Blistering

[sailingdog]

JeffH-

I thought you were speaking of water-saturated...not resin-unsaturated laminate. Thanks for clearing that up.

[camaraderie]

Sonny...While there's been lots of great advice onn repairig blisters here...one thing you have to consider is that this is a 25 year old boat worth perhaps...$2k??
Aside from the hundreds of $$ of materials you will need to make this really right...there is a lot of unpleasant labor involved and you have to put some value on that. If the blisters are as extensive as you seem to indicate, I'd try to do a cheap and dirty job that will keep ya good to go for a few years before the boat is trashed. I would sandblast below the waterline, throw on a couple of coats of barrier coat and a couple more of bottom paint and just go sailing!
If you want to go for the right job...no problem...but I just thought I'd offer a contrary opinion! If you do decide to go ahead...check out thhis article on how you can do it without spending months waiting for the blisters to dry out:
http://www.epoxyproducts.com/blister4u.html

[TXS-ALAMO]

Has anyone heard of hotair vacume used to speed the drying process? I have seen a few cryptic references to vacume drying, but no details and it seems to be something beyond us DIYs.

[SunnySideUp]

Here are some pictures of the job ahead. As you can tail it is going to be along one. The bigger yellow box(the smaller of the two picture) is 1' square. The smaller yellow box (the bigger of the two picture)is a bubble if you will. It is about 2" across and 1-1/2" top to bottom and stands out about an 1/16 of an inch. I thank that water has gotten in between the layers of gel-coat and the glass to make this one. Anyway, it is going to sit for three mouths and dry out. I wrapped it up like a Christmas gift today. Just in time we got more rain this evening. Again thanks for all the help.

Sailnet Pic_2..jpg

Sailnet Pic_1..jpg

[Jeff_H]

Hi Sonny,

Unless you open the blisters there will be almost no drying of the laminate in that three month period. A partial cause of the blistering is that the outer raised surface of the blister isn't pourous enough to relieve the pressure building up, and so the pressure pushes the membrane away from the hull. With the membrane that forms the outside of the blister in place, very little water can pass through compared to with the membrane removed.

One minor suggestion, having seen the photos it would probably make sense to have a shallow peel and then grind out the deeper delaminated resin. On a boat like the Catalina 22, another suggestion, for what it is worth, it would sure be a lot easier to do the layup and grinding with the boat turned upside down.

Jeff

[SunnySideUp]

after the boat has been peeled and the blister have been sanded, how much time will it she need to dry out. How about on here side I'm not to sure I can get her turned over. I have to do it in a self service yard or in my on yard. The marina want allow you to do this kind of work in the dry slip. You have to do it in there yard and of course there is a daily charge.

[Jeff_H]

Much of the drying time is dependent on the the depth of the blisters, the amount of resin lean laminate that you encounter, the climate, and the overall thickness of the resin. In the case of the Catalina I would expect two months or so as a proper drying time.

Working with the boat upside down is much earier than right side up. Gravity is working with you rather than against you and the light is better. With keel out a roll over is pretty easy. Typically the DIY way of rolling a boat is to use a roll over rig, (two large plywood half circles that fit the hull and deck and which are braced to prevent collapse.)

Jeff

[pigslo]

Those pictures look just about like mine when I did it. I opened mine hith a Porter Cable sander with 60 grit paper.

Pigslo

[foxglove]

I think the cheapest way out of this blister problem is to grind off the blisters and wait for a couple months as Jeff said. Then mix some epoxy with colloidal silica until it has the consistency of jelly, apply it with a flexible 4 inch wide plastic applicator, then roll on one two more coats of epoxy.

Those blisters look just like the ones I fought with this spring. I had my boat sand washed but I could have used a grinder. I used MAS epoxy because I got it cheaper at Boaters World. MAS epoxies has a help line (and the co-owners take call on weekends from their cell phones).

I coated almost the entire hull below the waterline with the coloidal silica/epoxy mixture. That's how many blisters I had. The MAS people told me that the first coat of epoxy seals the hull; the next few coats help protect from deep scratches. I applied a total of four coats but you could probably get by with two; that would save money. Epoxy is expensive.

Like Camaraderie said, you don't want to sinik a lot of money into a boat that probably will never be worth much if you wanted to trade up to a larger or newer boat.

Max

[SunnySideUp]

Will it has been 3 1/2 months and I do believe it is time to start the work at hand. My only concern at this time is what type of tools I'll need. A grinder sounds like to much and hand sanding will take to long. What is in between the two, And orbital sander, a buffer with an 80 grit pad. If the lot of you have any input on this please Help.

Thanks.