Chemical bottom paint stripper

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senangsekali

Senior Member
Joined
Jun 19, 2017
Messages
216
Location
Canada
Vessel Name
Senang Sakali
Vessel Make
North Sea 37
I am going to strip my bottom paint this March to remove years of bottom paint. Does anyone on here have experience doing it and what brand did you use. also do you need to barrier coat after chemical stripping.
Thanks
 
Many years ago I did this to a previous boat. What a horrible experience. I used a stripper that you painted on very thick and then covered it with a paper so it would not evaporate as quickly. It didn’t do a great job. It was way more work than I had thought. A different boat that I needed stripping I had soda blasted. What a difference. Yes, if you are stripping the hull, I would definitely do a barrier coat. Cheap insurance and easy to do after the hard work of stripping is done.
 
You will probably be best served by having your hull soda blasted, rather than chemical stripping. Environmental issues with chemical strippers and the mess are going to be an issue pretty much anywhere you do it. Finding a yard that will deal with the whole stripping job is probably wise. It's probably less expensive than you think.

If you don't have a barrier coat, or don't know if you have a barrier coat, you should plan to barrier coat.

That's just my two cents, but I have never heard of anyone chemically stripping bottom paint before...
 
I am unsure if I have a barrier coat at the moment. I was looking at pettit brand. It apparently only requires 3 coats instead of 6.
 
I used a citris brand a friend wanted me to use on his 42 foot sailboat.


The first stripping was miserable putty knifing it off.


Then he remembers you could pressure wash it off. Much better but I am not sure I would want to do a hard chined powerboat.


The stripper itself was environmentally friendly but the resultant residue my not be. But shouldn't be much different than blasting, just the collection might be an issue.


I don't remember the name he had, I just used some Citris based stripper from Home Depot on a topside doorframe that worked well.
 
Citrus stripper from Home Depot works well. I always have it around the house. Having said that, I cannot think of a worse job than using that on the bottom of a boat. The mess would make me crazy. It has to be over 60 or 70 degrees for the stripper to work well. You have to cover it with newspaper or plastic to keep it from evaporating. You will have it in your eyes, ears, and a**hole. If it’s about $$$$, find a way to make a few to pay for sandblasting. Trust me :)
 
The only chemical stripper that I found that will go down to the base coats was peel away. You put it on thick, then cover with a paper to keep it from drying out and then let it sit overnight for about 12 hours. Then you lay down plastic and scoop it off one narrow 2-3 inch strip at a time. Bag up the goo, lay down fresh plastic and do the next strip. Repeat. It will take hours. Then apply the next section or side, come back the next day and you will essentially have it. There will still be a residue, so break out 5he vacuum sander and finish it off.

I tried most of the other chemical strippers like pintoff, aircraft, west, citrastrip and none of them would do anything but just make the top layer a little gooey before they dried out and stopped working. Ymmv, but they are all expensive and may not work much at all. Could not imagine doing anything with them but a small area. I tried to do a small trim tab and just wound up sanding.

Not my recommended method. I’d just pay someone to vacuum sand the whole thing.
 
I stripped the bottom paint off a previous boat, a 31' Island Packet. I used "Peel Away". Lay it on thick, cover with their special paper (or plastic sheeting) to seal from air, let it sit overnight, and start peeling it off with a joint compound knife. The bulk of the paint should come off with the first coat, but several coats may be required. It is messy. You need to lay down plastic tarps on the ground to catch the crap as you scrape it off. After striping, washing, and a light sanding, I applied a barrier coat. Probably the cheapest alternative for hull striping, over sanding, soda blasting, et al. Definitely a "do-it-yourself" option. I did one side one year, the other side the following year.
 
When I had a boat soda blasted it cost $35 per foot.
 
I sanded this summer. Laborious job. Brutal actually. Didn't have much choice as my boat yard no longer allows soda blasting. EPA has stringent rules about collecting residue and it's just wasn't worth the trouble for the yard.

Putting barrier coat on was very easy in comparison.
 
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Had both my boats sandblasted down to the gel coat. One had probably 30 coats of hard bottom paint. Left a nice scuffed surface for the barrier coat to stick to. I would look for a boatyard that still sandblasts.

Ted
 
I'm back now, after reading the words "chemical stripper" I ran screaming from the room and across my front yard. If you got the money soda blasting is the way to go, just point them at the boat and come back later with a check, no gagging or coughing, no gooey mess to clean up, plus you'll live an extra year or so. In truth I do my own using a sharpened stiff putty knife and do 3 or 4 square feet at a time and in a few days it's done. Yes to barrier coat and I'd suggest ablative bottom paint to avoid this fun in the future.
 
