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Antifouling paint stripper


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Our sailing co-op is considering using paint stripper to remove many years accumulation of hard bottom paint. 

Anybody done this and how happy were you with the results? This is a Catalina 27 with probably 6 - 10 layers residue.

Local costs for Dumond Safety Strip would be about $600 (a gallon only covers ~20 ft^2)

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The bottom is really really rough on some of the boats. Very patchy and flaking off in big chunks because it's so thick.

Every year we sand residue of the previous layer of hard paint but the cheap labour (co-op members) is lazy and doesn't always do a good job

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I've done 2 buddies boats this way. It's messy but works well. Use tarps under the boat and full tyvek suit/hood/goggles to protect yourself

The secret is to work in the early morning moisture so the stripper doesn't dry out on you otherwise it loses effectiveness and you end up using much more.

A hot day is the wrong day. 6-7 layers is a lot and may require a few runs of stripping but it will get the job done. You'll still need to sand some areas where the stripper didn't get to but easier than sanding the entire boat.

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45 minutes ago, Zonker said:

The bottom is really really rough on some of the boats. Very patchy and flaking off in big chunks because it's so thick.

Every year we sand residue of the previous layer of hard paint but the cheap labour (co-op members) is lazy and doesn't always do a good job

So much for that idea. If they're too lazy to sand, they're too lazy to scrape.

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Did mine this past winter.

Use a pull scraper and keep the carbide blades sharp to get the really ugly stuff off.

Tarp on ground to catch the debris.

Should take maybe an hour.

 

Then roll on a stripper from a pan and a 3/8" roller cover.  I just took 7 years of Pettit sr60+ off with Citrus Strip from Home Depot/Lowes. Shitload cheaper than anything with an anchor on the container, and no fumes.

The trick is to press a layer of plastic sheet on it while wet.  Thin film is fine, but I like the slight thicker stuff so the wind does not fuck with it and use the 4 foot  wide stuff so I can peel back a manageable area . 

https://www.homedepot.com/p/HUSKY-3-ft-x-100-ft-Clear-4-mil-Plastic-Sheeting-CF0403C/202184120

Tape top against the hull well with masking tape so it does not fall off.

Let it set overnight.  In the morning peel only about 2-3 feet at time and using a pull scraper pull down.  I keep a 2 gallon pail to flick the dissolved paint into so the tarp below does not become a slimy mess.

Then a light sanding with 80 grit  on an orbital with the hose to a dust deputy and ultimately a shop vac.  The dust deputy will grab 80 percent of the residue.  If rolling without a barrier coat rebuild, one last pass with 150-180 followed by a hosing/wipe down and you will be set for another decade.  Next time it will not be your problem.

 

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zonk,

I used some whale snot stuff on my moody when i was working on the hull last year.  30 years of AF.  it was working.    it was peeling the old Ablative off.  but it was taking a while.. when I get home tonight  I'll take a pic of the 5gallon bucket were were using.

in some areas  the pain peeled right up.  in other spots not so much.  but I think that might have been applicator error...

the down side, is that   it felt like you were working with, whale snot.  it was slipper gooey, got everywhere, and kind of a nuisance.  forever slow has the technique.  Id also add the very wide flexible putty knives with the ouder edges rounded to minimize gouging   to the tool arsenal.

 

if you were closer and stateside,  I'd send you what i've got leftover...

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I used Peel Away on two different boats and it has worked very well. It is very thick and is applied with a trowel 1/8 to 1/4 thick, then covered with the provided paper to slow evaporation. Let set for a long time, test to determine the time required, it could be 24 hours or more. Peel down with a putty knife and the paint sticks to the paper so clean up is easy. Takes off multiple layers of paint. Be sure to neutralize. There are two varieties, be sure to get the right one for your bottom paint. It is relatively expensive, Defender had the best price and it takes a lot to get the job done.

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I have made my own for cheap using lye powder, corn starch and warm water.  Worked a treat if you can keep it from drying out.  As with most things, the prep work was the hard part and the actual removal of product was easy.  I then pressure washed to neutralize and sanded.

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Listening to the hassle here and thinking about the net cost for a couple gallons of the stripper... has me wondering if it's not time to call the soda blaster, drop the money and spend the bottom stripping day in a local sports bar drinking beer and watching the  baseball / football / hockey of your choice.  With Tyvek suits, scrapers, trash bags and everything else, it has to be getting close to the cost of a soda blast.  

I have a 35' boat and do the racing bottom each year, sometimes coarse sanding down to the Interprotect before spot re-fairing, and the amount of work you guys are suggesting makes my back hurt more than that just to think about it. 

