I plan to have the local yard paint the bottom of my 1981 Catalina 30 next week. They will haul the boat on friday morning so that I can work on it over the weekend. On Monday they will start to paint. Now the questions... 1. Can I get a recomendation on a book that details blister repair? 2. Is a weekend enough time to do any blister repair? Is there a long cure time? 3. can anyone outline the basic proceedure for minor gel coat blister repair? 4. What equipment and materials will I need? Thanks for the help.
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To do it Correctly, Plan on a Month(not a weekend)
It depends a lot on the size and quanity of blister. - Strip all the bottom paint (easier said than done). Be sure to use dust protection, more than a paper mask is required. - Open blisters up one by one with e Dremel grinding tool - wash the bottom then let it dry out for a month or more - fill blister holes with epoxy, sand after hardening - apply a good barrier coat, 4-5 coats usually required - apply bottom paint I can be done faster but it's not a weekend job. Usually costs $100/foot or more to do it correctly. "You can have it right or have it right away."
It depends a lot on the size and quanity of blister. - Strip all the bottom paint (easier said than done). Be sure to use dust protection, more than a paper mask is required. - Open blisters up one by one with e Dremel grinding tool - wash the bottom then let it dry out for a month or more - fill blister holes with epoxy, sand after hardening - apply a good barrier coat, 4-5 coats usually required - apply bottom paint I can be done faster but it's not a weekend job. Usually costs $100/foot or more to do it correctly. "You can have it right or have it right away."
Books and websites.
I did some minor blister repair using the West System booklet as a guide(http://www.westsystem.com/). It is available in most chandleries. Some websites: http://www.sailnet.com/ - "Gear and Maintenance". http://catalog.com/bobpone/ - Marine DIY, lots of tips. http://www.mooremarine.com/index.htm - excellent blister article in "Tech Corner". I had several pencil eraser size blisters(1979 H37C). Touched them with a Dremmel and filled with the West System mix. Took very little sanding before the barrier coat.
I did some minor blister repair using the West System booklet as a guide(http://www.westsystem.com/). It is available in most chandleries. Some websites: http://www.sailnet.com/ - "Gear and Maintenance". http://catalog.com/bobpone/ - Marine DIY, lots of tips. http://www.mooremarine.com/index.htm - excellent blister article in "Tech Corner". I had several pencil eraser size blisters(1979 H37C). Touched them with a Dremmel and filled with the West System mix. Took very little sanding before the barrier coat.
Under pressure
Steve, Ed and homer have you covered. When you pop those blisters. watch your eyes, they POP little pieces of gelcoat . r.w.landau
Steve, Ed and homer have you covered. When you pop those blisters. watch your eyes, they POP little pieces of gelcoat . r.w.landau
Steve check this out.
http://www.osmosisinfo.com/index2.html This should give you the info that you need.
http://www.osmosisinfo.com/index2.html This should give you the info that you need.
THE GREAT LEARNING CURVE!!
Osmosisinfo.com had the deepest explanation of the gelcaot/water problem I have seen, although there is some "off the wall" stuff about leaving bllisters open if there is no time to wash them out and dry them.' They basically said that if the resin ahd been heat cured there never would be a problem, but uncured resin, "wick effect of "fibers etc are all contributing factors. The stuff on Sailnet.com was more readable and reiterated some fo the same facts. Interestingly blisters per se are not the problem its the soggy/cloudiness of the underlying fiberglass resin as it gets water penetrated. Older hulls did not get blisters but could still get water-damaged. All of this is, of course, the worst case scenariao, Blisters between gelcoat and fiberglass lay up only are more trivial but the resin underneath should look clear (the big guys who charge $500 per foot for redoing laminates make an inspection window with a grinder to measure depth of water penetration. One thing I learned is that all blisters should be well washed out with fresh water before drying and fixing. Otherwise the trapped acids cause a return of the problem. Of course, living in the world of reality with $25 to $45 per day lay day charges real drying is almost impossible wihtout special measures. Blisters in in paint (even barrier coat) are also likely. I even remember painting a car with acrylic lacquer, wet sanding it proior to top-coating and it then rained almost daily for 2 months. It got little osmotic blisters with water in them!. I'll try to summarize all this and more in FIberglass Trilogy III coming out in May 2001. Jim W
