Blister Photo & Question

[Cheechako]

Originally Posted by minaret

Personally I believe recurring blisters are often the result of the almost universal habit of dishing out a blister and then just filling it with epoxy filler and barrier coating over. We would never do this in our yard, it's just not proffesional (although many pro yards still do it this way because they have a short warranty and it's quicker). We dish out each blister and then ......... of course the hotvac.

A lot of truth to this I think. , if there is enough hull there then a good peel and a season on the hard may be the best fix. Not sure everyone is up for that though. The worst blister problem I had was a Rawson 30 built in 73/74. A few blisters were 6-8 inches long, the bottom of the boat didnt have one sq foot that wasnt blistered. I went through two iterations of repair, first one was dish out and fill them all with a month to dry. Followed by Interlux and then bottom paint. 1.5 years later the boat was just as bad as it started. The second time I did the same thing, except rolled on 2 coats of epoxy resin, 2 years later when I sold the boat there wasnt one blister on it at survey..... So it can be done. Why not peel? the hull wasnt thick enough! Some blisters were 3/16" deep and the hull was about 3/8"! This was obviously an "oil crisis" boat, built thin with questionable resin....

[casual]

OK Guys I,have read so many articles on Blisters I,have confused my self.I,whole heartly aggere with Minaret in his approach Glass out Glass in,I,have repaired blisters using this method,never had one return.NOW the big question when buying a boat upon haulout no blisters appear,how is a buyer,a surveyoror anyone know whats under the paint.

[gelcoatjeff]

Grind them open , let them dry for a few days . Fill them with two part epoxy and cabosil sand flush apply 2000E interlux primer , and then apply 2 coats of premium bottom paint. We do it all the time here in Florida and we have never had a redo from not one customer.

[bobconnie]

Maybe this is a stupid question, but has anyone seen a boat that sank from blisters ?? never owned a glass boat so this is a real question not a joke !! Ive seen some boats that are know to blister badly, still sailing many years after they saw the blisters ! Just want to know as we are looking at glass boats at this time !! how bout it Minaret ??

[Ex-Calif]

Originally Posted by bobconnie

Maybe this is a stupid question, but has anyone seen a boat that sank from blisters ?? never owned a glass boat so this is a real question not a joke !! Ive seen some boats that are know to blister badly, still sailing many years after they saw the blisters ! Just want to know as we are looking at glass boats at this time !! how bout it Minaret ??

Just a guess but probably a number of older boats with severe issues get parted out and ground up. Minaret is clearly the master of Osmosis but I couldn't stomach $10k+ to fix an old boat.

True sinkings not related to fire, unattended boat, or the occasional severe broach are pretty darn rare. Never heard a first hand story of a sinking.

[minaret]

Originally Posted by bobconnie

Maybe this is a stupid question, but has anyone seen a boat that sank from blisters ?? never owned a glass boat so this is a real question not a joke !! Ive seen some boats that are know to blister badly, still sailing many years after they saw the blisters ! Just want to know as we are looking at glass boats at this time !! how bout it Minaret ??

Nope, never seen a boat sink from blisters. But, as I have posted here before, I have seen boats declared a total loss by the insurance company due to severe hydrolysis and resulting delamination. Hydrolysis can have very bad results, as a little searching even here on this forum will show you. Here's a thread with some pics of member psneelds hydrolysis woes-


http://www.cruisersforum.com/forums/...ats-80550.html


The same sort of thing can certainly become severe enough that while it may not sink the boat on it's own, the boat would be unlikely to survive an impact it would have shrugged off before saturation and hydrolysis. It can also have a surprising effect on performance in some cases, saturated hulls can become pretty heavy, which while it's no big deal on a big heavy boat can be a real problem on a multihull or light monohull.

[Cheechako]

Originally Posted by gelcoatjeff

Grind them open , let them dry for a few days . Fill them with two part epoxy and cabosil sand flush apply 2000E interlux primer , and then apply 2 coats of premium bottom paint. We do it all the time here in Florida and we have never had a redo from not one customer.

I have personal experience on 3 boats which were bad to severely blistered. In all 3 cases your method was applied..... more than once. 3 times on one boat, 2 times on the other two. In all 3 cases the blisters came back. The permanent fix, (which I did on two of these boats, not the third) Was to strip to gel, blisters ground and filled as you mention, then West Systems Resin Epoxied with a roller, prior to primer and bottom paint. The blisters didnt return on either of these boats. Your method is definitely the prevailing method preferred by most boatyards. I can only conclude that often boatyards dont see their results a couple years down the road.... or peel in bad cases. But peeling has really only become comon in the last... 10(?) years.

[minaret]

Originally Posted by Cheechako

I can only conclude that often boatyards dont see their results a couple years down the road.... or peel in bad cases. But peeling has really only become comon in the last... 10(?) years.

