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Bottom Blisters

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cch
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Initially Posted - 08/09/2003 : 11:06:53

I could use some advice on bottom blisters.

Up until five years ago we lived and sailed on mountain lakes in Colorado. Moonglade our C25 sr/sk was hauled each fall and spent the winter on the trailer. We are now in northwest Florida and Moonglage has only been out of the nearly tropical gulf waters a couple of times, for bottom jobs.

At the time of our last bottom job (about a year and a half ago) we noticed maybe a dozen to twenty small blisters about the size of a nickel maybe a quater with a slight protrusion. Everyone at the local boatyard where we were doing our bottom job said "just squeeze the water out, paint her up, get back in the water, and forget about it. That is exactly what we did, except for the forget about it part.

It is now time for us to pull the boat and convert from swing to wing keel. The boat will be out of the water for a week or two. My question is this: Is a week or two long enough for those blisters to dry out? Should I haul the boat now giving more time for the blisters to dry? (the new keel will arrive in about a month) In any case, once the current blisters have been properly dealt with, do I spend the time and money doing a barrier coat before applying the bottom paint after the keel retrofit?

These wonderful warm salt waters in Florida are fantastic for sailing but I need a little help learning to care for my boat.

Thanks,

Chris Hunsicker
Panama City FL
Moonglade
80 C25 #2126 sr/sk

Edited by - on

Gloss
Master Marine Consultant

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1916 Posts

Response Posted - 08/09/2003 : 11:29:55

When I had my 89 wk hauled and surveyed we noticed hundreds of small blisters. After I purchased her I had her on a trailer for a few months before putting her in my slip. the blisters went away. apparently they were in the bottom paint, not the gel coat.
Next spring I'll sand her bottom and put on a barrier coat before I paint. The 89's were laid up with vinylester resin to prevent blisters, but I figured that a barrier coat would be added insurance.

Warm water also will cause blisters faster than cold water.

Frank Gloss
89WK/TR

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RichardG
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Response Posted - 08/09/2003 : 11:52:55

Chris:

Since you have a trailor, you may want to pull the boat now, grind out the blisters and let them dry out as much as possible. I'm guessing you have a place to park it for little or no cost. I'm also guessing you need to significantly prepare the hull for the wing install anyway, which would mean preparing the hull for barrier coat might not be a lot of additional work. Make sure you mark the blisters immediately when you pull it, because blisters can shrink and dissappear pretty quickly (which doesn't mean they are not there).

Others who've done the wing retrofit may have different ideas.

My boat stays in the water year-round. While I've fixed many blisters on my fin keel boat each time I've pulled it for new bottom paint, I've never allowed the hull to dry out properly or done a barrier coat because yard storage fees are prohibitively expensive around here. Guess I'll just have to keep doing my blister repair routine every other year or so.

RichardG 81 C25 SR/FK "Sanity"

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cch
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Response Posted - 08/09/2003 : 13:03:56

[quote]
While I've fixed many blisters on my fin keel boat each time I've pulled it for new bottom paint, I've never allowed the hull to dry out properly or done a barrier coat because yard storage fees are prohibitively expensive around here. Guess I'll just have to keep doing my blister repair routine every other year or so.

Thanks Richard,

I may need to fix the blisters before allowing them to dry properly as well. What procedure do you use to fix them?

Chris Hunsicker
Panama City FL
Moonglade
80 C25 #2126 sr/sk

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tinob
Master Marine Consultant

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Response Posted - 08/10/2003 : 11:29:05

Chris,

When I had my bottom blasted it showed a gazillion pea size blisters. I contacted the Interlux people and followed their advice. This involved using a Dremel tool and burr to open the blisters and then after the prescribed period of time for drying used the Interlux products to putty-up the holes, then fairing them in preparation for barrier coating. It was a heck of a laborous job for an old timer but worth the effort in the long run. Incidentally this followed the retrofit of the swing to wing keel. The bottom has been blister free for 6/7 years now(fingers crossed).

Blisters that enter the roving require, after opening and drying them, to be treated with Interlux 1000 before puttying. This will be detailed in the Interlux booklet available upon request from them.

Best of luck with your upgrade.

Val on Calista #3936

Val Bisagni]<img src="http://im1.shutterfly.com/procserv/47b3df11b3127cce94709c5ff2e90000000010" border=0>

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RichardG
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990 Posts

Response Posted - 08/10/2003 : 12:39:33

Chris:

It may not be proper, but this is what I've done.