Osmosisinfo.com had the deepest explanation of the gelcaot/water problem I have seen, although there is some "off the wall" stuff about leaving bllisters open if there is no time to wash them out and dry them.' They basically said that if the resin ahd been heat cured there never would be a problem, but uncured resin, "wick effect of "fibers etc are all contributing factors. The stuff on Sailnet.com was more readable and reiterated some fo the same facts. Interestingly blisters per se are not the problem its the soggy/cloudiness of the underlying fiberglass resin as it gets water penetrated. Older hulls did not get blisters but could still get water-damaged. All of this is, of course, the worst case scenariao, Blisters between gelcoat and fiberglass lay up only are more trivial but the resin underneath should look clear (the big guys who charge $500 per foot for redoing laminates make an inspection window with a grinder to measure depth of water penetration. One thing I learned is that all blisters should be well washed out with fresh water before drying and fixing. Otherwise the trapped acids cause a return of the problem. Of course, living in the world of reality with $25 to $45 per day lay day charges real drying is almost impossible wihtout special measures. Blisters in in paint (even barrier coat) are also likely. I even remember painting a car with acrylic lacquer, wet sanding it proior to top-coating and it then rained almost daily for 2 months. It got little osmotic blisters with water in them!. I'll try to summarize all this and more in FIberglass Trilogy III coming out in May 2001. Jim W
years later
my shoulders ache just thinkin' about repairing blisters. the thought of useing a dremel tool to open up blisters i think would be a increadibly slow process! i suggest you rent a makita 4'' disc. sander, i have seen where you can open up a blister and its diameter at the base is much larger than what you see at the surface! you must feather them out and if you watch closely while grining you can 'read' the glass ie: theres a slight white edge (watch closely for it) where the blisters delam was continuing along untill the grinder found it. this works well if there are not many blisters but if theres alot then a complete shaving job is required west systems great to work with and petit makes a great 2 part epoxy fairing compound thats easy to work with (700/7025 i think) both are fairly easy to sand (theres that ache again!) and then its on to fun with barrier coating (and my wife always bugs me about my paint prep when doing interior painting!!) i'm thinking at the short end it;s a two week job to do it properly and that's using infared heat to speed the drying out process. have fun!
my shoulders ache just thinkin' about repairing blisters. the thought of useing a dremel tool to open up blisters i think would be a increadibly slow process! i suggest you rent a makita 4'' disc. sander, i have seen where you can open up a blister and its diameter at the base is much larger than what you see at the surface! you must feather them out and if you watch closely while grining you can 'read' the glass ie: theres a slight white edge (watch closely for it) where the blisters delam was continuing along untill the grinder found it. this works well if there are not many blisters but if theres alot then a complete shaving job is required west systems great to work with and petit makes a great 2 part epoxy fairing compound thats easy to work with (700/7025 i think) both are fairly easy to sand (theres that ache again!) and then its on to fun with barrier coating (and my wife always bugs me about my paint prep when doing interior painting!!) i'm thinking at the short end it;s a two week job to do it properly and that's using infared heat to speed the drying out process. have fun!
Blisters
One season I sanded the rudder and skeg aggressively. When the boat came out of the water I found 135 blisters on the skeg and rudder. I ground them out with a drill fitted with a grinding stone appropiately shaped. Cleaned them out, washed with fresh water and let them sit all through the winter layup to dry out. Then filled with Interlux epoxy putty, sanded, sealed, barrier coated and painted. Never got another blister. I used the Interlux system. They now recommend using a sealer on the ground out "holes" after they dry out but before filling. I think their new sealer if TriLux(?) According to their representative, this is to prevent the patch plug from popping out. I have not had this problem. A weekend is not enough time. If you are committed to your launch date consider making repairs at haul out. Good Luck, Pat
One season I sanded the rudder and skeg aggressively. When the boat came out of the water I found 135 blisters on the skeg and rudder. I ground them out with a drill fitted with a grinding stone appropiately shaped. Cleaned them out, washed with fresh water and let them sit all through the winter layup to dry out. Then filled with Interlux epoxy putty, sanded, sealed, barrier coated and painted. Never got another blister. I used the Interlux system. They now recommend using a sealer on the ground out "holes" after they dry out but before filling. I think their new sealer if TriLux(?) According to their representative, this is to prevent the patch plug from popping out. I have not had this problem. A weekend is not enough time. If you are committed to your launch date consider making repairs at haul out. Good Luck, Pat
I am there!
I had the same problem, The boat has been shaved last october (complete shave, under water line) It dried for the winter. Now it's time to patch and Interprotect. It's a long job, but if you do it well, you will never have to do it again. I suggest a small book by Interlux (free) that explain blisters, and the way to cure them. Good luck.. Lambert. (sorry for my english)
I had the same problem, The boat has been shaved last october (complete shave, under water line) It dried for the winter. Now it's time to patch and Interprotect. It's a long job, but if you do it well, you will never have to do it again. I suggest a small book by Interlux (free) that explain blisters, and the way to cure them. Good luck.. Lambert. (sorry for my english)
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