Blisters, again

[a64pilot]

Did search, found several threads, most are about much more serious problems than I believe I have

Surveyed an 87 IP 38 yesterday, she has blisters, well not real blisters like I've seen before this is sort of a localized "pox" .25" blisters, some seemingly through the gel coat, maybe half? Anyway there seems to be groupings of these little blisters, maybe 25% total hull coverage, maybe less.
Boat will get a bottom job soon as it's due. I'm not letting these stop my purchase, just seeking advice on what to do with them. Also found a small section of Delam in the keel about the size of a deck of cards without water intrusion, plan to have that ground out faired and re-filled?
Boat has been kept and will be kept year round in warm water. Surveyor's opinion was that when the barrier coat was applied three years ago, hull was not allowed to properly dry out and the barrier coat is what's responsible for this rash of little blisters.
So what to do with them? I'm of the opinion that a peel is overkill, even if I had that kind of dough, so grind em out, fill them with what, thickened epoxy maybe? Or leave them alone and deal with them on the next bottom job?
I'm leaning that way, by that time I will be more experienced and possibly know more people around my local area etc., but I do NOT want to delay something only to have it bite me and they be much worse and harder / more expensive to deal with.

[Capex]

Suggestion: Just grind them out (if they are small) until no more wetness is showing around the edges of the ground area, then refill with Micro balloons and epoxy (easier to sand). If the hole that has been ground starts to go into the first layer which will be CSM (chopped strand mat), then you must back fill with a layer(s) of CSM. If the hole goes into the underlying glass (e.g. woven roving/Eglass) then you must relayer with the same glass as has been ground out. In all these instances you must use epoxy resin as new polyester does not adhere to old polyester very well.
Sorry if it sounds like I am trying to teach grandmother about sucking eggs but I don't know your level of expertise so apologise if I am out of line.

[HappyMdRSailor]

Wowsa...

First post from Capex is a somewhat detailed procedure on blister repair???

WELCOME TO CF Capex!!!!
You're going to fit in GREAT HERE!!!!

Pilot... I'm with your guy here... I think the rolled on a barrier with a wet hull.... That SUCKS!!! Coulda been a great thing, but turned into a bad thing do to inexperience, impatience, ignorance, or simply.... "get this job outta my yard so I can get paid-ism"

Here's my take.... The barrier is there... You've got water trapped on "both sides" one good, one bad.... BUT.... BUT... BUT.... There shouldn't be any more water passing the barrier... or at least incredibly slowly....

So... My advice??? Leave it and go sailing.... Deal with it in your own back yard a year from now... Well... 9 months from now when it's WINTER AGAIN.... Fix the delam section now though....

The grind and fill will work great if the actual NUMBER of blisters is manageable.... less than 100??? gravy.... 200??? ok... lotsa work.... 350??? start to think another method... 1000??? peel.... IF they are superficial... AND I THINK they are... you may get away with grinding larger thin areas instead of individually.... epoxy/cabo fill, epoxy/micro fair, barrier, paint....

Let's readdress the method when we see a few ground out... Bet there's no glass cloth needed...

Congrats I hope!!!! She'll be worth it!!!

Pictures of the new ride PLEASE!

Oh... and the hull blisters too....

[lancelot9898]

I'ld find a surveyor who can do a laminate profile so you know exactly what layers are involved. I had blisters on my boat and I found that I had 3 layers of CSM between the gel and the glass roving. That outermost layer of CSM was extremely wet and was the source of the blister formation, however, there was not a safety issue and it could be left alone. However I did go with the peel and all the associated work to apply the barrier coats.

[Capex]

Many thanks for the welcome HMRS. Been a member for some time but just thought that this one needed a reply on a subject which I am familiar with. I have been in the marine industry for the past 30 years.

[Capex]

Originally Posted by lancelot9898

I'ld find a surveyor who can do a laminate profile so you know exactly what layers are involved. I had blisters on my boat and I found that I had 3 layers of CSM between the gel and the glass roving. That outermost layer of CSM was extremely wet and was the source of the blister formation, however, there was not a safety issue and it could be left alone. However I did go with the peel and all the associated work to apply the barrier coats.

I was replying from the perspective of a surveyor as I am one.

[lancelot9898]

Well...have you done a laminate profile?

[GordMay]

Greetings and welcome aboard the CF, Capex.

[HappyMdRSailor]

Originally Posted by Capex

Many thanks for the welcome HMRS. Been a member for some time but just thought that this one needed a reply on a subject which I am familiar with. I have been in the marine industry for the past 30 years.

You bet! Tons of experience will be perfect for all the disagreements on opinions that are sure to come....

Originally Posted by Capex

I was replying from the perspective of a surveyor as I am one.

[a64pilot]

Capex,
Thanks, if I knew what I was doing, I wouldn't have needed to ask. I know just enough to be dangerous.
I'll try to do a pic thing just gotta figure out how

[robert sailor]

Been there done that.

My bet is that the blisters just keep reappearing as time goes on. I had a very similar situation on one of my boats and I did the grind the blisters/fill/fair/epoxy and every year or two when I pulled the boat they were back. Like yours they were all small and were in the first layer behind the gell coat, some penetrating a little deeper and someone earlier had done a barrier coat. Depending on where your sailing, the warmer the water the more you get. Too me one either lives with it and hopes they stay small or blow your brains out on a peel job. I have had very little luck doing local blister repairs. With boats built with polyester resins its not abnormal as the vessel ages.

[Capex]

For what reason would you require a laminate profile? The profile of the original builder has long been trodden into the workshop floor. If you understand how laminates should be laid up, then you don't require any such profile. The first layer against the gelcoat must always be CSM to prevent print through and the next layer will your chosen fibreglass i.e. woven roving, Uni directional/bi-directional/tri-directional knitted E-glass or what ever. There must always be a layer of CSM between each layer of glass that is in the lay up. As you grind through each layer you will see for yourself what the builder has used in his lay up and the deeper you go, the wider you have to bevel the spread of your replacement layers. Each layer must be wider than the last. CSM does not provide any strength but is a binder and filler rather than anything else.
Sorry to sound pedantic but if its not done right, it isn't going to work.

[a64pilot]

Pics of blisters, notice this side of the boat is almost free evcet for th ebow, but towards the stern there is another rash of them. The slightly larger circle 3"x6" is the dealmination

[a64pilot]

Admiral at the helm, she doesn't look unhappy, and she is the one who I have to make happy

[Capex]

Just my opinion, but I have seen this on many boats and it is not a big problem. Just grind them out as they are very superficial, fill and fair and repaint. In my experience with polyester boats, they will continue to appear annually in small number and unless they start to penetrate the substrate, are a minor irritation (unless left to their own devices!!). The worst instance are boats that have been built in Europe, sporting some very well known and famous names, and are now doing duty in the tropics (I live in Thailand).