Removing all layers of antifouling

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cmedsailor

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Is there any easy way to remove all layers of antifouling until you reach the primer or the epoxy layers without removing those?
When i had my boat epoxy treated some years ago i thought of removing all antifouling on every lift out without damaging the epoxy paint so that i don't end up with 10+ layers of antifouling in some years. But i never did so far. It seems impossible to do it using sand (or usually wet) paper. But is there any other method?
 
cmedsailor said:
Is there any easy way to remove all layers of antifouling until you reach the primer or the epoxy layers without removing those?
When i had my boat epoxy treated some years ago i thought of removing all antifouling on every lift out without damaging the epoxy paint so that i don't end up with 10+ layers of antifouling in some years. But i never did so far. It seems impossible to do it using sand (or usually wet) paper. But is there any other method?
Click to expand...

Soda blasting ??
 
We do not have any sand blasting companies up on the North East Coast so had to do my own.

There is nothing easy or quick about removing old antifoul,as jobs go it ranks alongside cleaning out a blocked heads ! did my hull three years ago, started with a tungsten carbide tipped scrapper but within two hrs was grinding with a orbital sander using 40 grit paper, after all the antifoul is removed just jet washed off and let the hull dry out, then sanded again using 180 grit paper, jet wash again, then clean down with thinners.

Do not underestimate antifoul dust, kit up wearing a good quality mask and goggles!

Do not apply any 2 pack epoxy coatings unless you have at least 5 deg C IN THE NIGHT !! and say 8 deg C plus in the day! or you will regret it!

Happy sanding

Mike
 
I did my 30 foot boat 4 years ago. Used a tungsten scraper to scrape the years of antifoul off. A very tough and unrewarding job - I would be reluctant to face into it again. I did try using several recommended concoctions (most are soad caustic based) but I found them to be of limited benefit and they make a hell of a nasty, sludgey mess. So stuck to the scraping - mind you it was over the winter as boat was out of the water, so just did a few hours at weekends. Antifoul is nasty stuff, so I did not want to go down the sanding route. Scraping also means its easier to collect the stuff and dispose of appropriately. Once all antifoul removed, I recoated with several layers of epoxy -I would recommended you also do that if you can. Then prime and antifoul.
 
Guys (Mike and Spacecyggnet),
what you have explained me implies removing of everything and applying epoxy as well. I had a professional did that in Jan.2010. I don't want this. I was referring in a way to remove only the antifouling on every lift out. But it seems that the only way to do it myself is using a water paper (or very very very carefully a scraper). I think I will just forget about this idea because it's sounds impossible and stick with normal antifouling and removing everything every 5-8 years.
 
cmedsailor said:
Is there any easy way to remove all layers of antifouling until you reach the primer or the epoxy layers without removing those?
Click to expand...

Yes. Go with Ellesar or another. I've scraped boats clean myself and I've had them blasted. I'm not made of money and am happy to do most boat jobs myself from engine strips and changes down to mast spraying. But one job I will always now pay someone else to do is stripping antifoul - scraping it off is mindless, boring, and difficult.

Save the interesting mechanical and electrical jobs for yourself. Pay someone else to do the mindless.

Not that I'm suggesting anything Ellesar :o
 
I have used the hollow scrapers sold for the job, attached to a vacuum cleaner that withdraws most of the debris. It is pretty hard going but far more effective than any abrasive paper method. Grinding the corners off the blades helps to prevent them digging in and damaging the hull.
 
I found that scraping 1 year of antifouling difficult. Nothing for the scraper to hook on to.

After 5 or 6 years of coat on coat, it came off in chips and was much easier.

Prepping for coppercoat last year and needing to get back to clean GRP we used a varnish stripper fom Toolstation. No caustic soda and you can wash your hands in it with no problem. Means that you do not need an NBC suit! Messy and slow, but it worked.
 
I would also advocate the soda blasting, gets it all off and if the epoxy is in good condition , it won't harm it , but often it's getting to the end of its life and so should be at least topped up before the new antifoul. That's what we did and so far, four years later are pleased with how it worked out. Wouldn't have liked to have had to tackle it by hand.
 