Day 1 --
1. Pull boat and pressure wash any growth/loose stuff.
2. Mark blisters with sharpie before they shrink.
3. Grind out blisters with angle grinder (4 1/2" version is about $18 at Harbor Freight Tools). Remove all "wet" or loose material on the inside, which is often a bit bigger than the blister shows on the surface. For a nickel size blister, the finished "bowl" may be about 1/4" deep and tennis ball-size round.
4. Sand the whole bottom with a random orbital sander or palm sander. Wear eye protection, respirator and full, throw-away sanding suit. I do the best I can, but don't come close to sanding everything off.

Day 2--
1. Wipe out blisters with acetone.
2. Brush ground-out blisters with pure epoxy (like West System), with no thickener.
3. Good to have a helper for this one to mix small batches of epoxy while you apply. Cut out a lot of patches/circles from fiberglass cloth, sized at or a little smaller than the blisters. While holding each fiberglass circle in a blister, brush it thoroughly with pure epoxy. Use ribbed type tool (looks like a meat tenderizer) to role out any air bubbles. Continue building up this way inside each blister which may take 5 - 12 fiberglass pieces.
4. Mix epoxy with thickener (I have used colloidal silica) to peanut butter consistancy. Patch each blister with plastic putty knife using this stuff. Go back and re-patch with this stuff any areas which have shrunk/sagged.

Day 3 --
1. Sand all patches until fair.
2. Tape water line with good, thick tape.
3. Wipe whole bottom with acetone.
4. Mix paint thoroughly. Two buckets are helpfull, pouring paint back and forth until all copper is completely consistant throughout (may take 25 pours).
5. Paint bottom with roller. Go back with remaining paint, covering as much as you can, especially waterline and leading edge of keel, but save some for tommorrow.

Day 4 --
1. While boat is up on the crane, wipe with acetone and paint areas which were under support pads. Try to delay the crane operator as long as you can before he drops boat back in the water.

If you have help, make sure lots of pizza and cold beverage of choice is available at all times during the process.

Day 5 (Note: you can skip this step if you wore sufficient protective clothing the previous 4 days) --

1. Go to doctor to get cortesone shot for treatment of reaction to fiberglass/epoxy/paint dust/mixc. toxic chemicals.

RichardG 81 C25 SR/FK "Sanity"

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cch
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202 Posts

Response Posted - 08/10/2003 : 16:11:13

Richard and Val,

Thanks to both of you for your input.

I am making plans to haul my boat as soon as possible in order to have as much drying time as we can find. Your techniques help me to better understand the work I am in store for.

Chris Hunsicker
Panama City FL
Moonglade
80 C25 #2126 sr/sk

Edited by - on

Gloss
Master Marine Consultant

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1916 Posts

Response Posted - 08/10/2003 : 18:07:55

I did a bottom job last fall. I cannot stress enough how important it is to have a good respirator. the cheap paper drywall masks are not enough. you need to buy a 3M respirator with the carbon cartriges. It will cost you about 40 bucks, but it will make a big difference in what respiratory problems you may get. It is cheap compared to how much you are going to spend on your bottom job. I also got a bosch random orbital sander and hooked it up to my wet/dry vac with a drywall dust bag placed inside the drum. That also helped keep the dust down. Don't forget eye protection too.

Frank Gloss
89WK/TR

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Gloss
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Response Posted - 08/10/2003 : 18:10:02

I forgot to mention that when I did my bottom job last fall a train derailed less than a mile upwind and released a toxic cloud of sulfuric acid. We got evacuated by the police. It wasn't pleasant at all.
I hope this doesn't happen while you are doing your bottom job.

Frank Gloss
89WK/TR

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OJ
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Response Posted - 08/11/2003 : 21:17:30

Chris,
Probably the best $3 I ever spent was on Gougeon Brothers manual titled Gelocat Blisters: Diagnosis, Repair & Prevention.

Good Luck

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cch
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Response Posted - 08/13/2003 : 00:35:36

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Chris,
Probably the best $3 I ever spent was on Gougeon Brothers manual titled Gelocat Blisters: Diagnosis, Repair & Prevention.

Good Luck
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

OJ,

Any Idea where I might find a copy? I tried amazon.com and eBay. Not many bookstores here in Panama City.

Thanks

Chris Hunsicker
Panama City FL
Moonglade
80 C25 #2126 sr/sk

Edited by - on

Gloss
Master Marine Consultant

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1916 Posts

Response Posted - 08/13/2003 : 07:15:06

go to the Gougeon website to order the book. Do a search for Gougeon, or WEST system. You will find it.

They also have free books too.

My only problem with the West system is dealing with the Amine blush. I'm looking for a system that doesn't have Amine blush.

Frank Gloss
89WK/TR

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