I think the by-the-foot price is also dictated by the beam of the boat. For my 30' boat I paid $100 a foot for blasting, barrier coat, and two coats of Trinidad SR bottom paint. It seemed very reasonable to me at the time, just the paint is $500 for two gallons...

My boat yard no longer allows bottom sanding in the yard, they are concerned about the contamination to the ground and other boats nearby.
 
I used chemical striper on the botom of a 37' trawler in 2011. Took me and my brother two days. I used the same stuff I use in my flooring business a Zip Strip product. It worked fast in about 50* weather. The key in my case was a generous coat giving it about 20 minutes before scraping with a sharp scraper or putty knife. The stripper could be neutralized with water so I hosed each section as I went to avoid softening the gelcoat.

You can actually do more work faster with a 1-1.5" tool as long as you keep it sharp. I did have to sand after to get some spots and a smooth finish but was able to move the sander like an eraser on a chalkboard. Used a dust hood and vacuum on the sander. Also had plastic under the boat to catch debris.

Then did 6 coats of barrier. The Interlux rep. recomended I alternate white (I think) and gray barrier coat to make it easy to see any missed spots. A flag coat of black ablative bottom paint then 2 or 3 coats of red ablative.

The hardest part was sanding, it's hard to hold the sander over your head. We did make some low staging so we could lie on our backs, elbows on chest to make it easier. Also wore Tyvec suits and full face respirators.

Good Luck!

Rob
 
The hardest part was sanding, it's hard to hold the sander over your head. We did make some low staging so we could lie on our backs, elbows on chest to make it easier. Also wore Tyvec suits and full face respirators. Rob
We did a hard dry machine sand of our 36ft boat,using only surgical masks for protection,following some hull work. I envy your protection.
Very little a/f build up, the PO had it soda stripped not long before but didn`t do the hull work. A truly disgusting filthy job working overhead lying on your back,took 2 of us a day per side. We got a lovely smooth hull belying the age of the boat. But never ever again would I do that.
 
You should talk to Keith at Blackline in Sidney, seems they have a new way of stripping old bottom paint off, a few members at our club had them do it and were very please.Dont know what the cost was but Keith will let you know, hope this helps.........:thumb:
 
You should talk to Keith at Blackline in Sidney, seems they have a new way of stripping old bottom paint off, a few members at our club had them do it and were very please.Dont know what the cost was but Keith will let you know, hope this helps.........:thumb:
Thanks I will do that. I am hauling at canoe cove, so black line is in the yard.
 
Dustless Blasting

Recommend strongly you check out "Dustless Blasting" on youtube.
I thought seriously about purchasing a unit and going into business stripping hulls, rudders, props. Interested in everyone's thoughts on the technique.
 
Im up for the same job this August what did you do in the end.
 
I am going with chemical stripper. I was quoted 2100 to do a soda blast in Victoria bc. I never started yet. I am going on the hard on March 15. Hopefully I will be up for a week or so. I will updated on how it works out.
 
Recommend strongly you check out "Dustless Blasting" on youtube.
I thought seriously about purchasing a unit and going into business stripping hulls, rudders, props. Interested in everyone's thoughts on the technique.

I have a quote for $2600 (U.S. dollars) 36 Grand Banks. Water with glass beads. Says there is more work setting up for no mess than the actual process.
 
Stripping bottom paint earns a space in the hall of infamy for nastiness. Strippers have chemically changed over the years, decades. It's always been nasty stuff. Do I taste lead?


If the old paint is so well bonded that you need blasting or chemicals to remove it, why bother? I wonder about the necessity of stripping and how much is from the engineering dept and how much is from the sales dept? Boat bottoms take a beating and I guess the only way to be sure is to strip it. But I wonder.


I did it when I was a teenager, long time ago. After decades of involvement in widely varied interests, the nastiness of stripping bottom paint sticks in my mind. Kinda wish I never got near fiberglass insulation either, fumes from welding, yuck.


I also remember seeing unskilled workers sanding paint from aluminum aircraft, tragically stupid. Be careful of who you hire for what. Saving a buck today may not be the end of the story.
 
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I have a quote for $2600 (U.S. dollars) 36 Grand Banks. Water with glass beads. Says there is more work setting up for no mess than the actual process.

Bet this is a pressure washer with wet blaster, sounds good to me. I'd still watch from a distance.


Done this with sand on metal. The attachment is very reasonably priced. The orifice size must be matched to the volume of the pressure washer to maintain pressure.
 
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I think the blasting will allow me to inspect the bottom of a new (to me) boat. Up here where we haul and repaint every year it makes it easier to start with a bare bottom. Start with 2 coats ablative paint and then put a thin coat of (water based) on every year. No sanding necessary. Boat is 35 years old and has been hauled every year. If the bottom is found to be clean with no blisters it won’t start now. I am not going to barrier coat.
 

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