Agree with that. Most yards have very short warranties, 2-5 years for blister repairs. They do this because they know perfectly well that five years is about how long it takes for the blisters to reappear when the method in question is used. So of course they don't see their clients again, because when the bottom blisters again a year after the warranty expires the owners are not likely to take it back to the same place. Our warranty is ten years, one of the very few ten year warranties left in the business. If we screw up a bottom it's coming back on us most likely. So we are careful to do it right. If you carefully read WEST system's literature, you will note that they are very clear about noy applying fairing compound in thickness' more than about 1/8", due to the risk of solvent popping. Most blisters are substantially deeper than this. This means the only way you can fill a blister with WEST properly is to apply filler 3-4 times, sanding between each one. That would take forever and nobody does it. Hence my belief that this method is a sucker job that dishonest boatyards use to con their clients out of money. Or at least that's how it started, now people have been doing it for so long that some appear to believe it is actually the proper method. Which always shocks me, don't know why anyone would think it's OK to remove a subastantial portion of the thickness of your hull laminate and replace it with filler. Completely destroys fiber continuity and in my opinion can definitely weaken the hull.

[Ironhorse74]

I just hauled today. I have what appear to be "blisters". Everyone of them has cracked paint. To me it looks like it is moisture trapped between the gelcoat and the paint. I opened several of the "blisters" The paint pops right off with a pocket knife leaving smooth fiberglass and gelcoat below it. Is this a true "blister" or just a case of poor paint adhesion?

[casual]

Bash Wht doese any boat built in 1986 have to have Blisters?Any othet troubled years? Just Curious

[Ex-Calif]

Originally Posted by Ironhorse74

I just hauled today. I have what appear to be "blisters". Everyone of them has cracked paint. To me it looks like it is moisture trapped between the gelcoat and the paint. I opened several of the "blisters" The paint pops right off with a pocket knife leaving smooth fiberglass and gelcoat below it. Is this a true "blister" or just a case of poor paint adhesion?

Sounds like a bad paint job.

Is it hard anti-foul? What type?

Got any pics?

[Ironhorse74]

Originally Posted by Ex-Calif

Sounds like a bad paint job.

Is it hard anti-foul? What type?

Got any pics?

I can take some pics tomorrow. It is an ablative copper bottom paint. It is on pretty thick. Unfortunately the gentleman I bought the boat from has Alzheimers. There are a lot of unknowns.

[minaret]

Originally Posted by Ironhorse74

I just hauled today. I have what appear to be "blisters". Everyone of them has cracked paint. To me it looks like it is moisture trapped between the gelcoat and the paint. I opened several of the "blisters" The paint pops right off with a pocket knife leaving smooth fiberglass and gelcoat below it. Is this a true "blister" or just a case of poor paint adhesion?

Sounds like poor paint ahesion. As long as the gelcoat looks good your fine, many years of stacked on bottom paint can do all sorts of chipping, flaking, bubbling, and peeling.Maybe try to scrape or sand a little section down to the gel and see what it looks like. Then you also have a paint free spot you can stick a moisture meter on if you have one.

[Ironhorse74]

Thanks Minaret and Ex-Calif I really do think it is a paint adhesion problem. As the paint was lifted off the gelcoat. Will sand it tomorrow.

[Nicholson58]

Originally Posted by Bash

The displacement/length ratio of a Valiant 40 is 255.56. According to the US Sailing calculator, linked below, that puts it in a "Moderate Displacement" category.

D / L Ratio

While you're there, you may want to do the math on the Kelly Peterson 44. It comes out at an even lower 230.17, which US Sailing also lists as "Moderate Displacement."

Just plain silly?

I suppose that makes us a super-tanker. 55,000 disp/58 feet = 948. We are a LLoyd's registered ship. (Camper & Nicholson 58).

We had pimple sized blisters at about 2 per square inch over the entire bottom. There were 7 blisters bubbled up under osmotic pressure up to about a foot in diameter max. We had the bottom blasted and then I used a carbide burr and faired out thousands of the gel coat failures. most of the gel pimples had bottom paint within their interiors and wicked into the surrounding dry glass. All were filled with West epoxy. After fairing we applied 5 coats of Interprotect. I would choose a peel if I had to start over. The boat was out of water 5 years from when we bought until it splashed. The big delaminations were ground out until the edges no longer weeped. I used West epoxy and many pre-cut layers of glass to fill the deep divits. Apply a layer of Saran or Polyethylene to help hold the patch as it hardens. Make sure there isn NO air trapped. My hull is solid and about 1 inch thick.

My photos link is below. The rudder was total trash with bad glass throughout. I totally rebuilt it in solid epoxy and microballoons with a carbon fiber skin. Now bullet proof. Eventually, I found US Composites to have great resins, fillers, and cloth at the best price.

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