Just bought a CD25, #609. Bottom paint is poor and had a cosmetic repair done to keel. Question: should I just clean and repaint, or should I sand off years of bottom paint and epoxy the whole bottom? There are no blisteres at all, but the surveyor found moisture readings of 10-12 (said OK for age, boat was pulled out of water same morning).
mbbradford@yahopo.com
Epoxy Bottom, or Not?
Moderator: Jim Walsh
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Ron Russell
Re: Epoxy Bottom, or Not?
Since your hull is in good shape with no blisters then applying a barrier coat shouldn't be too difficult as you haven't any repair to make.Bruce Bradford wrote: I would say the answer to that depends upon where your boat is. If you are in fresh water, part of the year, and hauled out during the winter I would probably opt for a good sanding and fresh bottom paint. Whatever paint is suited for your area. If you are in saltwater or year round I would highly recommend taking off all the old paint and applying a barrier coat system, West System and Interlux are two that come to mind. The extra work and money are worth it down the road.
Also, keeping the bottom cleaned regularly will help to extend the effectiveness of the bottom paint and may allow you more time between bottom jobs depending on your local conditions.
Ron
CD 25
Incommunicado
ronrussell@mindspring.com
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Stephen
Re: Epoxy Bottom, or Not?
The work is in getting off the bottom paint. If the paint is not too thick, and not too difficult to get off, then go ahead and re-epoxy the bottom. You will have to give the hull time to dry, then I recommend refairing it while you have the chance, and then put a barrier coat on (3M is what I used).Bruce Bradford wrote: Just bought a CD25, #609. Bottom paint is poor and had a cosmetic repair done to keel. Question: should I just clean and repaint, or should I sand off years of bottom paint and epoxy the whole bottom? There are no blisteres at all, but the surveyor found moisture readings of 10-12 (said OK for age, boat was pulled out of water same morning).
On the other hand, if I had known how much time and effort it would take to get the old bottom paint off my boat, I'm not sure I would have done it.
Do a cost/benefit analysis:
Pros include perhaps 0.5 knot faster hull speed due to refaired hull, better resistance to blisters, and chance to change bottom paints (I went with a water-based ablative which was much easier to work with and is environmentally more friendly, so I'm told).
Cons include the time the boat will be out of the water, the work and expense of the job, the fact that you may never get blisters even if you don't refinish, and the fact the hull may be clean enough so that there would be no appreciable speed advantage.
On balance, I guess I would hold off on such an expensive endeavor until I saw signs of blisters or other hull problems.
Best,
Stephen
sailing@star.net
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Stephen
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D. Stump, Hanalei
Re: Just curious?????
Stephen,
A while ago I had the emergency tiller of Hanalei (CD-30) sandblasted to remove years of rust and to make it servicable again. While talking to the sandblaster, he said that he had sandblasted the bottoms of many sailboats to remove years of paint. I don't know how he controlled the depth of blast so as not to remove fiberglas, but he seemed pretty confident. Have you ever heard of such a thing, and what do you or others think??? Thanks,
D. Stump
Hanalei
A while ago I had the emergency tiller of Hanalei (CD-30) sandblasted to remove years of rust and to make it servicable again. While talking to the sandblaster, he said that he had sandblasted the bottoms of many sailboats to remove years of paint. I don't know how he controlled the depth of blast so as not to remove fiberglas, but he seemed pretty confident. Have you ever heard of such a thing, and what do you or others think??? Thanks,
D. Stump
Hanalei
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Matt Cawthorne
Re: Just curious?????
Dave,
The marina where I keep my CD-36 uses a baking soda medium for removing bottom paint rather than sand. The jobs that I have seen them do look good. I have also seen sand blasted bottoms. The quality of the job would seem to depend heavily on the skill of the operator. I used a scraper when we did our barrier coat job. If I had it to do again I think that I would rent a dustless sander and use some heavy sandpaper to get the most of the paint off and then go back and finish the job with finer sandpaper. If you had the bottom sand blasted you might have to re-fair some areas so you would end up sanding anyway.
Matt
mcawthor@bellatlantic.net
The marina where I keep my CD-36 uses a baking soda medium for removing bottom paint rather than sand. The jobs that I have seen them do look good. I have also seen sand blasted bottoms. The quality of the job would seem to depend heavily on the skill of the operator. I used a scraper when we did our barrier coat job. If I had it to do again I think that I would rent a dustless sander and use some heavy sandpaper to get the most of the paint off and then go back and finish the job with finer sandpaper. If you had the bottom sand blasted you might have to re-fair some areas so you would end up sanding anyway.
Matt
D. Stump, Hanalei wrote: Stephen,
A while ago I had the emergency tiller of Hanalei (CD-30) sandblasted to remove years of rust and to make it servicable again. While talking to the sandblaster, he said that he had sandblasted the bottoms of many sailboats to remove years of paint. I don't know how he controlled the depth of blast so as not to remove fiberglas, but he seemed pretty confident. Have you ever heard of such a thing, and what do you or others think??? Thanks,
D. Stump
Hanalei
mcawthor@bellatlantic.net
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Stephen
Re: Just curious?????
I believe in the past there have been lengthy threads on this issue. I was strongly warned against sandblasting by the owner of the marina where I keep my boat. But some people swear by it.
I have heard again and again that the skill of the operator is paramount.
BTW, I used Peel Away, then a grinder, then a sander with rough paper, then a sander with medium-grit paper. Then I faired the bottom with the West system. Then I sanded again by hand with medium-grit paper and wiped it quickly with acetone-soaked rags to prep it for the barrier coat.
sailing@star.net
I have heard again and again that the skill of the operator is paramount.
BTW, I used Peel Away, then a grinder, then a sander with rough paper, then a sander with medium-grit paper. Then I faired the bottom with the West system. Then I sanded again by hand with medium-grit paper and wiped it quickly with acetone-soaked rags to prep it for the barrier coat.
sailing@star.net
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Brewer Ezzell
Alternate to sand blasting
In 1994, I had my Edey & Duff StoneHorse's bottom cleaned by blasting it with ceramic beads instead of sand. This worked great, did not pit like sand would have. The work had to be done in the company's shop, but that was no problem since I had a trailer for the boat.