When I hauled out last Fall I noticed several areas below the waterline that have small "pimples". I have applied one coat of VC17 every year on my 1988 C30 and have always sailed it on Lake Erie. I suspect this is blistering, but am not completely sure. Anyone know if this is the case and how to fix this? Also, I am wondering if this should be repaired before another season in the water? Thanks for your help.
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Bob
Tons of Information
"Pimples", imply to me that you probably have a blister problem; however, that cannot be confirmed without hauling the vessel out for a thorough inspection whereby you have to pressure wash the bottom for a good look. You did not elaborate Bill on the quantity and how big some may be. Osmotic blistering is more common in fresh water then salt due to the differences in density coupled with temperature. Their is a plethera of information on the subject, but depending on the number and locations, you should attend to them at your earliest convenience. When I hauled my 1984 Hunter 25 several years ago before I bought my 1988 Catalina 30, I counted over 800 blisters ranging from small nail head size to a half-dollar. I read up on the subject, bought a grinder and proceeded to go to work, successfully repairing the damage, painting the bottom and selling the boat. It was not a fun experience, but hanging out in the do-it-yourself yard and witnessing others repairing the same, the information sharing added to the success of the repairs. I think blisters though are often overrated. Their are many who are of that school that feel the damage never gets that extensive as to sink a vessel by a complete break-thru. Its only when the blisters beocme so abundant and form an extensive mat type pattern where gelcoat peeling is required, which can be very expensive and time consuming. I understand that barrier coats as well are not absolute insurance for blister prevention. When I hauled my 30 last July I repaired seven small blisters and applied three coats of ablative paint. I feel the secret to prevention on blisters is to inspect and repaint every two - three years or as necessary as long as the boat remains in fresh water. If your handy, the physical repair of a blister itself is quite simple. The most difficult part I thought was the application of the fiberglass filler as once its cure's its a tough one to sand and fair. Regards Bob
"Pimples", imply to me that you probably have a blister problem; however, that cannot be confirmed without hauling the vessel out for a thorough inspection whereby you have to pressure wash the bottom for a good look. You did not elaborate Bill on the quantity and how big some may be. Osmotic blistering is more common in fresh water then salt due to the differences in density coupled with temperature. Their is a plethera of information on the subject, but depending on the number and locations, you should attend to them at your earliest convenience. When I hauled my 1984 Hunter 25 several years ago before I bought my 1988 Catalina 30, I counted over 800 blisters ranging from small nail head size to a half-dollar. I read up on the subject, bought a grinder and proceeded to go to work, successfully repairing the damage, painting the bottom and selling the boat. It was not a fun experience, but hanging out in the do-it-yourself yard and witnessing others repairing the same, the information sharing added to the success of the repairs. I think blisters though are often overrated. Their are many who are of that school that feel the damage never gets that extensive as to sink a vessel by a complete break-thru. Its only when the blisters beocme so abundant and form an extensive mat type pattern where gelcoat peeling is required, which can be very expensive and time consuming. I understand that barrier coats as well are not absolute insurance for blister prevention. When I hauled my 30 last July I repaired seven small blisters and applied three coats of ablative paint. I feel the secret to prevention on blisters is to inspect and repaint every two - three years or as necessary as long as the boat remains in fresh water. If your handy, the physical repair of a blister itself is quite simple. The most difficult part I thought was the application of the fiberglass filler as once its cure's its a tough one to sand and fair. Regards Bob
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Paul
Repair Early
Bill, There have been a number of posts on this site on this subject. If you do a search you should find them. My take -- strip all paint from the bottom and sand with 80 grit. The sanding should open most blisters to drain. Best to do this now and let the boat stand and dry till spring. If these are small blisters it could be that you can just put on barrier coat with no repairs. If serious it may be necessary to let dry all summer before doing anything more. I have used successfully used Interlux 2000/2001 on three boats. The boat must be dry before using this product. Best of luck, P
Bill, There have been a number of posts on this site on this subject. If you do a search you should find them. My take -- strip all paint from the bottom and sand with 80 grit. The sanding should open most blisters to drain. Best to do this now and let the boat stand and dry till spring. If these are small blisters it could be that you can just put on barrier coat with no repairs. If serious it may be necessary to let dry all summer before doing anything more. I have used successfully used Interlux 2000/2001 on three boats. The boat must be dry before using this product. Best of luck, P
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Bill Wehmer
Some More Information
Thanks for the replies. The pimples are very small...like pinhead size...and very numerous. It almost looks like dirt was in the paint. When the last coat was applied in April 2004 the condition did not exist. Does this information make any difference in your suggestions? Thanks again.
Thanks for the replies. The pimples are very small...like pinhead size...and very numerous. It almost looks like dirt was in the paint. When the last coat was applied in April 2004 the condition did not exist. Does this information make any difference in your suggestions? Thanks again.
