Antifoul removal

[Matt]

What's everyone's experiences of antifoul removal?

I don't think I'm up for DIYing it with a scraper & paint stripper - it looks like an awful lot of effort to get back to a decent surface.

So I am thinking about getting it blasted. I think it'll be wet grit blasting (the guy on site does that) over soda or CO2 blasting.

What sort of surface finish does that leave in terms of then getting the hull back to a "clean" state - would I be able to go straight in with 1200 grit & then the polisher after?

Thank you.

[Nasher]

Matt

Hi.

I believe the Wet Grit will still leave a surface which is more ideal as a key for applying Antifoul or any other type of paint.
It will be even though, so would be a good start for polishing by machine.

The Soda or CO2 will be less harsh, and may not be completely successful, but will leave a better surface for a less time consuming polish.

I'd love to be corrected on the above, which was passed on to me by The Hayling yacht company, as I'd like to get the last of the AF off my own hull.

[Matt]

Would you say the wet grit would be something like a 400 grit wet & dry finish? Or are we saying more coarse - 120? 240? 40!!!!? I could re-antifoul it, or paint it - but I'd probably rather not and just have it in gel.

[Nasher]

From what I understand, yes something like 4-800 grit rather than anything more course.

But not a Matt-polished surface like 1200grit would give.

[beamishken]

I've had good success with washing off antifoul with standard cellulose thinners a rag soaked in thinners & held on softens it & it wipes off to whatever finish is on the gelcoat. Seems most folk dont go to town with keying before antifoul application blasting will leave a matt finish which will need sanded by hand or machine down to 800 or 1000 is good enough to polish from with a rotary polisher. Its not like a topsides where you want a perfect finish

[Matt]

Mmm. I've got a few litres of cellulose in the garage, I'll give that a go. Thanks.

[Nasher]

Originally Posted by Matt

Mmm. I've got a few litres of cellulose in the garage, I'll give that a go. Thanks.

Matt
If it works.........

How much do you charge per meter of hull?

[beamishken]

Originally Posted by Matt

Mmm. I've got a few litres of cellulose in the garage, I'll give that a go. Thanks.

Need to keep the rags soaked not just damp & they get saturated with antifoul after a while so need a good supply of rags

[Matt]

Originally Posted by Nasher

Matt
If it works.........

How much do you charge per meter of hull?

It's an exponential charge rate

[willk]

Originally Posted by Matt

It's an exponential charge rate

IIRC it's extremely bad for one's health as well.

The will to live can slip away around the third square meter...

[Orwell boy]

Originally Posted by beamishken

I've had good success with washing off antifoul with standard cellulose thinners a rag soaked in thinners & held on softens it & it wipes off to whatever finish is on the gelcoat. Seems most folk dont go to town with keying before antifoul application blasting will leave a matt finish which will need sanded by hand or machine down to 800 or 1000 is good enough to polish from with a rotary polisher. Its not like a topsides where you want a perfect finish

Follow this advice above and you will be happy ,i have done this 3 hulls over the years and it just comes down to what the prep was like before the first coat of antifoul .i had a sports boat that had been done with an 80 grit angle grinder ,but retrieved it going thru the various grit papers ,but had a barn then so spent a whole winter on it ...................but this is the info you must not ignore !! the makers of CT1 make a safe stripper called peel tec ,it is brilliant on antifoul ,i bought six cans for a 6.5m hull and had two left (12/14 £ a can wickes i think ), some just seem to paint the hull over the gell coat which makes it easy if your lucky ......either way go and buy a aerosol of peel tec ,go sparingly and you may be shocked ,what i found is some types of antifoul comes off a treat with BK,s thinners and the peeltec gets what wont shift
good luck

[Matt]

So I had a chat with the guys at the yard yesterday about removing antifoul.

They said even the mildest wet grit blasting will need quite a bit of repairing and making good if I wanted to return it to polished bare hull. So they said if that's the goal, then thinners, stripper and & scraper is really the only way.

Or I get it wet grit blasted and DO put new antifoul on - but a fresh, single, coat of antifoul will look a lot smarter than the tripe that's on there at the moment.

Decision decisions.

[Pikey Dave]

Originally Posted by Matt

So I had a chat with the guys at the yard yesterday about removing antifoul.

They said even the mildest wet grit blasting will need quite a bit of repairing and making good if I wanted to return it to polished bare hull. So they said if that's the goal, then thinners, stripper and & scraper is really the only way.

