OK folks, I've read 20 dozen articles on blister repair but I'm at a loss now. A couple weeks ago I started grinding out the blisters in the hull of our 1977 Hunter 27. After doing about 200 of them -- from dime size to dollar size (paper dollar!) I gave that up and bought a planer. I spent yesterday and today planing all of the old paint and gel coat off the hull, from about 6 inches above the waterline to the bottom. This boat doesn't just have individual blisters, it has whole patches of them... great swaths of rot. Some sections of the hull look something like really bad, week-old poison ivy rashes -- you know, the kind that ooze pus and then dry out? That's the kind of texture I'm looking at. OK, I can deal with grinding out a couple hundred blisters and letting it all dry out for a couple of months, then sealing, filling, fairing, painting, etc. But what am I supposed to do with these big patches of blisters? I'm talking about patches that are approximately 2'x3' in size. What's most distressing is that it isn't just under the gel coat -- they are all at least one, sometimes two layers deep into the fiberglass. I'd attack the stuff with the planer, but I'm really concerned that I'm going to have to go so deep that I literally won't have any hull left. Has anyone here had to deal with this before? What did you do? Or is it simply time to cut the boat up for scrap?
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Test your hull thickness.
Doug: You may need to test your hull thickness. I think you will find that it may be thicker than you think. While these blisters/spots are drying out be sure to flush them out with fresh water. One of the treatments for these problems is bondo. If you go back into the archives and search for Blisters
Doug: You may need to test your hull thickness. I think you will find that it may be thicker than you think. While these blisters/spots are drying out be sure to flush them out with fresh water. One of the treatments for these problems is bondo. If you go back into the archives and search for Blisters
D
Doug T.
Steve
Thanks, Steve -- I've read them all (I think you posted a long list of links a couple months ago...) I'm familiar with the procedures -- I'm just aghast at the extent of the problem on this boat. I'll try to post some pictures, but I'm sure the pictures won't really show how bad it is in person. I've heard that serious blistering could cause structural problems, but I hadn't seen it with my own eyes before: there's a section of hull on the starboard side near the bow that I'd be reeeeeeally afraid to hit a bouy with. Sigh. Well, this'll be a really good fiberglass lay-up training course if nothing else... I'm going to have the resident pro at our marina take a look at it this week and give me a recommendation. I'm giving 50-50 odds he'll recommend that we give up, paint over it, and wear PFDs at all times when on the water.
Thanks, Steve -- I've read them all (I think you posted a long list of links a couple months ago...) I'm familiar with the procedures -- I'm just aghast at the extent of the problem on this boat. I'll try to post some pictures, but I'm sure the pictures won't really show how bad it is in person. I've heard that serious blistering could cause structural problems, but I hadn't seen it with my own eyes before: there's a section of hull on the starboard side near the bow that I'd be reeeeeeally afraid to hit a bouy with. Sigh. Well, this'll be a really good fiberglass lay-up training course if nothing else... I'm going to have the resident pro at our marina take a look at it this week and give me a recommendation. I'm giving 50-50 odds he'll recommend that we give up, paint over it, and wear PFDs at all times when on the water.
Not that uncommon!
Doug: I do not think that your problem is that uncommon. I have heard of many people having to peel the bottom of their entire boat to get rid of the pox/blisters. The underwater portion of these boat are extremely thick. Hope yours just turn out to be a "NO BIG DEAL". Good Luck.
Doug: I do not think that your problem is that uncommon. I have heard of many people having to peel the bottom of their entire boat to get rid of the pox/blisters. The underwater portion of these boat are extremely thick. Hope yours just turn out to be a "NO BIG DEAL". Good Luck.
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Rick Belew
West Systems
Get a book from West Systems I think its free or at least inexpensive but anyway it goes over all type of problems plus they have a video with for non-readers. It covers most type of blisters and what they recommend. Good luck.
Get a book from West Systems I think its free or at least inexpensive but anyway it goes over all type of problems plus they have a video with for non-readers. It covers most type of blisters and what they recommend. Good luck.