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We've tried several stripper methods & products in our yard over the years. But the effort, mess, PPE and pretty substandard job in the end made us go back to Soda Blasting. Cheaper in the long run, safer, easier and better job for sure. YMMV

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2 hours ago, charisma94 said:

We've tried several stripper methods & products in our yard over the years. But the effort, mess, PPE and pretty substandard job in the end made us go back to Soda Blasting. Cheaper in the long run, safer, easier and better job for sure. YMMV

Yes

the paint strippers are a mess

on a small boat , in which you may need to crawl under the hull , it’s a nightmare 

i would prefer to dry scrape with a sharp push scraper 

blasting is the best solution .. many folks have this equipment 

a blasted bottom is not expensive 

 

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On 9/21/2021 at 8:36 AM, sailorman44 said:

I used Peel Away on two different boats and it has worked very well. It is very thick and is applied with a trowel 1/8 to 1/4 thick, then covered with the provided paper to slow evaporation. Let set for a long time, test to determine the time required, it could be 24 hours or more. Peel down with a putty knife and the paint sticks to the paper so clean up is easy. Takes off multiple layers of paint. Be sure to neutralize. There are two varieties, be sure to get the right one for your bottom paint. It is relatively expensive, Defender had the best price and it takes a lot to get the job done.

the peel away you get from Home Depot is chemically the same as the stuff you get from your chandelry.

Only the paper does not have the little anchors on it. I checked the MSDs and the called the folks in Long Island.

Same stuff,  just a premium for the anchors on the paper if you are so inclined.

and the stuff does not work below 40 degrees.  The folks there laughed at me when I asked why it was not working in the middle of winter in New England.

I find Citrus Strip works better and is MUCH easier to apply provided you use a 3/8" roller and not a paint brush.  Then lay on a sheet of plastic.

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  • 4 weeks later...

hot air ? they make heat guns for that

back in the stone age I used a blowtorch on a wood chriscraft  bottom

it worked the paint would soften then bubble hit it then or it will bake and not come off

but at the right temp it came off in big sheets fairly eazy

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On 9/25/2021 at 2:37 AM, charisma94 said:

We've tried several stripper methods & products in our yard over the years. But the effort, mess, PPE and pretty substandard job in the end made us go back to Soda Blasting. Cheaper in the long run, safer, easier and better job for sure. YMMV

That's what our local yard says. They don't strip bottoms any more. They refer you to a soda blasting contractor who comes in.

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You're a club.  There's multiple boats.  Offer a deal for some free advertising eg "sponsored by Bob's blasting"or a tax credit(if possible).  Not sure if it's the same as for a charity.  Call a few blasters, find out their slowest time of the year, have all the boats ready to go.  Blast and be done.  The liability in volunteers and drippy goopy stick shit that can cause injury doesn't seem like fun.   Stands and tapping could all be set up for 2x boats at a time, blaster alternates back and forth, volunteers do the setup and teardown/cleanup.  

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On 9/25/2021 at 2:37 AM, charisma94 said:

We've tried several stripper methods & products in our yard over the years. But the effort, mess, PPE and pretty substandard job in the end made us go back to Soda Blasting. Cheaper in the long run, safer, easier and better job for sure. YMMV

I have tried everything mentioned, Soda Blasting is the way to go. BTW if there is a barrier coat the blast wont effect it.

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On 11/12/2021 at 10:14 PM, Black Dog said:

I have tried everything mentioned, Soda Blasting is the way to go. BTW if there is a barrier coat the blast wont effect it.

After antifoul removal it’s recommended to apply an epoxy substrate primer before antifouling 

antifoul adhesion is greatly improved 

Pictured is the classic antifoul adhesion problem 

the black colour is epoxy barrier coat 

 

8B75EED8-A534-4BA4-9E40-6C424D8E216E.jpeg

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Picture above is a classic case of missing over coating window. If you get the timing right after epoxy application the antifoul with etch itself into the epoxy. If you miss the window and the epoxy is cured, the antifoul just sits on the epoxy as appears in the picture.

Rule of thumb, if you've applied your epoxy, in 3-4 hours you press your thumb onto the epoxy, if it (the epoxy) comes off on your finger, it's too early... If it just leaves a fingerprint, you're good to apply the antifoul.

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5 hours ago, charisma94 said:

Picture above is a classic case of missing over coating window. If you get the timing right after epoxy application the antifoul with etch itself into the epoxy. If you miss the window and the epoxy is cured, the antifoul just sits on the epoxy as appears in the picture.

Rule of thumb, if you've applied your epoxy, in 3-4 hours you press your thumb onto the epoxy, if it (the epoxy) comes off on your finger, it's too early... If it just leaves a fingerprint, you're good to apply the antifoul.

Yes indeed , 

boats are typically antifouled outside , in the spring 

many chances for a “ mistake “

a classic contamination is morning  dew running  down the topsides and contaminating the bottom 

 

 

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