Or I get it wet grit blasted and DO put new antifoul on - but a fresh, single, coat of antifoul will look a lot smarter than the tripe that's on there at the moment.

Decision decisions.

I’ve heard good things about Coppercoat AF, it’s a fit & forget job afaik.

[Matt]

Nasty colour though. I probably don't need antifoul at all - I will dry berth the boat - but I just need something on the hull so it looks smart and I get a couple of knots back.

[Pikey Dave]

Originally Posted by Matt

Nasty colour though. I probably don't need antifoul at all - I will dry berth the boat - but I just need something on the hull so it looks smart and I get a couple of knots back.

You could just paint the hull with non-antifoul in the colour of your choice. Nugent has done some cracking hull paint jobs with a 2pack paint system.

[mick]

I used the thinners and scraper method and then had it sprayed, it will depend how they keyed the hull for the anti foul to bond.

[Orwell boy]

Originally Posted by Orwell boy

Follow this advice above and you will be happy ,i have done this 3 hulls over the years and it just comes down to what the prep was like before the first coat of antifoul .i had a sports boat that had been done with an 80 grit angle grinder ,but retrieved it going thru the various grit papers ,but had a barn then so spent a whole winter on it ...................but this is the info you must not ignore !! the makers of CT1 make a safe stripper called peel tec ,it is brilliant on antifoul ,i bought six cans for a 6.5m hull and had two left (12/14 £ a can wickes i think ), some just seem to paint the hull over the gell coat which makes it easy if your lucky ......either way go and buy a aerosol of peel tec ,go sparingly and you may be shocked ,what i found is some types of antifoul comes off a treat with BK,s thinners and the peeltec gets what wont shift
good luck

Pm me your address and i will send you a can of the peel tec i had left foc,why do people ask for advice on this site and then take no notice of the answers they get ,surely its not the £14 !

[gtflash]

I had a rib with flaking anti foul. I tried chemical removers and didn’t really win. The paint scraper caused damage. Admittedly this was 2 decades ago.

My current rib has copper coat and I hated the colour originally but now I don’t care. She was going to spend 3 seasons in marina but only did one so it never greened up enough.

My research concluded anything greater than 600grit is a waste of time, even on fast boats like we have. My whole copper coat is burnished to 600 grit now.

No idea if it changes things but she still runs similar 65-71mph ….

[Matt]

'Flash : Yeah, I agree with your observations re surface finish. Sharp corners on the rails & transom are worth having, but the overall finish - 600ish is about spot on for performance. The idea "in theory" being to get a nice stable boundary layer. In quotes, since, in my view, once you're running fairly quickly, the surface of the water is so turbulent & aerated anyway, that any smoother won't add any benefit. So as long as it's "not too rough", it'll be fine. And when I upgrade to a yacht, I think coppercoat will be the way to go.

Orwell boy - Re Peeltec - were you having a pop a me? I've read everyone's reply on this thread, esp yours. But in addition, I happened to be chatting to the guy who does the shotblasting at the yard. Anyway, I found that just thinners (since I had some in the garage) is not effective - and then it started pissing with rain. I'll "deploy" the peeltec next time I'm there. I read and appreciated your input and will be trying it.

[beamishken]

Originally Posted by Matt

'Flash : Yeah, I agree with your observations re surface finish. Sharp corners on the rails & transom are worth having, but the overall finish - 600ish is about spot on for performance. The idea "in theory" being to get a nice stable boundary layer. In quotes, since, in my view, once you're running fairly quickly, the surface of the water is so turbulent & aerated anyway, that any smoother won't add any benefit. So as long as it's "not too rough", it'll be fine. And when I upgrade to a yacht, I think coppercoat will be the way to go.

Orwell boy - Re Peeltec - were you having a pop a me? I've read everyone's reply on this thread, esp yours. But in addition, I happened to be chatting to the guy who does the shotblasting at the yard. Anyway, I found that just thinners (since I had some in the garage) is not effective - and then it started pissing with rain. I'll "deploy" the peeltec next time I'm there. I read and appreciated your input and will be trying it.

When you tried the thinners did you have the rag saturated with thinners? I soak a fairly small rag to the point the thinners is almost dripping off & hold it on the area for a while to soften it then start rubbing, once you have a soft edge you can work into it. It doesnt work if the cloth is just damp, it needs to be wetting the surface to melt the antifoul. You can soften most single pack paints this way