Removing old antifouling applying new gelcoat?

[Leeward Rail]

The only way to remove VC 17 is with a sander and aggressive sandpaper. Been there, done that.

 

[Tally Ho]

I did it once…and I just wanted to get the loose stuff off and rough up the rest to take a nice fresh coat…

Here was my PPE setup.


Still had red dust in my ears, hair, clothes…and my RO sander has never been the same since


Greg

 

[Leeward Rail]

Was just searching practical sailor's website for unrelated stuff and found this page about strippers.

Boatyard Chemical Wisdom - Practical Sailor

Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.

www.practical-sailor.com

Interesting info about NMP and Methlyene Chloride

@rgranger DIY mix sounds better and better.

 

[Leeward Rail]

Still had red dust in my ears, hair, clothes…and my RO sander has never been the same since

My go to is now those disposable suits with the hood.

Depending on application, I now buy cheap sanders and assume bearings will die after a few uses. I havent tried putting foam over the air vents or using an air compressor to blow the dust out periodically during sanding.

Just like using wet/dry vacs with drywall. Even if you install both a good pleated filter and a bag, the dust in the room gets sucked into the armature and will kill the bearings.

 

[dlochner]

I use an Oneida Air Systems Dust Deputy (Amazon link) with a larger shop vac equipped with a filter bag and HEPA filter. This is virtually dust free.

 

[Leeward Rail]

I use an Oneida Air Systems Dust Deputy (Amazon link) with a larger shop vac equipped with a filter bag and HEPA filter. This is virtually dust free.

That is my plan in the future. Lots of the original brand and cheaper clones out there. Would pay for itself after a couple uses if it saves buying a new vac.

I plan on using one when I sand the hull next spring.

 

[rgranger]

Was just searching practical sailor's website for unrelated stuff and found this page about strippers.

Boatyard Chemical Wisdom - Practical Sailor

Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.

www.practical-sailor.com

Interesting info about NMP and Methlyene Chloride

@rgranger DIY mix sounds better and better.

Yes... Methlyene Chloride is bad stuff. Unless you have studied the MSD sheet and know what you are doing, I recommend avoiding any hydrocarbon material that contains a chlorine atom.

 

[rgranger]

@rgranger DIY mix sounds better and better.

It is not without some hazards. DO NOT get this stuff in your eyes. And any skin that gets exposed will become very dry, crack and take a week or so to get right again. The strong base actually turns the oils in you skin into soap and they wash out leaving raw hide where you soft skin used to be.

 

[NYSail]

I used to post on here a receipe for homemade peel away. YOu take a 5lb bag of garden lime, two cups of lye and put it in a 5 gallon PVC bucket. Add just enough water to get a melted peaunut butter consistancy and then roll that on the bottom paint... the garden lime is there just to add a paste that helps hold the potassium hydroxide (lye) to the paint. If it is hot and dry where you live, you may need to cover it with plastic sheeting so it does not dry out before it is done working... some receipes also add glycerin to keep it moist.... a 10lb bag of sugar will also do the same trick but if you have ants or bees around that might not be a good idea. The ingredients are so cheap I'd skip adding sugars and/or coating with plastic sheets and just do it more than once if some of the paint does not come off the first time. Less mess and hassel that way.

Easy off is also just a very strong base, suspended in some binders to help hold it on the surface you are using. But to do an entire boat it will cost you a lot more. A can of easy off is $5 and you will probably need 20 of them. The entire 5 gallon PVC bucket approach is only $15. If you are going to do the entire boat, the PVC bucket way is much less expensive. I've done this a dozen times.... almost all of the paint will sluff off in big sheets... and for some reason there is always one or two spots that won't come off ... so I put a little citrus strip on those spots. Nice smooth bottom without sanding off any gel coat.

Thanks!!

After you do this do you wash the bottom with anything or just rinse? I have been having issues with paint adhering since yard has been doing the work. Think the initial time they painted it was cold and raining and the paint never got hold. Have been sanding and still having issues. Have to try a more thorough removal. And does it just remove the ablative paint and leave the barrier coat fine? Was going to have it blasted, but was quoted $6,000???? Seems crazy for a 43 foot boat.

Greg

 

[Leeward Rail]

It is not without some hazards. DO NOT get this stuff in your eyes. And any skin that gets exposed will become very dry, crack and take a week or so to get right again.

Hehe. I would traditionally figure that would be obvious, but with younger generations I am not so sure.

This stuff strips paint = likely not good on skin eyes or to eat.

But hey, they have labels warning about sticking aaa batteries in your ear.

The sad thing is that warnings have become so common that people ignore them even if they are actually important. Most of the guys at the shop were warned about the nasty stuff but would often assume it was fear mongering.

"Yes.. The very strong nitric acid is in a container, in a container, in a plastic zip bag for a reason.. No you don't want it on your skin.. No I mean seriously.. No."

 

[Leeward Rail]

Was going to have it blasted, but was quoted $6,000???? Seems crazy for a 43 foot boat.

How were they blasting it?

 

[shemandr]

After an hour or two of sanding that 6K might not look so bad.

 

[rgranger]

Thanks!!

After you do this do you wash the bottom with anything or just rinse? I have been having issues with paint adhering since yard has been doing the work. Think the initial time they painted it was cold and raining and the paint never got hold. Have been sanding and still having issues. Have to try a more thorough removal. And does it just remove the ablative paint and leave the barrier coat fine? Was going to have it blasted, but was quoted $6,000???? Seems crazy for a 43 foot boat.

Greg

It really works well... does not touch the gel coat. I have fully restored seven sailboats... and have helped a half dozen friends work on theirs... The first time I tried this receipe was on my third boat.... so... that means I have sanded at least three sailboats and know what a PITA it is.... when I did this the first time and hit it with the pressure washer... I just started laughing. The paint just sluffed off in big sheets. It was a very pleasant surprise.

The paste's main function is to keep a moister level on the hull's so the strong base can break down the paint molecules. It is so cheap that if you have any spots that didn't come clean, just do it again.

I used one of these to apply it

Just mash it down in the PVC bucket and roll. It takes less than five minutes to cover the bottom of your boat. If you have a boot stripe you want to keep, tape it off first.

Go have a beer (or three) and come back with the pressure washer. A cool, overcast day is better because the paste won't dry so fast. Once the paste is dry, the chemistry stops happ-nin' .... over time I got in the habit of rolling the paste on near dusk and letting it sit over night. Pressure wash in the morning.

Here are three pics.... the first is the before... the second shows the dry paste on the hull... and the third is after a pressure wash. You can see a few spots that did not sluff off. I just did it a second time. Every now and again, you will end up with one or two spots that just "stick"... I hit those with a little citrus strip and use a putty knife edge to get the last bit off.

 

[shemandr]

You could start a business - sandingsucks.com

 

[dlochner]

You could start a business - sandingsucks.com

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