Bottom Paint Removal

[Celestialsailor]

I searched but did not see any direct discussion on the topic of bottom paint removal.
After buying "Faiaoahe" in 2004, I hulled and put a coat of Trinidad on her and watched it blister some. It appeared that this had happened before at some time due to all the peeling that had been covered up.
It has at least 6 old coats on it and I figure I will start new, remove the paint entirely and do a Interlux 2000 epoxy barrier and then Trinidad again.
I had removed bottom paint off a prior boat with a 8" sander and it was pure hell and I'm sure knocked off 10 years of my life. So the topic here is...
What is your DIRECT experience with bottom paint removal. I have seen people in yards using Interlux stripper, Jabsco epoxy stripper and have read a little on Peel-away.
Is there a silver bullet for this somewhere?...Aloha

[island trader]

yes!!! soda blast. like sand blasting ny will not destroy the gelcoat. commerical painters use it.

[Celestialsailor]

Unfortunately they do not allow blasting in the yard where I will haul.

[Alan Wheeler]

So you have done this before and didn't learn the first time huh? I was a faster learner then. I learn't on my first Anti-foul application that it wasn't a job I wanted to ever do again.
Scrape. A blade type draw scrapper is the only other way. But I think I can hear you moan about that from here. Sanding is also hard yakka. But most importantly, you need to ensure you are well protected. Wet sanding tends to be the least harmful, because there is no dust created. But that creates issues with the machine and electricity and you joining machine to the ground your standing on. So air operated sanders are best. But that means you have to have a good compressed air source capable of running air sanders. Which are also heavy users of air, so a big (15Cft free air delivery) compressor is required.
So how does the commerical painter in your area tackle this?

[DGK]

Try a 1.5m torture board, it is the quickest I have found and as alan states, do it wet.

cheers

[Celestialsailor]

I'm not sure what torture board is. Sounds like something large, flat and raspy.
Alan...To be kind, Hawaii is a 3rd world country that speaks english. There is no one that does this commercially on this Island. I am curious though about stripping chemically...again from someone who might have done it.

[Wotname]

Originally Posted by Celestialsailor

.... I am curious though about stripping chemically...again from someone who might have done it.

OK I have stripped antifouling (bottom paint) recently (well, about 2 years back) using chemicals after all else failed (sanding, grinding, blasting etc). The boat had say 25 years of various antifouling paints on it. I estimated 3 days full time for the job, took 6 weeks part time. I figure about 14 full days was the final figure.

I tried various chemicals but the one that worked most succesfully was a locally (Perth Australia) manufactured gel or paste that was principally caustic soda. Worked quite well. It was trowled on about 1/8 inch thick, let sit for say 8 hours and scrapped off with a long handled scrapper (al la Wheels). Then repeat the process and so on. It certainly worked better than other method I tried. The caustic soda is fairly safe around gel coat (but not so safe around humans and certainly very unsafe around Al.) It reasonablly safe on wood (but not all plywoods) but MUST be washed off wood with an mildly acid solution.

I am guessing this similar to the "soda blast" I have heard from USA folk.

Try contacting the local (or mainland) supplier of coppercoat www.coppercoat.com as this is a product that requires the removal of all previous bottom paint. Although you are probably not using coppercoat, they might be able to put you onto a suitable product in your area that will remove the antifouling. That is how I came across this locally made stuff. From memory, it was about $120 (AUD) for 25 kg. and I used that much on a 31 ft boat.

[island trader]

you should ask the yard why? soda is safe! feds like it, it's baking soda. read more ... The Soda Works

[delmarrey]

Have you considered peel away????

DUMOND CHEMICAL 1160 PEEL AWAY NO 1 SIZE:1.25 GALLON PACK:4 PCS. :: DUMOND CHEMICAL :: MANUFACTURERS :: Paint-Colors.net

[emeraldsea]

I just did my'n and found a sharp chisel with the proper pressure and angle worked well. I have a FC hull though, may not be the best for a glass hull.

[Alan Wheeler]

I am guessing this similar to the "soda blast" I have heard from USA folk.

No Soda blasting is exactly the same as sand blasting. Sand is blown by high pressure high volume compressed air. The sand hitting with so much force it erodes away the surface. Soda is a small light weight particle that is not as harsh as Sand. It will errode away softer compounds like paint, but will not harm the hull (if used correctly).
CS, the problem with using chemicals to soften the paints, is that most often these paint strippers will react with the imediate coat it is applied to. So the next layer underneath is not touched. If you have 6 layers or more, then quite often, that results in 6 seperate applications. It simply depends on the build up, the type of paint that was used and how each layer adheres to the next. A test area is the only way you are going to know. And yes, after you apply, you then use a scraper. I am sorry I was not clear on that. We call them Linbide scrapers here in NZ, but I think that is because of the manufacturer and not the actual name as such.
One other way of perhaps doing this is if you can hire a very high pressure water blaster, if they will allow you to do that. Something in the range of 3000PSI will remove the anti-foul paint. Lower pressure may take longer. But once again, you have to try an area and obtain a balance of application to ensure you remove the paint and not harm the hull.

[ozskip]

Hi i have hire shop and the pro fishing boats here use our high pressure water cleaner on cold but if they want to go back to the bare hull they use it on heat 95c and it seams to do the trick.Greg

[Wotname]

Originally Posted by Alan Wheeler

No Soda blasting is exactly the same as sand blasting. Sand is blown by high pressure high volume compressed air. The sand hitting with so much force it erodes away the surface. Soda is a small light weight particle that is not as harsh as Sand. It will errode away softer compounds like paint, but will not harm the hull (if used correctly).
.

Thanks Wheels, I now see why it is considered so benign. Quite a bit different from a concentrated caustic soda application .

[Alan Wheeler]

want to go back to the bare hull they use it on heat 95c and

You just jogged my memory. When I was a wee lad, one of my after school jobs was washing down Tractors and Trucks with a steam cleaner. If they wanted to remove the paint, I wound the temp up and the paint would strip right off. Can't see any reason why Antifoul wouldn't either. Hey you'd have steamed mussel's (if they were growing on the hull)

[turkish6]

I have no experience with chemicals but I have tried sanding and scraping and scraping is by far the better method.