Antifoul stripper, which one is best for realy old antifouling

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hanjae

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My fibreglass hull was anti fouled in 2000 but she was not put in the water but is going in this year. I want to use an antifoul paintstripper and wondered what your impressions were and recomendations!

There is no delamination or osmosis on her.

Cheers
 
I found that the one that really worked best had a steel blade and two handles.

Seriously, Interstrip (more expensive than a lot of antifoulings) is ok for removing 3 or 4 layers, but needs several applications for serious build up. I suspect Dilunet is similar, and as you're probably aware there are other even more expensive options out there that make great claims. If you google for ybw.com and antifouling stripper then you may find some interesting data from here that I forgot to bookmark.
The easiest way to remove it by far is to get the yard to blast it off. Costs £500-£800 for a 25-30 footer, IIRC.
 
If you blast off the old antifouling with grit it will expose voids in the gel coat and the recommendation is then to epoxy the hull to make it watertight again. Failing to do this is likely to lead to future problems. This can all work out quite expensive

I have been through this recently and found that using a scraper was horrible and very long and hard work, a Wickes professional scraper (like a Scarsten scraper - but no longer available) worked best but it got through a lot of blades and I found it really easy to dig into the gel coat, so some epoxy filling will be required even if you do scrape the whole hull off.

For stripping I can recommend from experience making up a strong caustic soda solution (add a few hundred grams of caustic soda to a couple of litres of water - never the other way around. Expect the solution to get very hot and fume, so do it outside) When its cool, add wallpaper paste to thicken it to a gel like consistency and then paint it liberally on the antifoul. Cover the surface with cling film to stop it drying and leave it as long as you are able to. This will soften the old antifoul so it can be scraped off quite easily. It may take several applications, but it does work well and caustic soda is cheap so its not an expensive business to go this route

Caustic Soda is quite nasty stuff and will burn you if you get it on the skin, so wear suitable protective clothes and eye protection and be sure to wash off well if you get it on you.
 
Not entirely sure of your situation, but if you're saying that the boat was antifouled in 2000 but hasn't yet been in the water, why would you want to strip the antifouling at all? Presumably it's a fairly smooth and sound surface. Why not just apply new antifoul on top and then launch it? Removing antifouling is a messy business - avoid it if you can.
 
I found Interstrip worse than useless. I had many layers of up to 20 year-old antifoul to strip and found a series of 1/2" to 1" chisels were the only real remedy.
Very crap job.
 
Bahco Scrapers are the bestTCT tipped blade double sided. used one on my 45ft cat to take of 8yrs of AF build up. Mix Caustic soda in Wall Paper paste CAREFULLY and roll on CAREFULLY All very effective but a lousy way to spend a day.
 
It is easy to stand back at the marina and fret if the underwater hull is less than shiny and even. Keeping it this way is nigh impossible as antiufoul erodes unevenly and flakes when exposed all winter long. I weigh in my mind the damage that can be impacted on the hull by bashing away at the antifoul to achieve a smoothness that for cruising purposes is just cosmetic.

I have scraped a hull back to gellcoat and hard work it was - but with patience, scraping is the only cheap and relatively safe way - for you and the hull. I used a Skarsten Scraper and rounded the blade's edges to prevent digging in when the blade turned. I mounted the scraper on a 3 foot handle to give greater leverage and speed on the job.

I did that once - there are not many members of the twice- scraped-a-hull club!

Looking around my yard, I fear that too many folks throw too much paint on and compound the problem of build up for themselves!

PWG
 
I would do no more than put on some fresh antifoul & launch - unless there's a bad build-up or you want to remove it all for coppercoating or something...
 
As others have said, unless your antifoul is seriously thick and flakey, I wouldn't bother. It's going to be hard work or expensive. Even if you're racing, unless you have a team to do it all for you, you aren't competing at a level where a slight unevenness of the hull will matter.

If you really must, when I did mine. I used a Bosch PSE180E, which doesn't seem to be available any more, but a google will point you in the right direction for an equivalent. It was just as exhausting and messy as using a hand scraper, but got it done a lot faster, at the cost of a good few digs in the gelcoat. (round off the corners of the blade and you'll reduce the number and depth of the digs, but probably not eliminate them entirely.
 
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