Bottom paint

Irek

.
Feb 28, 2021
14
Hunter 40.5 Vancouver BC
Hi everyone
I have just purchased this boat and it seems that there are 27 years of AF paint on the bottom. Plan is to remove it but how? Is there an alternative to scraping? safe for the gel coat?
Another question, does anyone know what kind of protection osmosis coating was applied by Hunter before delivery? A couple of months ago a pre-purchase survey showed the hull in very good condition. No sign of bubbles, and chalking, or soft spots.
My plan is to remove old paint and apply one coat of the same anti osmosis paint that Hunter originally used (but what kind of paint is it?) before applying new ablative AF paint.
Anyone did that kind of work? How did it go? Any info will be appreciated as a significant bill is hanging in the air.

brgds/ik
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
Neither Hunter nor any other manufacturer puts bottom paint on their boats - that is done post delivery and usually by either the commissioning yard or the owner. Same with barrier coat which isn't "paint" but rather an epoxy coating.
There are a few options to remove old bottom paint - from chemical strippers to sanding. There are all kinds of how-to's on the internet you can review. Your choice. Both easily DIY jobs. When we owned a 40.5, it took slightly less than 2 gallons of bottom paint to cover the hull, keel and rudder - same with the barrier coat. The selection of which paint is dependent almost entirely of your sailing venue and what type and blend is most effective in that environment. Check with the locals.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Hi @Irek and welcome to the site.

Another question, does anyone know what kind of protection osmosis coating was applied by Hunter before delivery?
1. What does the bottom paint look like and why do you want to remove it ? Mine is ablative, 22 years old and in good tight condition.

2. Is the bottom paint ablative (soft) or hard ?

3. Hunter did not apply anything from the factory.

If you're doing this job yourself, your first move here is to aquaint yourself with bottom paint. You're getting into a complex undertaking. Not to worry, as it's just something you've never touched before. However, seeing as the boat is a 40.5, you do not want to learn on this boat.

If the paint is ablative, it will be scraped and it's not a bad job. I did my H-310. A 40.5, many more days. If it's hard, it will be air blasted by a pro with any number of abrasives.

The next step is an epoxy barrier coat and there are several. Five coats for most. The bottom must have been sanded to pure white.

As you're in the Vancouver area and most likely at Granville Island, their boat yard has several reliable contractors who are well equipped to do the job. I would strongly recommend using one of them as it's just not going to work as a DIY without experience on a smaller boat.
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
I have restored seven old sailboats and did the bottoms on each. Also helped a few friends out. Here is a trick I learned long ago and for about $10 and an afternoon with a pressure washer, you will have all of that paint off of the bottom.

This is a receipe for homemade peel away.
Go to one of the big box stores (Lowes, Home Depot) and get a 5lb bag of garden lime. Next get about two pounds of either sodium or potassium hydroxide (Canning lye or drain-O). Put both into a 5 gallon PVC bucket and add just enough water (with stirring) to get a consistency similar to melted peanut butter. Roll this onto the bottom with a paint roller on a long pole. Let it dry and then blast it off with a pressure washer. You may need to do it twice for a few stubborn spots.

If you want to capture the toxic paint chips, you can lay an old sheet under the boat while you pressure wash. It will filter and capture the chips.

DO NOT LET THIS STUFF GET IN YOUR EYES!!!!! And wear rubber gloves.
 
Jan 24, 2017
666
Hunter 34 Toms River Nj
if you plan to remove all old paint and diy rather then sand blasting by a professional and paying a lot of cash to have it done. If you have the time and elbow grease to diy then try sanding it with miracle eraser strip and sand blocks.
You can buy them directly at Miracleeraser.com or Amazon for about $30 a pk.

I used these about 20 years ago when I had to strip all the bottom paint off. These blocks are like a pumice stone that slowly melt away / disintegrated as you sand. I believe that they are made of some type of carbon/ graphite material. They work amazingly well. Unlike sand paper that clog and gum up after about two minutes on an orbital sander, these blocks never clog because they slowly dissolve as you sand generating a new sanding surface with every pass. As you sand they conform to the shape of the hull. Again they work amazing. I have to warn you!!! They smell awful, like rotten eggs, and creates a lot of dust. You might have to lay tarps and tarp off the boat in a shroud to use them. Not a big deal as most service yards will most likely require you to do it any way under epa laws.

anyway this blocks work fantastic and can be used wet or dry. I believe they are sold in packs of 18 and two packs will probably be enough. Unfortunately the don’t last long as they disintegrate fast. Miracle Eraser® Strip 'N Sand™ - Paint, Varnish, and Rust Remover for Wood and Metal - 18 Pack
 

Irek

.
Feb 28, 2021
14
Hunter 40.5 Vancouver BC
Hey guys
A lot of interesting advise. The main, Hunter did not applied anything, therefore it must the dealership who handled the delivery. Soda blasting would be great but no marina in North Van will allow it. Need to go to Granville. Interestingly, they claim environment protection but Granville somehow doesn't have this problem.
I have been looking at Peel-away supplied by Dumont. Problem is that they want you to make the test patch with four of their strippers and select the one that works. Only then they will deliver it. But how to do on the boat in the water? Clearly they are oriented on the shore applications.
Very interesting, i guess for everyone, fm "rgranger". It might be worth to try but on the smaller size boat first and see how it works.

Anyhow guys, many thx for yr opinions I am pleased I have joined yr forum. It encourages me to ask question about autopilot on a separate stream.

Cheers! and happy sailing!/ik
 
Jun 4, 2004
1,071
Hunter 410 Punta Gorda
Soda blaster better than sandblaster. Big job to sand it off. Never heard of the stuff mentioned above making a paste but if it works great.
 

Irek

.
Feb 28, 2021
14
Hunter 40.5 Vancouver BC
Hi Dennis
Tku for yr input. There are different mediums but the question is how it will affect the gelcoat. And can you leave it as it will come out of the blasting or you need to redo it. In our area service companies are suggesting scraping off the old AF manually with sharp tool to make sure no special treatment will be required. That means roughly 40 man hours on the 40ft boat or CAD 4k at least, less yr own input. But one will not need to redo with 5 to 6 coats of epoxy. Maybe just 2 coats to refresh the protection, cover up scratches. I believe that even if Hunter did not apply any osmosis barrier on delivery from factory, mostly dealership applied something. In November during the pre-purchase inspection hull was sound, no bubbles, no softening or chalking of the surface. Surveyor did his hammering job and declared good and sound for insurance company report.
So the balance is: if you go with blast it will cost CAD 2k and 1.5 day work but you may need another CAD 6k on redoing the gelcoat after blast. No inexpensive way out. At least CAD 10k for the bottom treatment./ik
 
Aug 1, 2011
3,972
Catalina 270 255 Wabamun. Welcome to the marina
You would be a very rich person of you worked out a way to peel it off in the water.