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Discussion Starter #1
There is about 3 or 4 layers of antifouling paint on my boat. Its thin under the water line, but thick above it. I want to take it all off. Has anyone used paint remover to get this off? Will it work? What brand? Thanks!
 

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As crazy as this sounds, a straight razor blade in the holder/gizmo's you'd use to scrape paint off a window. Scraped the majority of bottom paint off my 28' & the P.O. had the stuff caked on. It didn't take everything off but sure to make the balance of the job easier.

Someone also had mentioned using a drywall sander & screen on the end of a wooden broom pole. Easier on the back & you're not covered in dust being under the boat.
 

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Discussion Starter #3
I was hoping to roll on some citris strip, then use the pressure washer to wash the old crappy paint off. Scraping seems like a lot of elbow grease. But, hey if thats the only way. Maybe I should rent a sand blaster?
 

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Don't rent a sand blaster. That job takes an expert. Even if it didn't, you don't want to do that job, ever. Citrus strip may do nothing, you'll have to test a small spot. You can still get real aircraft stripper at autobody supply stores or any industrial paint supply.
 

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A few years ago I decided to use a soy based stripper instead of sanding/scraping. I needed to get all of the old pain off so that I could put on a barrier coat. The soy stripper would strip about one coat of old pain at a time, not the several layers advertised. So at that rate it would have been far too expensive to get down to the gelcoat. I eneded up sanding the last few layers which were very hard and well adhered to the gelcoat. One of the problems I encountered was that it turned very warm after I hauled the boat and the stripper would dry out before penetrating several layers of paint. If you have a nice overcast sky and less that 80-85 degrees I'm sure stripper will be more effective than in my experience.
Be careful with disc sanders and sharp scrapers with pointed corners as they easily gouge the gelcoat once you are through the paint. Also, they are very tedious in those complex compound curves around the rudder and keel. I would grind down the corners of any scraper I use in these areas.
Make sure the stripper you use is good for fiberglass and follow the directions carefully as many strippers have the potential to soften the gelcoat and maybe even the substrate.
Its a nasty job any way you go about it, but with stripper it is much easier to control what gets onto your skin and into your lungs.
 

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Soon there will be a new stripper on the market. You paint it on, it works through the paint and separates it cleanly from the gel coat. This is environmentally benign and uses a patented biotechnology to separate the paint from the boat. Paint comes off in your hand in big sheets when you pull on it. It was demonstrated at the Miami boat show. They did a 60 ft boat in 6 hours. The other product (I dont recall the product) used on an identical boat took 3 days to strip. Not yet on the market. Note I do have a financial interest in this product.

We also have a bottom paint that that is environmentally benign and doesnt harm the animals. This is currently in testing with the US Army Corp of Engineers for use in controlling Zebra mussels in fresh water dams.

With any luck both products will be on the market within 2 years.
 

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How big is the boat you're talking about?

I have stripped three boats, a 22, a 25, and a 35.

I stripped the 22 with an electric sander.

I stripped the 25 with a chemical stripper. Don't use the stuff you get in Lowes or Home Depot or discount stores, or house paint stores. It's much too aggressive, and will dissolve your gelcoat. Use Klean Strip paint stripper, which I believe is currently available from WM for about $29. gal. , as well as other suppliers. But, that particular variety of Klean Strip is hard to find anywhere other than a specialty store or online. The company makes different types of paint strippers. One customer evaluated it very poorly on the West site, but he wasn't using it for bottom paint. I have used it twice for antifouling, and it works, but you have to use it for the right kind of paint and you have to know how to apply it. The trick is to slather it over a large area, and then reapply it whenever it starts to dry out. Keep re-applying it, without scraping off the previous coat, until the paint softens underneath. By keeping it wet, you keep the chemical softening process going. When it's well-softened, scrape it off with a putty knife or scraper.

I stripped the 35 footer myself, and with the help of a pro. I had a professional strip all but the last 1-2 coats of old paint off the 35 footer with a power plane, and then I stripped the rest with Klean Strip. Trying to do a boat that size with chemical stripper was a bigger job than I cared to tackle.
 

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Someone also had mentioned using a drywall sander & screen on the end of a wooden broom pole. Easier on the back & you're not covered in dust being under the boat.
Please note that if you do the drywall sander/screen, you wet the surface first. Wet a few feet down with a hose and wash out the screen frequently. Actually pretty fast and it's dust free that way.
I would NEVER dry sand a bottom again. I can still remember the taste of copper, not to mention the mess downwind.
 

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If you're thinking of dry sanding antifouling paint, be aware it is a serious irratant to eyes, sinuses and skin. A dust mask won't help, you'll need a respirator, a face shield and cover every inch of skin.

