Removing paint.

[Noboat1]

Good afternoon. The antifoul waterline on my boat has, over the years with various owners, crept up and up until now it's about 6 inches too high. Can anyone advise the best paint remover to use that will not damage the gelcoat underneath as I'd like to get it back to a nice clean white? Many thanks.

 

[V1701]

You could maybe use the likes of a bahco scraper (the one with the ball on works best), with the very ends of the blade filed down to prevent gouging of the gelcoat, to remove the bulk of the excess. Then scrub the remainder off but you're going to do well to make a nice job of it and it's hard work. You're not supposed to use the likes of electric sanders with antifoul. AFAIK there are gels on the market that are supposed to help with antifoul removal but I haven't tried any, others may have...

 

[PCUK]

I wouldn't use a scraper on gelcoat that needs to be shiny. Google "Antifouling remover" and you will have a wide choice of products that won't damage the gelcoat.

 

[Slowboat35]

No chemical can do that. Anything that will strip antifoul will wreck gelcoat too.
I think only physical removal will work, and that means laborious and painstaking scraping.
Suggest a Linbide scraper (by far the best tool) and lots of careful work.
Gelcoat left shiny? Seriously???
Oh dear!
It'll very likely be scored and scraped to hell if the antifoul was applied properly in the first place. Good luck.
Sorry.

ps. Bahco scraper looks much the same.

 

[chris-s]

There are plenty of modern antifoul strippers that will safely remove the stuff without damaging the gel coat.

Depending on how thick it is you might want to remove some of it with a scraper or something first. We happily used an orbital sander with a vacuum attachment to remove the bulk being careful not to break thru the bottom layer and sand the gelcoat, tho where we did slip up, it was easy to make good.

Don’t let the antifoul stripper dry out, you need to cover it with something like the thin lightweight polythene painting and decorating dust coverings so it stays wet and gets time to soak thru and work. You might need multiple applications.

Once the stripper has done its work you will still likely need to clean up some remnants, white spirits and paper towels do a good job.
We removed a four inch strip from our boat where it had been previously raised by a previous owner.

Fortunately there weren’t too many layers and the exposed gel coat polished up as good as the rest of the boat.

 

[William_H]

I would strongly recommend the OP leave water line too high or if he is really determined try just reducing it a little. A/f paints seem to be very imune to paint stripper chemicals like caustic soda. Perhaps others might work. Just get out and sail. ol'will

 

[Refueler]

You're not supposed to use the likes of electric sanders with antifoul.

Very interested in that comment ..... nearly every yard I know - if not using blasting - use electric sanders with vacuum attachment .....

 

[Noboat1]

Well, quite the mixed bag there!! Thank you all very much - plenty for me to think about. Clearly an attempt out of sight below the waterline as an experiment would be a good start - just in case. Then decide where to go from there. Thanks for the suggestions of tools, I'll check them out. Much appreciated all.

 

[KREW2]

What about putting on a boot top.

 

[V1701]

Very interested in that comment ..... nearly every yard I know - if not using blasting - use electric sanders with vacuum attachment .....

Soz should have said probably ok if hooked up to vacuum and sanding by hand should be wet. I wonder if there are any places where they'd not be happy with sanding at all, in which case what would you do? Fortunately the PO of my boat put on Coppercoat...

 

[Noboat1]

What about putting on a boot top.

Thank you. That's my 'Plan B' if I can't remove the paint. I'd do it the same colour as the rest of the hull (white).

 

[Daydream believer]

What about putting on a boot top.

You could do one in 2 colours to give it a more "racy" look once you have sanded back the old paint to the original surface

 

[Noboat1]

You could do one in 2 colours to give it a more "racy" look once you have sanded back the old paint to the original surface

A nice thought but I'm not sure a Golden Hind has ever looked 'racy'!! Thanks though.

 

[Tranona]

Photo of my GH. You can just make out the white 50mm wide boot top. Personally I would not try to remove old AF and expect to get back to shiny gel coat. Hard work whatever method you use and no guarantee of success.

 

[lusitano]

I,ve used this a few times and had good results although it needs to be applied a few times if there are lots of coats
to remove.
Zero damage to gelcoat.

Peelaway Marine Anti-Foul Removal | Peel Away

 

[Refueler]

Hull strip and checks - Conqubin 38CR

Yard is electric sanding back -removing old A/F to make good for new ...

 

[PabloPicasso]

I scrapwd the complete underside removing years of crater like AF. I used a jetwasher to blast of the aorst of the flakey stuff, and a pull scrpaer and dibbling running hose to prevent dost, and keep the AF soft/damp.

It was tough going, but did a couple of hours at a time on my day off and on the weekends. Got the lot off over a couple of weeks. Its all much much better now.

 

[Refueler]

Many years ago - I had an Alacrity 19 - that previous owners had basically recoated topsides repeatedly ... it must have had about 2 - 3mm of paint layered ....
After a 'scrape' - we all have such moments !! I had a patch on the port transom where the paint had been removed showing the depth of it. I had a decision to make - try remove the built up layers or try patch in the area about the size of my hand on the transom ... note - the depth was enough to consider filler and then topcoat colour !

I made decision to remove all topcoat paint .. a decision that I regretted once started. It was terrible work - I tried chemical stripper ... hand scrapers ... in the end electric sander ... but the sander was so slow that I made a big error of changing to a disc sander ... Yep - I admit I did it ...
Now the paint was coming away at a reasonable rate ... but OH DEAR ... when you looked along the hull - it was dips and peaks .. no longer a level smooth surface.
I could have used Fine Fill (Internationals finishing filler) and then board sanded her back ... but decided to just go with it ... I gave her a new topcoat and sailed her for a few more years and sold her on. I was honest with buyer about the hull.

I was young .. eager to get the job done ... ignored my own advice !!

So please anyone thinking to sand - do not use a disc sander ...

 

[Daydream believer]

I wanted to remove my antifoul paint (I think that it was around 2005) ready for coppercoat. It cost me £200 cash & I stood & watch the guy sand blast it very carefully. He did leave some patches of antifoul because he did not want to damage the gel. That took me about 4 hours sanding to remove. I then took a couple of days removing a 50mm strip at the waterline that he left to avoid damage to the topsides. That was so thick that some of it & chipped off with a sharp chisel.
When finished the hull looked like a sheet of A4 paper. It was well worth the 200 sobs & all done in a week

 

[Noboat1]

Photo of my GH. You can just make out the white 50mm wide boot top. Personally I would not try to remove old AF and expect to get back to shiny gel coat. Hard work whatever method you use and no guarantee of success.View attachment 175459

I'm not sure I can make it out as it's a lovely job. She looks perfect. That may well be the answer. Thank you.