P
Peter Albright
One more link
Steve may have had this, but it's my favorite. There is a guy who will bring in industrial dehumidification equipment to dry you out quickly. I think just the electric bill will kill you. If you have a cold, dry winter coming, tent it, heat it, and wash it down a lot. By spring it should be dried out. Use epoxy, and vacuum bag it. Replace what you've removed. Pick your favorite barrier coat and your done. Make sure you keep the bilge dry, so it won't get wet from the inside out. Remember, it has taken 24 years to get this bad. Pete Albright s/v Nancy Ross, 1977 H30 ps: mine were small, and not too many. I'm not looking past what the surveyor found two years ago.
Steve may have had this, but it's my favorite. There is a guy who will bring in industrial dehumidification equipment to dry you out quickly. I think just the electric bill will kill you. If you have a cold, dry winter coming, tent it, heat it, and wash it down a lot. By spring it should be dried out. Use epoxy, and vacuum bag it. Replace what you've removed. Pick your favorite barrier coat and your done. Make sure you keep the bilge dry, so it won't get wet from the inside out. Remember, it has taken 24 years to get this bad. Pete Albright s/v Nancy Ross, 1977 H30 ps: mine were small, and not too many. I'm not looking past what the surveyor found two years ago.
J
Jim WIllis
Blister Blast
There is lots of stuff on the internet (Steve Dion has the biggest list). I researched this and have just made a sort of "child's guide to blisters". It is based both upon my own (limited ) experience, those of several friends (I have observed their work), also results of a "round robin" hunt for people's experiences here on the forum and in Phil's posting a few months ago. I found the best source of material (but of course also a sales pitch) in the video from Gougeon Brothers Inc. 1-989 684 7286.They also have the same/similar thing in booklet form. Now to my "two penneth" of advice. 1. You can test for thickness in a few places. with a very thin drill so as not to do much harm and easily plug it with epoxy. Actually I kept core samples from my boat from areas whre I had items like extra through hulls inserted. 2. In the worst area, grind out a shallow "dish" are are just wide enough to see the various layers and until you reach clear (not milky) hard resin (prod with a sharp ppointed awl as you grind in to test for hardness). This will give you the real extend of the problem since you have to remove all the soft/milky stuff. 3. If this shows (after the drill trick) that the grinding is going in danergously deep, you obviously cannot take off ALL the damaged old laminate at once since the boat would lose structural integrity. Instead you could just fix these worse areas (with epoxy and glass reinforcement)one or two at a time, so that the boat structural integrity is maintained as you move to the next worse area and so on. 4. Finally plane down a thin amount over the rest of the hull (removing as little as possible) and cover with new laminate. Use Epoxy rather than polyester because it is more water resistant. 5. According to Gougeon, you can also use careful abrasive blasting but you have to be very careful. 6. Finally Do the whole thing with layers of Epoxy (of vinyl ester) fairing, barrier coat etc (as in the video). 7. I almost forgot DRYING!. THis is the most important part. A dry bilge, and well-aired boat helps dry from the insdie. Eventually finish with Epoxy barrier coat and (I highly recommend as on my boat) a leak-proof prop-shaft seal. 8. The outer hull has to be absolutely dry before all the laminating work ahead of you. I hope that you are not charged for "lay days".Rinse the old blister fluid away with steam or hot water if possible so that you are not making the area unecessarily wet again!. Try to get a moisture meter and use it to record the drying process! These are just the procedures that I would do with my boat- no guarantees! However, if you care to e-mail me through www.islandgirlproducts.com I will send you our Nov Newsletter that has most of this in it. Phil will be posting the blister stuff on this forum as Part III of the "Fiberglass Trilogy" Best of Luck Jim Willis
There is lots of stuff on the internet (Steve Dion has the biggest list). I researched this and have just made a sort of "child's guide to blisters". It is based both upon my own (limited ) experience, those of several friends (I have observed their work), also results of a "round robin" hunt for people's experiences here on the forum and in Phil's posting a few months ago. I found the best source of material (but of course also a sales pitch) in the video from Gougeon Brothers Inc. 1-989 684 7286.They also have the same/similar thing in booklet form. Now to my "two penneth" of advice. 1. You can test for thickness in a few places. with a very thin drill so as not to do much harm and easily plug it with epoxy. Actually I kept core samples from my boat from areas whre I had items like extra through hulls inserted. 2. In the worst area, grind out a shallow "dish" are are just wide enough to see the various layers and until you reach clear (not milky) hard resin (prod with a sharp ppointed awl as you grind in to test for hardness). This will give you the real extend of the problem since you have to remove all the soft/milky stuff. 