the problem two years ago. This thread has lots of info but I cant determine if these may just be bottom paint blisters. The bubbles do not seem to be the dime and quarter size that others have spoke of in the thread. The boat was barrier coated in 2003 1 coat epiglass, 6 coat interprotect 2000, 1 coat bottom RED, 2 coats Micron CSC Interlux Blue.
Can anyone give me any thought on these.
Dave

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I cut out a few blister today. I dont think its a paint issue. The area was damp inside. The pictures show spots about half the size of a dime. I shot them very close so I could inspect the details by blowing them up. So much for the barrier coat in 2003. The fact that the boat was barrier coated was a big selling point for me when I bought the boat.
Dave

Most barrier coats are done by the uneducated...I've seen several marinas do them and I wouldn't let those marinas row my dingy from one dock to the next.

The fiber ends you see in the blister are probably from the mat layer under the gel coat. You can see the same in my pictures ...and if you are daring...grind down far enough and you can peel off large strips by hand...

Sary but it's what happens to some of those 70-80's vintage boats built by a 3rd world nation with barely enough adult supervision.

Some boats are fine and many aren't...till you destructively test...you CAN'T know for sure (and the top yards that I have contacted/dealt with concur....

I know what my hull is like at every layer...do you??????

Hi Dave

I am very sorry for you to learn the small blister protrusions have revealed deeper problems into your hull bottom... Uplifting items I mentioned previously, regarding hopefully it was only paint and not fiberglass bubbles, were to keep your spirits up! Soooo, being a person that always looks to find the best, but plans for alternative measures if per chance the worse, worser, or even the worst were to arrive, I can simply recommend you do as psneeld did to his bottom – tear into each location it until you reach solid materials. On an again hopeful note, I surely wish you best luck in finding not too much water intrusion.

Repairing the damage is a whole other world of events/facts/knowhow. I'm confident psneld can offer great guidance for your material restoration.

You will find a plethora of repair info on the web. Some is good and some not so good. I recommend you research fully and ask some pros what they recommend.

I’m going to send you a PM.

May Queen of the seas smile favorably upon your task! - Art

PS: Depending on your financial / time-constraint circumstances... Remember that you can simply apply minor patching and paint over again as you go another year... however, the blisters may further expand their hull intrusions.

If you have water in laminates....

You have a couple of options...especially now that it's barrier coated...even for those without barrier coats and just gel coat...

Hot pack and vacuum which is the quickest and the most costly...

Grind off the barrier (and or gel) and let dry for 6-12 months in a warm dry climate.

Hand grind till ever square inch of laminate you grind to is dry...and follow extensive prep and epoxy rebuild actions.

People who have "professional work" done that involves a lot less work usually wind up with a "lot less professional" a job.

Not a doomsayer...there are lot's of hulls with random blisters that can be fixed individually....but the are hull that are disintegrating (like mine was) and the PO and Surveyor were clueless...I did the research and have a solid hull now....but it was neither easy or if you have to pay for it cheap.

fryedaze said:

I cut out a few blister today. I dont think its a paint issue. The area was damp inside. The pictures show spots about half the size of a dime. I shot them very close so I could inspect the details by blowing them up. So much for the barrier coat in 2003. The fact that the boat was barrier coated was a big selling point for me when I bought the boat.
Dave

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From the pix its obvious they bought a small amount of interlux then thinned it down and called it good. Lots of boats done that way. When they do that some of the solvent gets trapped so it dosent dry which then cause the old resin to liquefy and that looks like what happened to your boat. The good thing is they should only be superficial. To do the fix right you need to grind them out if they are wet then heat lamp the bottom to dry it out before making proper repairs. I have known people that have just kinda broke em open then dryed it a bit before patching each spot then bottom paint. Then each haul out they fix the new ones that pop out. I know its expensive but just bite the bullet and get the job done properly according the factory specs and be done with it. Best wishes

PS: sorry to hear your having to go through this. Slovenly work is a pet peeve of mine

Commiserations Dave. I don`t doubt psneeld`s optimal options,(#115) and I lack knowledge of how the barrier coat adds to the problem. That someone decided to barrier coat the boat suggests there was a problem emerging, but that is conjecture.
My repairs in 2011 were done over 4 weeks in conjunction with other work. Each blister was deep concave ground until the wetness stopped. Judicious heat was used to promote wet oozing. Eventually each dry crater was filled with layers of mat and epoxy. At the time there was evidence of prior repairs, few if any of the blisters were recurrences. At haul out 2 years later all was well, no fresh ones, no recurrence, compliments on the hull condition from the shipwright. (Note the IG hull is about 1" solid f/g.)
Hard to say what is the best move, it might be worth fixing what`s there, and seeing what develops, rather than a full peel and rework. Soda Strip is popular here, as my work proceeded the guys doing it and I decided we should(using 20/20 hindsight) have gone that route. Especially if the barrier coat has to come off. Good luck.

I know nothing about the technical aspects of blisters nor do I personally have the experience to evaluate them. However, they seemed especially common on the lake I grew up on and it was attributed to the chemical content of the water accelerating whatever underlying issue there was. I also found out that there are a few people who are really expert in evaluating them and a lot who know very little but think they know a lot. Find one of the former and don't guess. At the worst case it's really rather simple as I've seen those that you could poke through and go deep into the hull, basically through it. The worst of those I ever saw was due to a bad lot of resin delivered to the manufacturer, immediately acknowledged and the boat exchanged. I've seen some on boats that appeared benign until the expert examined more and found them to contain quite a bit of moisture. Then I've seen those that were described as completely surface, likely paint issues. I once heard one person describe them as the equivalent of hail damage but on the bottom. So take plenty off the value, require a lot of work (including scraping and new paint job) but don't impact structural integrity at all. New one person he told to just wait until he otherwise needed his bottom painted and last I knew he'd been seven years more with no problem.

There is nothing that makes me reach for a bottle of red and a corkscrew faster, than talk of blisters.

Sarawana has blisters, always has had from what I can gather. She is 33 years old & not in danger of sinking, or from what I can gather, ever likely to be in the next 33 years.

You can buy an awful lot of nice shiraz for the cost of a blister bottom job.

Andy G said:

There is nothing that makes me reach for a bottle of red and a corkscrew faster, than talk of blisters.

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Especially the kind that respond to penicillin.