The marinas use a sandblaster, wearing a full paint suit with hood and respirator.

Good luck.
 

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We stripped about 25 years of old ablative paint off our Grampian 34 a few years ago. We started with a soy-based stripper, which did soften most of the layers. It worked well, but b/c we were working outside, we had to cover it with plastic wrap for 8-10 hours while it was "cooking." This was a challenge, but fairly easily doable.

After the allotted time we pealed off the plastic to reveal a soft gunky slop which easily scrapped off. This we scrapped onto plastic sheets. What was left was a thin layer (streaks really) of bottom paint which we then sanded down with an orbital sander.

The stripper worked OK, but in the end I reverted to simply using a big paint scrapper, and then finishing with the orbital sander. The stripper probably required less elbow-grease, but in the end I'm not sure if it's any easier than scrapper and sanding.
 

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I stripped my boat 40' and did it with sheet 80 grit wet and dry keeping the anti foul wet at all times.
 

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The drywall sanding technique is intriguing and would like try it sometime. But when we stripped our boat's bottom 4 years ago, I used a 3/4" wood chisel and the paint just peeled off. No dust and not that much elbow pressure needed. Two of us did all 38' in a 10 hour day. I sande the bottom with a a shop-n-vac hooked to a 6" random orbit sander using 80 grit followed by 120 grit disks. That took 6 hours down to the gel coat all around. All together it was 26 man hours; not bad given the scope of the job and 20 layers of paint.

I would not try to sand the whole thing off and would NOT use anything except a random orbit sander in any phase. Strippers are expensive and take a lot of time to work. I saw a guy work for days getting paint off and it probably cost a fortune. But others on SailNet have done it so I'll defer to their opinion.
 

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I used the Aqua Strip product. Put it on thick, wait a couple hours depending on temp, place plastic underneath and scrape it of. Took 2 applications and still had to sand, but it works quite well to get a couple layers off. You can get it online at Home Depot by the gallon much cheaper than the marine stores.

One gallon did my Rhodes 19.
 

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I've tried chemical and mechanical methods. I prefer mechanical, ie. 80 grit discs on a variable speed angle grinder/polisher. Whatever you choose to do, cover yourself up and wear really good goggles or dust proof face mask. A full face air purifying respirator works best, especially if you decide to sand. Antifouling dust is murder on the eyes...and lungs.
 

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I used a long handle heavy scraper to take my T37 down. The scraper worked great...just a lot of muscle and determination. No easy way. and using paint removers is just adding a toxin into an already toxic procedure....
 

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Discussion Starter #17
I got the aircraft stripper. $30 at West Marine. Applied it, then tried to use a pressure washer to remove it. That did not work. The paint hardens as soon as it gets wet. So I broke down and followed the instructions. Do small areas at a time and use a scraper. It took 4 applications to get most of the paint off, since there is 4 or 5 layers. In the end, you are just smearing the paint around with the scaper. As soon as it dries, its hard paint again. Its a mess and a waste of time. Just got some 60 grit on a 5" orbital 3 amp sander, change the disks alot, got over halfway done in one day. So, I guess there is no easy way. Just sand it.....or scrape it I guess. (I hate anti-fouling paint)
 

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Discussion Starter #18
Finally got all the paint off the bottom. Ended up using a combination of suggestions. In the thick areas, I used stripper, followed by wet sanding with a dry wall screen, then finally dry sanding to the gel coat. Took two weekends. One thing to say is that it has affected my health. Skin irritations, and rash, crappy overall blahh feeling. I had eye protection, a respiratior, didnt use gloves except for when stripping. Wore shorts the first weekend, then long sleeves and jeans the second. That stuff is nasty. It seemed to have paint going back to 1979 when the boat was built. Thats before they banned the real toxic antifouling ingrediants. Just saying, cover as much of your skin as possible, especially your face or you could become the toxic avenger. The boats gunna look nice, but at what expense? I read that the TFT in older paints cause girl marine life to grow a penis. Not good, not good at all.
 

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Soon there will be a new stripper on the market. You paint it on, it works through the paint and separates it cleanly from the gel coat. This is environmentally benign and uses a patented biotechnology to separate the paint from the boat. Paint comes off in your hand in big sheets when you pull on it. It was demonstrated at the Miami boat show. They did a 60 ft boat in 6 hours. The other product (I dont recall the product) used on an identical boat took 3 days to strip. Not yet on the market. Note I do have a financial interest in this product.

We also have a bottom paint that that is environmentally benign and doesnt harm the animals. This is currently in testing with the US Army Corp of Engineers for use in controlling Zebra mussels in fresh water dams.

With any luck both products will be on the market within 2 years.

@delite
Any luck with getting this product to market?
 
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