I have used the Perago rotating scraper (google) with good results. Leaves the epoxy layer intact, just a little dull. This method is rather slow but a lot less work than scraping by hand.
 
A few years back I stripped my 28 ft back to the epoxy barrier so as to Coppercoat. I used a Kaarcher pressure washer with sandblasting attachment and it took a week and a lot of sand! The main problem was the UK weather as any dampness in the "kiln dried" sand clogs the pipes. Obviously the equipment is not the same scale as the professionals use and the working area is only around a 1 inch diameter, but that does give more control. We were able to stop at the interface, but chose to open the texture of the first coat of epoxy as a key for overcoating. To reduce the risk of damp getting into the sand, we abandoned the bucket supplied and just cut a hole in the sandbag and shoved the pick-up pipe in. My beautiful assistant (Dave) held the bag and ensured the end of the pipe remained in the sand.

The main downside is that you build up a thick layer of contaminated sand under the boat. We failed to effectively clean up - and I'm not sure where we could have disposed of it anyway - but for some time after all our neighbours were complaining of sand appearing everywhere, trodden into their boats. I did quite a bit of hoovering and donated doormats to the neighbours. The bonus was that despite wearing everything I could to protect myself, my face was beautifully exfoliated by the splash back. A bit of moisturising cream and I had that Summer look even in early Spring.

Rob.
 
rob2 said:
A few years back I stripped my 28 ft back to the epoxy barrier so as to Coppercoat. I used a Kaarcher pressure washer with sandblasting attachment and it took a week and a lot of sand! The main problem was the UK weather as any dampness in the "kiln dried" sand clogs the pipes. Obviously the equipment is not the same scale as the professionals use and the working area is only around a 1 inch diameter, but that does give more control. We were able to stop at the interface, but chose to open the texture of the first coat of epoxy as a key for overcoating. To reduce the risk of damp getting into the sand, we abandoned the bucket supplied and just cut a hole in the sandbag and shoved the pick-up pipe in. My beautiful assistant (Dave) held the bag and ensured the end of the pipe remained in the sand.

The main downside is that you build up a thick layer of contaminated sand under the boat. We failed to effectively clean up - and I'm not sure where we could have disposed of it anyway - but for some time after all our neighbours were complaining of sand appearing everywhere, trodden into their boats. I did quite a bit of hoovering and donated doormats to the neighbours. The bonus was that despite wearing everything I could to protect myself, my face was beautifully exfoliated by the splash back. A bit of moisturising cream and I had that Summer look even in early Spring.

Rob.
Click to expand...

I need to advise caution here. Ordinary sand is illegal to use for snadblasting becuase it is very dangerous.

Sandblasting works by splitting the grains on impact. Using sand is as dangerous as asbestos. I don't know what tests there are for silicosis and I hope you're OK.

Take care.........
 
Check out a marine stripper. SeaHawk makes a bottom paint stripper meant to remove just the bottom paint. From what I know the secret is to keep in moist; it also depends on the number of layers you need to remove as to how long it needs to "work".
 
Sorry I misunderstood what you want, since totally doing mine 3 years ago I have lifted 'out' after over two years 'in'.

All I will do now after jet washing and drying is to 'lightly' go over the antifoul with 180 grade paper on a sander, but almost like wiping it over with the sander this is to create a 'key surface' then jet wash off, allow to dry, wipe over with thinners.

Then 1 coat of primer plus 2 coats of antifoul over the primer and that's it done for another two years!

Mike
 
cmedsailor - if you do get back to the epoxy save yourself future trouble - coppercoat it. might not be quite as effective as the best anitfoul IMO but at least you dont have this issue every 5 years.
 
Elessar said:
Ordinary sand is illegal to use for snadblasting becuase it is very dangerous.

Sandblasting works by splitting the grains on impact.
Click to expand...

Thanks for your concerns, but in a slurry blast the sand is simply abrasive surely? With a Kaarcher attachment, the water flow sucks up dry sand into the flow in a similar manner to the capillary action of a paint spry. Again, just checking - illegal? What law?

Incidentally, I wore a mask, goggles, gloves and full boiler suit.

Rob.
 
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