Thru the years i have used "Kitty Hair" which consists of threads of fiberglass in a slurry and a harderner on the bottom of my boat to fill in spots where the ablative bottom paint flacks off . I do this to make as smooth a hull bottom as I can prior to repainting. This year I am looking for something better which might not fall off as readily and thought of Bondo. Is this a bad idea? Are there better products? Any help would be appreciated.
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No bondon on top of bottom paint
I do not recomend any bondo or putty on top of bottom paint. Remove the ablative with a pressure washer and put new layers on. I have stripped a bottom consisting of no less than 6 layers of bottom paint. Often I found patches of bondo hidden under the layers. You are just adding more and more weight if you don't start removing layers first. My 2 cents, Lee
I do not recomend any bondo or putty on top of bottom paint. Remove the ablative with a pressure washer and put new layers on. I have stripped a bottom consisting of no less than 6 layers of bottom paint. Often I found patches of bondo hidden under the layers. You are just adding more and more weight if you don't start removing layers first. My 2 cents, Lee
You want a ..
Vinyl Ester putty like the 3M Marine Premium Filler repair that is fine for underwater use. Regular Bondo will absorb water! See link below: Beyond the answer above filling and fairing where paint has flaked off is a bad idea! Eventually you'll want to strip the paint, perhaps barrier coat, and then re-paint starting with an ablative so you'll have less flaking. My guess is that you have a hard paint under your ablative that is near the end of it's useful life and beginning to flake and separate from the hull in certain places. I never put a hard paint on my boats, when I can avoid it, and instead start with a good quality ablative like Petit Ultima SR or Interlux Micron Extra right over a fresh bottom job. Patching areas where paint has flaked off will result in much more labor and cost when you actually strip the bottom and fair it the right way! It sounds to me like you should just leave the bottom alone and eventually strip it all the way down and do it right. As you are aware chipped hard paint can not be feathered no matter how much you try! It's time for a bottom job if you want that extra 1/10 of a knot...
Vinyl Ester putty like the 3M Marine Premium Filler repair that is fine for underwater use. Regular Bondo will absorb water! See link below: Beyond the answer above filling and fairing where paint has flaked off is a bad idea! Eventually you'll want to strip the paint, perhaps barrier coat, and then re-paint starting with an ablative so you'll have less flaking. My guess is that you have a hard paint under your ablative that is near the end of it's useful life and beginning to flake and separate from the hull in certain places. I never put a hard paint on my boats, when I can avoid it, and instead start with a good quality ablative like Petit Ultima SR or Interlux Micron Extra right over a fresh bottom job. Patching areas where paint has flaked off will result in much more labor and cost when you actually strip the bottom and fair it the right way! It sounds to me like you should just leave the bottom alone and eventually strip it all the way down and do it right. As you are aware chipped hard paint can not be feathered no matter how much you try! It's time for a bottom job if you want that extra 1/10 of a knot...
I agree with others here
that you do not want to use Bondo, or any other epoxy or vinyl putty, to fill in patches on the bottom of your boat where bottom paint has flaked off. When bottom paint flakes off a hull, it is a good idea to find out why and address that issue. I've found that when bottom paints flakes, it is mostly caused by too many layers of old paint and so it's time to chemically or mechanically get rid of those old layers of paint which do not make a good surface for new paint to adhere to. On rarer occasions, flaking could be caused by moisture in your hull, also creating a surface that new paint will not adhere to. You can usually delay the inevitable -- stripping the bottom -- only so long before you make this job harder than it has to be. You would be better served by sanding and fairing spots where paint has flaked off and filling them in with nothing more than more bottom paint -- until you bite the bullet and stip the bottom and start over again on a properly prepared surface.
that you do not want to use Bondo, or any other epoxy or vinyl putty, to fill in patches on the bottom of your boat where bottom paint has flaked off. When bottom paint flakes off a hull, it is a good idea to find out why and address that issue. I've found that when bottom paints flakes, it is mostly caused by too many layers of old paint and so it's time to chemically or mechanically get rid of those old layers of paint which do not make a good surface for new paint to adhere to. On rarer occasions, flaking could be caused by moisture in your hull, also creating a surface that new paint will not adhere to. You can usually delay the inevitable -- stripping the bottom -- only so long before you make this job harder than it has to be. You would be better served by sanding and fairing spots where paint has flaked off and filling them in with nothing more than more bottom paint -- until you bite the bullet and stip the bottom and start over again on a properly prepared surface.
Good point
Maine Sail. I did not read the entire message. I agree, strip it down to original gelcoat and start builing from that. I have done this on 3 boats now and hope to never do it again but it makes a huge difference in performance and ease of bottom maintenance in the future. I used the marine bondo as a filler in the seams of my stitch and tape dinghy I built a few years ago. I used the bondo to fill in corners so I could tape over top and have a smooth, reinforced seam. Tim R.
Maine Sail. I did not read the entire message. I agree, strip it down to original gelcoat and start builing from that. I have done this on 3 boats now and hope to never do it again but it makes a huge difference in performance and ease of bottom maintenance in the future. I used the marine bondo as a filler in the seams of my stitch and tape dinghy I built a few years ago. I used the bondo to fill in corners so I could tape over top and have a smooth, reinforced seam. Tim R.
Marine Tex...
...will do the job. It is a sort of putty - you have to mix in a small amount of liquid catalyst (provided with the kit) and on she goes. Great stuff! But, you absolutely must sand the paint off the effected area for proper adhesion.
...will do the job. It is a sort of putty - you have to mix in a small amount of liquid catalyst (provided with the kit) and on she goes. Great stuff! But, you absolutely must sand the paint off the effected area for proper adhesion.
Bondo-thank yous
I appreciate all the time everyone took to answer my question. I may opt for the 3M marine filler. Thank you.
I appreciate all the time everyone took to answer my question. I may opt for the 3M marine filler. Thank you.
Bondo OVER paint????
If the paint is that think it needs to be stripped. Sticking anything but bottom paint to bottom paint is going to lead to more problems later.
If the paint is that think it needs to be stripped. Sticking anything but bottom paint to bottom paint is going to lead to more problems later.
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