Small is better
Bill, You will have to be the judge. What I would try is to strip the paint, sand with 80 grit to open all the blisters (pimples) open and drained. Let the boat dry out and get someone to put a moisture meter on it around May 1st. If it is dry get the 2000/2001 and follow the directions. After the last coat of barrier coat goes on and before it is completely dry, put on your first coat of bottom paint. Use a very short roller, I like mohair -- they are the best for bottom paint. Good for the barrier coat too. Best of luck and let me know how this turns out. You can contact me at ilove2sail@intercom.net Paul
Bill, You will have to be the judge. What I would try is to strip the paint, sand with 80 grit to open all the blisters (pimples) open and drained. Let the boat dry out and get someone to put a moisture meter on it around May 1st. If it is dry get the 2000/2001 and follow the directions. After the last coat of barrier coat goes on and before it is completely dry, put on your first coat of bottom paint. Use a very short roller, I like mohair -- they are the best for bottom paint. Good for the barrier coat too. Best of luck and let me know how this turns out. You can contact me at ilove2sail@intercom.net Paul
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Gerry, GMJ Marine
Pimples
Bill, these pinhead blisters are nothing to be worried too much about right now. In a lot of instances these are not caused by water but by small amounts of saturated,uncured trapped resin in the layup of the first layers of glass. As you said they weren't there in 2004 so whatever the reason for them it is just beginning to manifest itself now. If your bottom paint isn't screaming to be stripped off, then a better approach would be to map out your bottom on paper with the location of these areas of blisters. Mark out the areas on the paper with say a circle or square and write in the measurements that the areas cover. Sail the summer away and when you haul next fall check the bottom as soon as the pressure washing is dry. Compare it to the map you made to see if the problem is increasing or is static. Sometimes these blisters get a pressure pinhole in the dome and if they sit for a while drying out they deflate and then are hard to find. This also happens when you sand the surface with sand paper so you should plan to mark out the perimeter of the affected area with a marker about 6 inches outside the field so you don't sand the marking away. Barrier coating does not fix blisters, they have to be filled if they're small or ground or peeled in severe cases then glassed back to a fair surface. When the repair is completed then you apply the barrier coat. I prefer Inter-Lux Interprotect 2001E Grey. In any case I wouldn't lose too much sleep over this for a couple of seasons until you follow up with your map and see what is actually happening. Good luck Bill.
Bill, these pinhead blisters are nothing to be worried too much about right now. In a lot of instances these are not caused by water but by small amounts of saturated,uncured trapped resin in the layup of the first layers of glass. As you said they weren't there in 2004 so whatever the reason for them it is just beginning to manifest itself now. If your bottom paint isn't screaming to be stripped off, then a better approach would be to map out your bottom on paper with the location of these areas of blisters. Mark out the areas on the paper with say a circle or square and write in the measurements that the areas cover. Sail the summer away and when you haul next fall check the bottom as soon as the pressure washing is dry. Compare it to the map you made to see if the problem is increasing or is static. Sometimes these blisters get a pressure pinhole in the dome and if they sit for a while drying out they deflate and then are hard to find. This also happens when you sand the surface with sand paper so you should plan to mark out the perimeter of the affected area with a marker about 6 inches outside the field so you don't sand the marking away. Barrier coating does not fix blisters, they have to be filled if they're small or ground or peeled in severe cases then glassed back to a fair surface. When the repair is completed then you apply the barrier coat. I prefer Inter-Lux Interprotect 2001E Grey. In any case I wouldn't lose too much sleep over this for a couple of seasons until you follow up with your map and see what is actually happening. Good luck Bill.
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Randy Kolb
Pimple Mapping
I have some pimple sized blisters on my hull too. They've been there since I bought the boat 5 years ago. This year I decided to do an experiment. I marked a place on the hull (measured distance from the transom) where there were a fair amount of pimples and took a piece of waxed paper and taped it to the hull (about 3 square feet)there. Then I used a felt tip marker to note on the wax paper each pimple by outlining the pimple. Next year when I haul out I will put the wax paper back on and see if anything has changed. If the situation is getting worse then I'll do something about it. If it is static then I'll relax.
I have some pimple sized blisters on my hull too. They've been there since I bought the boat 5 years ago. This year I decided to do an experiment. I marked a place on the hull (measured distance from the transom) where there were a fair amount of pimples and took a piece of waxed paper and taped it to the hull (about 3 square feet)there. Then I used a felt tip marker to note on the wax paper each pimple by outlining the pimple. Next year when I haul out I will put the wax paper back on and see if anything has changed. If the situation is getting worse then I'll do something about it. If it is static then I'll relax.
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