How to - Remove Anti-Fouling Paint

[Bubba1235]

Picked up a new project and even though its a 100% fresh water boat the previous owner used anti-fouling paint on the hull. Can you say mud fence ugly?

Sooo... are there strippers that will remove this gunk or is it down to old fashioned sanding? Some one please tell me there is a better way!

 

[gcboat]

Re: How to - Remove Anti-Fouling Paint

Hey Bubba -
First off be really careful using a commercial grade stripper. Many are not fiberglass safe. You'll end up doing more harm than good. Here's one product that is fiberglass / gelcoat safe :http://www.nauticexpo.com/prod/international/anti-fouling-stripper-21586-50905.html
Ane here's another:http://www.dumondchemicals.com/html/peelaway.htm

None are inexpensive - if it says marine you just know the price will be a premium.

 

[AquaTom]

Re: How to - Remove Anti-Fouling Paint

Sandblasting does a good quick job but messy,you have to contain the blast media and bottom paint.What I usually do is scrape off any loose paint first,then sand or use a stripper.Are you going to repaint or try to bring the hull back to gelcoat?

 

[rockyrude]

Re: How to - Remove Anti-Fouling Paint

citri-strip found at the "orange box" does very well and is gentle on the fiberglass, the stripper itself is biodegradable, to bad the anti-fouling paint isn't. in fact it's pretty toxic so handle carefully. one gallon was enough for my 19' trihull.

 

[arks]

Re: How to - Remove Anti-Fouling Paint

My intent would be to take it down to the original gel coast and finish it with 600 grit, 1000 grit, rubbing compound, elbow grease. The anti-fouling paint is really thick, looks like more than one coat and I hate to think about sanding it all away hence the desire to find a good stripper that won't damage the gel coating.

Anti-fouling paint is typically applied initially as 2 or more coats then re-applied over that every few years, so I'm not surprised that it's thick. I'm planning to have my bottom paint removed in the spring and will have it soda blasted, which is less harmful to the gelcoat than sandblasting or grinding. There are companies with mobile equipment that you can hire for the job. They're price usually includes all the prep and cleanup. After the hull is clean I'll be applying 2 layers of epoxy barrier coat, then 2 layers of new anti-fouling. It'll be a busy spring...

I see a few boat owners use this "paint" around here (strickly fresh water by a 1000 miles or so) and I always wonder "what were they thinking"? I wonder if the lake it was on had a problem with alge.

The reason is because slime will delelop and grass will grow on boats kept in fresh water. The correct anti-fouling paint helps keep both to a minimum. My boat is docked in fresh water and I've always used bottom paint.
The only ones who don't need anti-fouling are boats kept out of the water when not in use, like rack stored, lift kept, or trailered.

 

[TK]

Re: How to - Remove Anti-Fouling Paint

This is my experience with bottom paint removal this year on my project boat that was also in fresh water.

I first tried Zip Strip just to see how much paint was on. ZS worked but that stuff is nasty and will harm fiberglass.

Next I ordered up some marine soy strip. It did a real good job all the paint EXCEPT the bottom paint. I tried it cold hot long short every way but upside down. I would recommend Soy for every thing except bottom paint.

Last I took my boat to a boat yard and had them soda blast it off. That is the best way IMO. However there is a Caveat...you will not be able to bring the gel coat back. I knew that before going in. I was going to do a full restore and repaint.

The other interesting thing after the soda blast took the bottom paint off I notice there were a lot of gel coat cracks (hull is 40 years old). In doing research that was most likely caused by the black bottom paint contracting and expanding over the years at a different rate than the gel coat.

This is my story and I am sticking to it.

 

[Moody Blue]

Re: How to - Remove Anti-Fouling Paint

My project was somewhat smaller than yours (16ft deep V hull) but I ran into the same dilemma this past summer.

Tried a number of approaches (sanding, scrapping, power washing etc) with little to no success.

As a last resort, I purchased some gelled paint and varnish remover. After some experimentation I found the secret.

The anti-fouling paint MUST be kept wet with the paint remover. I brushed the stuff on liberally and kept the area wet for about 10-15 minutes. The paint soaked up the remover like a sponge so I just kept applying more. After about 15 minutes, the paint was easily scraped of with a plastic putty knife. I then washed the area thoroughly with soap and water.

I worked in sections about 2 sq ft at a time. The gelled remover works well because it "sticks" to the surface. I did find that the gel coat seemed softer after the remover had soaked for awhile, but did return to "normal" after a short time.

I used a little less than 2 litres (2 quarts ) for the 16 footer. Gloves and eye protection are must haves. That stuff really burns on exposed skin.

 

[bman1bpm]

Re: How to - Remove Anti-Fouling Paint

I just used my palm sander and got to work. It wasn't as terrible as I thought it would be. came off easily, then again most of the paint was so old on my boat it was flaking on its own.

 

[Skizzm]

Re: How to - Remove Anti-Fouling Paint

A little late, but better than never. There is a product called "DeFoul" by a company in Vancouver BC. there is a Youtube video as well under anitfouling removal. You spray it on, wait overnight, and pressure wash off. If you have multi layers, you may need to scrape off excess paint as it will clog up the marina's system, but it comes off right to the gelcoat. Amazing stuff. Non Toxic as well!!!