Antifoul removal

MJWB

MJWB

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Hello all. Coates of antifouling eventually build up.
How long should one go before removing the lot and starting again?
How do you remove it?
Once off, how do you treat the hull, what checks are worth doing before starting to re-coat?
 
If it's got to the stage where loads of big flakes have come off, and the surface is looking very uneven, you may want to remove the lot and start again. But it's very much a cosmetic issue, and if you're not planning to go racing then some imperfection in the surface isn't going to matter.

If you decide to remove it, and wish to retain your sanity, get someone to shotblast it off. It can be done very gently and won't harm the gelcoat. Then it's sanding, epoxy primer and new antifoul.

In future, if you use eroding antifoul, the build-up of paint shouldn't be too bad.
 
pvb said:
If it's got to the stage where loads of big flakes have come off, and the surface is looking very uneven, you may want to remove the lot and start again. But it's very much a cosmetic issue, and if you're not planning to go racing then some imperfection in the surface isn't going to matter.

If you decide to remove it, and wish to retain your sanity, get someone to shotblast it off. It can be done very gently and won't harm the gelcoat. Then it's sanding, epoxy primer and new antifoul.

In future, if you use eroding antifoul, the build-up of paint shouldn't be too bad.
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Many thanks.
 
The only happy sailors I know are those who paid someone to do the job. Some people have had success with chemical strippers plus quite a lot of hard work. I had mine blasted after about 14 yrs, but there are no hard and fast rules about when it should be done. For most of us it is when we get fed up with a rough bottom and bits flaking off.
 
I removed 50 years worth of antifoul from my boat. Tried using a paint stripper, didn’t work too well and softened the gel coat. In the end, it took about 5 days of hard graft with scrapers to get to off. And that’s on an 18 foot full keel boat. I will not b repeating the exercise: if I ever need to remove antifoul again, I’ll find the money to pay someone else to do the job!
 
Removing antifoul - that has built up is a job you only ever do once! I did it on my last boat.

Last year I had my current boat professionally blasted back and Coppercoated. Ran a brush along the waterline , I have been afloat all winter, last week and the stuff on the hull fell off. I am having the boat lifted for a wash and anodes checked soon will save about three days prepping and paining #priceless
 
Sandy said:
Removing antifoul - that has built up is a job you only ever do once! I did it on my last boat.
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Maybe I'm a masochist but I've done it twice by hand on this boat once 10 tears ago to remove 20 years or so buildup and epoxy and again a year ago to remove 10 years after new yard idiot blasted holes in it. Only takes around 3 days on 38 ft boat (allowing for beer breaks) and another day to prime with vinyguard. I'm happier keeping my money for beer.
 
I found someone saving up to buy a house with his girlfriend and wanting to earn some extra money.. His Saturdays were free and I paid him to scrape it off over a few weekends. I can't remember what it cost so it can't have been very much. It isn't skilled work warranting a high price.

Worth every penny.
 
One of the guys in our club yard sands his every year but while modern stuff is not that toxic I still think there is far too much very fine dust for safety,we tend to let it build up and while it is self eroding stuff we still tend to take it back down to the epoxy base coat every 7-9 years. I have tried srtippers but they just make a tedious job into a really slow and nasty one. So two of us each with a Baco scraper about 2 hours a day for about thee days clears a side. I think it may be faster now because when we first scrape each boat we apply a few coats of epoxy.
 
I think one extreme or the other is best, so when you get back to Gelcoat either primocon or similar plus no more than a couple of coats of soft, eroding antifoul (3 or 4 on leading edges and around waterline). That way most will be gone by the time you next come to do it. Or at the other end of the scale coppercoat, some people have had bad experiences with it and of those who do it's sometimes not really obvious why. If you go down the coppercoat route it's relatively expensive but (assuming it works, which I think is most of the time), you can forget about antifouling for ten plus years. There is still a need to abrade it every few years to reveal fresh copper and there is still a build up on the hull but, again if it's working properly, you can literally sponge it off while the boat is still in the water. I use a scrubbis for this purpose, which I found in the marina skip but it works pretty well. In the past I've also tried applying hard racing antifoul thinking I'll be able to leave the boat in the water longer and scrub the hull more aggressively but in the end I don't think you gain very much doing that.

If you are going to hand scrape the hull, as Quandary says, Bahco scrapers are much better than others - the one with the ball on for extra purchase...
 
^^ With a good vacuum sander there is VERY little dust. I've never seen anyone wet sand in the US, and believe me, the EPA has boatyard rules. Often the boat is tented (but not tightly) and the ground is covered, of course. If you are doing it right, both you and the tarp stays clean.

That said, I use a 2-year ablative paint, in-water scrub a little, do a little sanding every time, and thus it does not build up.
 
I used a Bosch electric scraper on my Dehler 36CWS and it was a really easy job. Regretfully no longer available new but there is one on Ebay ---search for "Bosch Electric scraper"
 
Graham376 said:
Maybe I'm a masochist but I've done it twice by hand on this boat once 10 tears ago to remove 20 years or so buildup and epoxy and again a year ago to remove 10 years after new yard idiot blasted holes in it. Only takes around 3 days on 38 ft boat (allowing for beer breaks) and another day to prime with vinyguard. I'm happier keeping my money for beer.
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I've done it a lot of times. 4 boats which were badly affected by "rippled" antifoul build-up and 3 which were not so bad. I don't mind doing it
 
anoccasionalyachtsman said:
Sanding it back every year is the way to keep on top of it without too much (back) pain.
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A few years down the line, lung problems are likely to be much worse with any fine dust, toxic or not, than short term back pain. I only sand the small thin patches left after scraping and use good dust extraction with HEPA filter.
 
Graham376 said:
A few years down the line, lung problems are likely to be much worse with any fine dust, toxic or not, than short term back pain. I only sand the small thin patches left after scraping and use good dust extraction with HEPA filter.
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As I said in #13, full face mask and a vacuum cleaner deal with the dust. I have very good reason to take care of my lungs...
 
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