3. If this shows (after the drill trick) that the grinding is going in danergously deep, you obviously cannot take off ALL the damaged old laminate at once since the boat would lose structural integrity. Instead you could just fix these worse areas (with epoxy and glass reinforcement)one or two at a time, so that the boat structural integrity is maintained as you move to the next worse area and so on. 4. Finally plane down a thin amount over the rest of the hull (removing as little as possible) and cover with new laminate. Use Epoxy rather than polyester because it is more water resistant. 5. According to Gougeon, you can also use careful abrasive blasting but you have to be very careful. 6. Finally Do the whole thing with layers of Epoxy (of vinyl ester) fairing, barrier coat etc (as in the video). 7. I almost forgot DRYING!. THis is the most important part. A dry bilge, and well-aired boat helps dry from the insdie. Eventually finish with Epoxy barrier coat and (I highly recommend as on my boat) a leak-proof prop-shaft seal. 8. The outer hull has to be absolutely dry before all the laminating work ahead of you. I hope that you are not charged for "lay days".Rinse the old blister fluid away with steam or hot water if possible so that you are not making the area unecessarily wet again!. Try to get a moisture meter and use it to record the drying process! These are just the procedures that I would do with my boat- no guarantees! However, if you care to e-mail me through www.islandgirlproducts.com I will send you our Nov Newsletter that has most of this in it. Phil will be posting the blister stuff on this forum as Part III of the "Fiberglass Trilogy" Best of Luck Jim Willis
E
Ed Schenck
Hull thickness.
Steve wrote that it "may be thicker than you think". It may also be thinner than you think. My 1979 H37C is very solid. But when I passed around a core sample at a marina luncheon everyone said "why so thin?". I had drilled for a thru-hull right in the center of the bootstripe. That area is about 5/16". My guess is there should be nothing around the waterline under 1/4". Two feet from the waterline you can expect at least 3/8". All guesses. Good luck.
Steve wrote that it "may be thicker than you think". It may also be thinner than you think. My 1979 H37C is very solid. But when I passed around a core sample at a marina luncheon everyone said "why so thin?". I had drilled for a thru-hull right in the center of the bootstripe. That area is about 5/16". My guess is there should be nothing around the waterline under 1/4". Two feet from the waterline you can expect at least 3/8". All guesses. Good luck.
D
Doug T.
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Ed Schenck
Strange thing, blisters.
The Morgan next to me has lots of small blisters. But they are all in the bootstripe or higher! Go figure. Doug, you should find around 3/4" at the thru-hulls. Don't figure on that thickness going very far up the sides however.
The Morgan next to me has lots of small blisters. But they are all in the bootstripe or higher! Go figure. Doug, you should find around 3/4" at the thru-hulls. Don't figure on that thickness going very far up the sides however.
J
Jim WIllis
Blisters in the boot stripe
THe only real blisters I had (about 3 years ago) were also in the boot stripe!. This is because the boat leaned over and set lower than originally intended. Whoever suggested bringing the barrier coat up under the stripe was right on! Isn't it more fun talking about all this than getting dirty and unhealthy under the boat! Jim W
THe only real blisters I had (about 3 years ago) were also in the boot stripe!. This is because the boat leaned over and set lower than originally intended. Whoever suggested bringing the barrier coat up under the stripe was right on! Isn't it more fun talking about all this than getting dirty and unhealthy under the boat! Jim W
D
Doug T.
High up blisters
A possible contributing factor to the zillions of pin head blisters above the waterline was the fact that some time in the past, the boat took on about 8-10" of water. I have no idea how long it sat in that condition, but there's a distinct waterline on the v-berth door, and as I clean up hard-to-get-at areas, I keep finding old deposits of mud and other debris. For all I know, it sat like that for a year or more... no way to find out now. These little blisters were NOT deep, though -- just in the gel coat. The planer took them off very easily.
A possible contributing factor to the zillions of pin head blisters above the waterline was the fact that some time in the past, the boat took on about 8-10" of water. I have no idea how long it sat in that condition, but there's a distinct waterline on the v-berth door, and as I clean up hard-to-get-at areas, I keep finding old deposits of mud and other debris. For all I know, it sat like that for a year or more... no way to find out now. These little blisters were NOT deep, though -- just in the gel coat. The planer took them off very easily.
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