Osmosis Blisters - Spot Repair?

[Cruisin Cat]

I had osmosis blisters spot repaired on the topside of my boat and now, 18 mths later, about 10% of the original blisters have reappeared....no "new" blisters, all the reappeared blisters are in the repaired areas.

So I guess my question to people who have done this sort of repair is....is it normal for blisters to reappear more or less exactly where the original repaired blister was?

Or....is this the result of poor workmanship in the spot repair?

[Ex-Calif]

Short answer - They should not reappear.

Longer answer - Not knowing what you had to start with and how it was repaired makes it difficult to simply say, "poor workmanship." But if it was a professional yard and they were told to eliminate the osmosis, one could argue they didn't do it right.

[AnchorageGuy]

If a blister repair is not done properly, it will most certainly reoccur. The area must be dry enough for the repair to be done correctly. If there is still moisture in the gelcoat or fiberglass blisters will return. Chuck

[a64pilot]

Isn't there the time element? I'm in a hurry and can't wait?
If that was the case 10% ain't bad? Although I think if they yard needed to let it sit longer that should have been explained.

[transmitterdan]

Can you have osmosis on laminate that is not wet all the time?

[a64pilot]

Originally Posted by transmitterdan

Can you have osmosis on laminate that is not wet all the time?

I haven't, but have been cautioned on leaving a welcome mat out as it can cause
blisters, so maybe?

[Cruisin Cat]

Originally Posted by transmitterdan

Can you have osmosis on laminate that is not wet all the time?

Yes you can (as evidenced by my boat!)

[Old Snipe]

Are these blisters the the repaired ones, or are they new blisters that have formed since the repair work was completed?

[Cadence]

Originally Posted by Cruisin Cat

I had osmosis blisters spot repaired on the topside of my boat and now, 18 mths later, about 10% of the original blisters have reappeared....no "new" blisters, all the reappeared blisters are in the repaired areas.

So I guess my question to people who have done this sort of repair is....is it normal for blisters to reappear more or less exactly where the original repaired blister was?

Or....is this the result of poor workmanship in the spot repair?

My stupid guess would be not thoroughly ground out or dried? Wait did you say osmosis blisters topside? Do you mean hull or deck? I'm speculating you mean deck and you are speaking of a delamination problem with a core rather than osmosis? More specifics will probably get you some good response.

[Cruisin Cat]

Originally Posted by Cadence

My stupid guess would be not thoroughly ground out or dried? Wait did you say osmosis blisters topside? Do you mean hull or deck? I'm speculating you mean deck and you are speaking of a delamination problem with a core rather than osmosis? More specifics will probably get you some good response.

Sorry about not providing sufficient detail.

The blisters were all over the hull, ie all of the area below the joint line (approx 1.5m above dwl downwards).

About 18 mths ago the manufacturer paid to have the area below dwl peeled, reglassed and epoxy coated and this seems to have worked well....at least no blisters yet, touch wood!

The manufacturer would pay for only spot repair above the water line and this is where the blisters have reappeared. However the interesting thing is that no "new" blisters have appeared, ie no blisters in new areas. All current blisters have re-emerged at the site of an old repaired blister. The other interesting thing is that approx 90% of the previously spot repaired blisters have not re-emerged (so far!).

Barrie

[Cruisin Cat]

Originally Posted by Old Snipe

Are these blisters the the repaired ones, or are they new blisters that have formed since the repair work was completed?

I had a full osmosis peel, reglass etc below the waterline and osmosis spot repair above the waterline. When the boat went into the water 18 months ago there were no visible blisters.

There are currently no visible blisters below the waterline.

The current crop of blisters, ie the ones that are currently on my boat, are all above the waterline and have all developed in the last 18 months. Also, these current blisters are all at the sites of previously repaired blisters. I estimate that blisters have re-emerged at approx 10% of the previously spot repaired blister sites...the other 90% of spot repaired blisters have not re-emerged (so far!)

Barrie

[Cadence]

Originally Posted by Cruisin Cat

I had a full osmosis peel, reglass etc below the waterline and osmosis spot repair above the waterline. When the boat went into the water 18 months ago there were no visible blisters.

There are currently no visible blisters below the waterline.

The current crop of blisters, ie the ones that are currently on my boat, are all above the waterline and have all developed in the last 18 months. Also, these current blisters are all at the sites of previously repaired blisters. I estimate that blisters have re-emerged at approx 10% of the previously spot repaired blister sites...the other 90% of spot repaired blisters have not re-emerged (so far!)

Barrie

I have no idea about the brand an how old the vessel is. I'd keep on them.

What is it, the squeaky nut gets the oil?

That info. might help someone else to avoid a similar problem.

[contrail]

FWIW, Fountaine Pajot has had quite a history of blistering.

[RickDelaune]

Hey Crusin Cat,
You need to check with the manufacturer. Sometimes when a boat comes out of the mold or if it is a custom one-off there may be fairing putty applied to the surface area. If the thickening medium is talc based, then there is a good chance that water will be absorbed by the talc since it is porous and you will wind up with blisters. Even if you repair the area the talc that is still on the surface will continue to Blister, above and especially below the waterline. If you can keep the water out, such as epoxy barrier coat, etc, then the problem should go away. If the boat was built with fire-retardant resin the antimony trioxide will act just like the talc and cause blisters above and below the waterline. Hope this helps, Capt. Rick Delaune

[19 and counting]

There are blisters and there are BLISTERS! We had to rip off the entire bottom of a Defever built in a not so great yard in Taiwan. Boat was out on the dry for two months, we even used a vacuum and bags tapped to the worst spots to help draw out the water.
This was definitely an issue that could impair the integrity of the hull. Then there are "sun" blisters that often occur at the waterline, we just ignored those. They were tiny and on our current boat with the thick '77 layup the little ones pose no great concern. On a boat that old it is not a big deal. If they were large blisters we would have walked, after our experience with the Defever. Conclusion, stay away from old cored hulled boats! Even the Defever with her extensive problems was old enough that the original inner and outer fiberglass on the cored hull was so thick it probably compares to modern newer lighter layups with just the interior shell being so thick. So depends on the boat, the age and the original process of creation to decide how seriously you want to go after those blisters.