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Discussion Starter #1
I've been through the search system, and don't see this discussed in detail. I've sanded the bottom of my 35 footer, and it is my understanding that the next step is to clean it with acetone. But how is this done? Put some in a bucket and dip a wrag into it? Pour a little on a wrag? Does the wrag need to be soaked, or just damp? At the end, either way, you will end up with a bucket full of acetone with paint dust in it. How does one dispose of that mess?
 

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I'm not sure what your plan for paint is, but I stripped my 28 Oday down to gelcoat and used Interprotect 2000E followed by VC17. They recommended Fiberglass Solvent Wash 202 as a final cleaning. I don't remember where I read it but I used cheap paper towels. Lots and lots. The cheaper ones won't have printing (ink) on them. Apply a little solvent, wipe down, throw away, wipe with a fresh dry one. When done, apply clean water to the surface. If it beads up at all, you're not done. There's good info on their website.

It might have been overkill to spend the money on their solvent wash. Acetone might be just as effective, and certainly cheaper. But I figured when I'm spending that much time and money, I'm gonna follow the directions to the letter. Nothing would tick me off more than to have hauled the boat and seen the paint peeling off. And that didn't happen.
 

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Dampen rag with acetone directly from can, wipe surface of boat until acetone in rag almost dry, refold rag and apply more acetone to clean area of rag and repeat until rag dirty then use new rag. Wear gloves as it will take the natural oils from your skin.

Acetone will evaporate, so only paint or fiberglass residue in rag is a problem. Dispose of rag safely or if not too dirty I wash them and re-use.

Do not put acetone in an open container, apart from it evaporating quickly is is highly flammable.
 

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generally a

Generally a dewaxer should be used with multiple rags. About 40-50 white terry cloth rags (Sam's Club) should de-wax and clean a boat your size. The solvent softens the mold wax then the rag removes it. If you re-wipe with that rag without turning it or folding it you'll just re-apply what you took of. If your boats bottom paint had been peeling then it's a good sign the hull was never properly de-waxed and cleaned before sanding and painting. Sanding a hull that has not been properly de-waxed only makes matters worse because it drives the wax into the surface scratches even deeper..

Either Pettit Dewaxer 95 or Interlux 202 are a good choice Acetone is a great solvent but not so much for ensuring a hull has been properly de-waxed....

Photo courtesy of West marine

Photo Courtesy of Jamestown Distributors
 

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I find the thin gloves allow solvent through to easy so I would just wear the heavy rubbber gloves as i have never found any of the MSDS sheets to have much good news


And in my old and wiser age i also wear a respirator a whole lot more even when i can only smell it a bit ;)



Dont make a haz-mat mess with buckets of solvent and at least around here if you roll out old paint on paper and let it dry it is legal waste at that point

If not then we have many STOP place to allow a homeowner to dispose of things correctly
 

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It is a superb solvent.
It tends to remove paintwork a wee bit, so be careful.
A wee bit in folded rag works well, renew it regularly from a wee bottle.
I would not use a bucket as it evaporates like crazy and it is expensive
.
 

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Discussion Starter #8
Thanks, guys

I'll do a little more research on solvents other than acetone to see if any of them might work better. My boat is not down to bare fiberglass - the existing paint is in good shape, and there are only two coats on it. My plan is to clean the bottom, put on a pigmented primer coat, and then a couple of coats of ablative.
 

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Before you use acetone, wipe the bottom down with damp or wet rags. I have even used a Scotch-Brite pad.
This will remove a lot of the excess residue without having to waste acetone.
Once it has dried, then you can use the acetone.

It used to be common to hose down the bottom after sanding it. But that makes a big mess on the ground, and is usually frowned upon these days.

Good Luck!!!
 

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I'll do a little more research on solvents other than acetone to see if any of them might work better. My boat is not down to bare fiberglass - the existing paint is in good shape, and there are only two coats on it. My plan is to clean the bottom, put on a pigmented primer coat, and then a couple of coats of ablative.
I doubt that you'll need either the acetone or the primer if I read your above post correctly. If you're using the same ablative paint as is currently on the boat, I'd advise a light scuff sanding, along with repairing any damages present, and then a straight application of your bottom paint. The acetone will tend to soften the paint already on the hull and, if recommended by the manufacturer, I'd use it. If not recommended specifically, I would not as it sounds like you've a good base to adhere to.
 

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Discussion Starter #11
??????

I'm not following you, Sailaway. I sanded the bottom pretty well, and I'm down to a coat of hard paint. But there is a thin film of dust on the boat from all the sanding. If I rub my hand across the bottom it comes away the color of the paint. It would seem necessary to at least clean that stuff off of the bottom before trying to paint. I wouldn't think the paint would stick to that. You don't say anything about cleaning the bottom with any sort of liquid, which suggests painting over the remaining dust. Am I getting that right? And I thought a primer would be necessary if nothing is known about the hard paint to make sure that the ablative would stick to it.
 

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Don't use acetone. It flashes to quick and leaves sanding residue on the hull. Make sure you have a good 80 grit sand on the hull, and use either the paint company's suggested thinner, or a solvent such as Xylene. It is generic, and can be purchased anywhere. Use clean rags, and wipe in the same direction. Wipe down the hull twice. After it has dried, you are ready to apply whatever product you are going to use.
 

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Discussion Starter #13
Thanks again

I checked this morning for answers, and there weren't any new ones. The weather is 55 degrees here today - a day not to be missed in this area in February. So I went ahead - and cleaned it with MEK. It seems to have worked well; the hull feels dry and is dust free. It's epoxy repairs tomorrow, another cleaning job, and then paint time.
 
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