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 do335 |
Hull Blisters |
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Posts: 257 01/06/06 16:05:05 |
I just had my boat pulled today and noticed aprox. 6 dime size blisters on the bottom of the hull. Several were on the side of the skeg in front of the rudder. I'm kinda surprised that a 1999 model boat would have blisters already. Anyone else seen this on boats this age? I'm planning on epoxying each blister after the hull is dry. Any other things I should do?
Steve 642-2f TESA
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melelana |
Blisters | #1 | ||
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Posts: 335 01/07/06 10:21:52 |
Steve,
Sorry to hear about the blisters. Sounds like there's just a few, they aren't too serious and don't have any structural implications. I've dealt with blisters on 3 boats. My last boat required a full peel and barrier coat. A friend's Grand Banks 42 had a scattering of dime size blisters. 2 years ago, I dealt with a number of small blister's on Melelana's rudder. I recommend you sand the bottom paint off in the area of the blisters and use a dremel tool/die grinder to open up the blisters now to achieve as much drying as possible over the rest of the Winter. You want to make the area slightly concave. In the Spring, sand the area agressively with 60 or 80 grit and fill the blisters with 3M vinylester putty. It's faster and easier than using an epoxy filler (goes on like Bondo) and fairs out well. After curing and sanding, coat it with West epoxy with barrier coat additive or Interlux interprotect barrier coat. I wouldn't go with a bottom strip and a complete barrier coat this season, but you might want to factor that into a future haul out. Good luck, Larry Melelana Catalina 42 #175 3 cbn,wk Solomons MD |
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do335 |
Re: Blisters | #2 | ||
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Posts: 257 01/07/06 21:48:09 |
Larry,
Thanks for the advice. Here in California we leave our boats in the water year round so it will be going back in next week. I checked all the blisters today and found that once the blister was popped, it was dry very quickly. I think I will fill them as per you suggestions and have the yard epoxy coat them next week before they put new boat coat on. Steve 642-2f TESA
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yorkrose |
Re: Blisters | #3 | ||
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Posts: 275 01/08/06 10:35:40 |
Steve,
If these are "real" blisters they should not dry so quickly. Since they are small and localized to a single area they may be the result of either some local flaw or from a problem during painting. Are the blisters actually under the gelcoat and into the laminate? It is usually not possible to tell if a blister is "dry" by touch alone. At the same time, it may not be possible for a standard moisture meter to read over a small area. About 10 years ago we owned a three-year-old boat (which we had purchased new) that had big (2 inch), deep, weeping blisters over many areas. Your experience in seeing blisters on a six-year-old boat is not surprising. If a boat is going to show blisters it is common to occur in the first few years. Finally, you might want to check with a blister expert in the yard before continuing your proposed plan. It is not a good idea to permanently seal a flaw with epoxy if the underlying area is wet. Regards, Gene Fuller Yorkshire Rose, C42 #870 |
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tomcharron2 |
Blisters | #4 | ||
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Posts: 50 01/08/06 19:27:46 |
Dear Steve:
Over the past 14 years I have heard a lot about blisters and have read a great deal about same. My Catalina 30 (a 1983 model) had quite a few "25 cent sized" blisters at the time of purchase in 1993. I had them properly opened, honed, repaired and filled with epoxy. Had no problem with them after repair. A few appeared from haul to haul but I repaired as they appeared. Never had any problems with the integrity of the hull. I am sure you have seen major blister repair jobs on many old and new vessels at Svends, Nelsons, Grand etc as have I....so they get opened, honed, filled, faired, and recovered all the time. My Catalina 42 (across from your slip on gate  had one blister dime sized on the starboard side forward last year at haul. I opened it honed it out, dried it and filled same with epoxy.Blisters of this size and even bigger don't worry me. (Have your ever heard of a hull failure due to blisters?...Would love to get some information on such....if it exists out there in sailing land). But from all the blisters being repaired in our local yards I have not seen nor heard hull failure, or leaks, from same. My recommendation...open them, hone them, dry them, epoxy them, rebarrier coat them, repaint the bottom.....and don't worry about these small blemishes.... Certainly I am open to other paths and welcome others comments and positions on this issue. TomCharron |
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melelana |
Re: Hull Blisters | #5 | ||
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Posts: 335 01/09/06 06:24:23 |
Steve,
As Gene points out, "dry" isn't really dry. The idea is to reduce the moisture content of the laminate, not just get the surface dry to the touch. That said, what you've descibed sounds like simple gelcoat blisters, not something that involves serious damaage to the laminate. Tom's right. Most surveyers are starting to look at blisters as a nuisance unless there's significant laminate damage. I'd look at a quick "grind and fill" as a temporary repair and make plans to carefully check the area on the next haul out. Take Gene's advice and have your yard manager take a look and give you his recommendation. Good luck, Larry |
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do335 |
Re: Hull Blisters | #6 | ||
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Posts: 257 01/09/06 19:16:59 |
Thanks everyone for the advice. I opened up the blisters and they all had water in them, but after the initial drop they appeared to be dry. I agree, I think these are minor blisters and nothing to get very excited about. Probably just typical imperfections you would see on almost any boat. They do go below the gelcoat, but I don't think any farther. I ground each one out and filled them with 3M vinylester filler. The yard will coat each with epoxy before they put the new bottom paint on. I'll keep my eye out for them on next haul out.
Steve 642-2f TESA
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jbmason |
Blisters | #7 | ||
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Posts: 246 01/09/06 21:27:29 |
The only way to totally dry out blisters is to haul out, grind out or strip, and let stand for many weeks to many months depending on the locale. I had a haul out and full gel stripping done on an Islander in Stockton, Ca. Although at one point the average temp during the day was topping 100 degrees, it was the movement of air across the hull that brought about the drying. Took about 2 an da half months to get a good moisture reading from the meter. It is a matter of time and meter readings to get drying.
Prior to that incident, I did the same procedure on a Catalina 25 by myself in the heat of Fresno, Ca. in July. Average temp 103 degrees day, 85 degrees at night. Let it dry for about two weeks, got anxious, and finished the job filling, sanding, and barrier coats, 3 coats of epoxy bottom paint. What a horrible job, but successful. I would never tackle it on a DIY. |
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