We are preparing for yet another bottom job, this time we need to remove a bunch of old paint and have some minor blister repair done. One yard advised bead blasting the hull to remove all the old paint. I have several questions. First, is there a major difference between bead blasting and sand blasting? Second, will I need to apply some type of barrier between the hull and the paint before the first coat of paint? We've had this boat for five years and this is only the third bottom job on her but there are clearly other layers of old paint under our two, she clearly needs to be cleaned up a lot before yet another layer of paint is applied. If I do need a barrier coat/primer I'd love some recommendations from others as to which type/brand to use. Does it matter on the location of the boat? Since we are in South Florida the boat is sailed year round in salt water. The paint we use, and love in this area, is ACP 60. If others in the Charlotte Harbor area have better luck with another paint please let me know.
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Many opinions forthcoming.
Bead and sand blasting are done all the time. But some will say it is too destructive, that you cannot stop before there is damage to the gelcoat. I believed that and took mine('79 H37C) down to white gelcoat by hand. Some will say that you already have all the blisters you will ever have so no need to barrier coat. I did NOT believe that and put six coats of Interlux 2000E over that nice gelcoat. I had about 50 pencil eraser size blisters that I filled first. Probably not necessary but barrier coat is relatively inexpensive compared to everything else you need to do on a twenty-three year old boat. It is very satisfying to know the hull is good "forever".
Bead and sand blasting are done all the time. But some will say it is too destructive, that you cannot stop before there is damage to the gelcoat. I believed that and took mine('79 H37C) down to white gelcoat by hand. Some will say that you already have all the blisters you will ever have so no need to barrier coat. I did NOT believe that and put six coats of Interlux 2000E over that nice gelcoat. I had about 50 pencil eraser size blisters that I filled first. Probably not necessary but barrier coat is relatively inexpensive compared to everything else you need to do on a twenty-three year old boat. It is very satisfying to know the hull is good "forever".
Even the experts will tell you...
...that abrasive blasting does even limited damage in the most skilled hands. There are, however, cases where abrasive blasting is necessary. There is no escape from the long and arduous task of stripping and sanding. As far as I'm concerned, the most valuable tool for this job is the checkbook. I am a veteran of many hours of glass work and surface finishing (both marine and auto) and tend to agree with Ed. There are no shortcuts, no miracle preparations, nor a magic wand. Just clear-cut step-by-step processes to properly repair and finish a surface, ANY surface. Shortcuts and omissions will only lead to more work later on. Bottom line...The finished product is only as good as the preparation work. Cheers, Bob
...that abrasive blasting does even limited damage in the most skilled hands. There are, however, cases where abrasive blasting is necessary. There is no escape from the long and arduous task of stripping and sanding. As far as I'm concerned, the most valuable tool for this job is the checkbook. I am a veteran of many hours of glass work and surface finishing (both marine and auto) and tend to agree with Ed. There are no shortcuts, no miracle preparations, nor a magic wand. Just clear-cut step-by-step processes to properly repair and finish a surface, ANY surface. Shortcuts and omissions will only lead to more work later on. Bottom line...The finished product is only as good as the preparation work. Cheers, Bob
Check on Soda blasting or stripping
Steven: Check out soda blasting. It is suppose to be less destructive. There is also the stripping methods where you use a chemical stripper and cover with paper. Leave this on for several hour and most of the paint should be gone. This still leave quite a bit of work but at least you will still have gelcoat when you are done. I have to agree with Ed. Use a barrier coat before you new bottom job. Check out the interlux site. They have some good info on redoing the bottom.
Steven: Check out soda blasting. It is suppose to be less destructive. There is also the stripping methods where you use a chemical stripper and cover with paper. Leave this on for several hour and most of the paint should be gone. This still leave quite a bit of work but at least you will still have gelcoat when you are done. I have to agree with Ed. Use a barrier coat before you new bottom job. Check out the interlux site. They have some good info on redoing the bottom.
Makers of West System have a video
On the various methods of stripping off old aint and gelcoat. I found it a mine of information. They specifically deal with blasting etc. If you go the the gelcoat and plastics forum and then go to Fiberglass Trilogy 3 you will see a ref to this video (I think with phone number). Good luck- I am putting off doing my boat until I get a little more money and time but it does have a good barrier coat! Jim W
On the various methods of stripping off old aint and gelcoat. I found it a mine of information. They specifically deal with blasting etc. If you go the the gelcoat and plastics forum and then go to Fiberglass Trilogy 3 you will see a ref to this video (I think with phone number). Good luck- I am putting off doing my boat until I get a little more money and time but it does have a good barrier coat! Jim W
Power washer worked for me!
I, too, had about 10 yrs worth of paint on my hull. In fact, for the last 3 years, all I did was paint the spots where paint chipped off. Looked like hell but I was able to let the paint (ablative) wear off a bit. Finally, I bit the bullet and borrowed a friend's 2200 psi pressure washer. With a 15 degree nozzle, and keeping the tip about 3-4 inches from the hull, I was able, in narrow strips about 3 inches wide, remove 98% of the paint. I then sanded the hull with an orbital sander with 80-grid paper to get off the spots I missed. I then washed it down well, and applied a coat of ablative paint. It came out beautifuly! Time involved: 6 hours to pressure wash, about 8 hours to sand (slow going but it sure built my arms up!).
I, too, had about 10 yrs worth of paint on my hull. In fact, for the last 3 years, all I did was paint the spots where paint chipped off. Looked like hell but I was able to let the paint (ablative) wear off a bit. Finally, I bit the bullet and borrowed a friend's 2200 psi pressure washer. With a 15 degree nozzle, and keeping the tip about 3-4 inches from the hull, I was able, in narrow strips about 3 inches wide, remove 98% of the paint. I then sanded the hull with an orbital sander with 80-grid paper to get off the spots I missed. I then washed it down well, and applied a coat of ablative paint. It came out beautifuly! Time involved: 6 hours to pressure wash, about 8 hours to sand (slow going but it sure built my arms up!).
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