Removing Antifoul Wet or Dry how Toxic is it?

[tonyrush]

My boat has many layers of antifoul which I want to remove back to the gel to apply coppercoat .
Does anyone know how toxic it is to sand off? even wet sanding how toxic is it to you and how can it effect you?
I have read how infective the antifoul removal potions can be and they are expensive to buy.
So before I start with a DA sander dry or a bucket of water and a sanding block wet.
How damaged can I get?
many thanks
tony

 

[VicS]

It should definitely not be sanded dry due to its toxic nature.

Sanding off many layers will be an impossible task and the use of a power sander is likely to damage the gel coat if you ever reach it.

Chemical strippers ugh!

Professional soda blasting expensive.

Mines got 30 years worth of AF on the bottom and I do not anticipate either trying to get it off myself or paying to have it professionally stripped!

 

[William_H]

this question is a fairly common theme for this forum. I think many recomend a stripping tool/ machine by Sandvik but I have never actually seen one. The problem with using Vics approach is that eventually starts to come of in pieces to leave a very rough surface.

My approach has been Caustic soda (cheap) but dangerous.

I am not sure just how dangerous the stuff is when dry sanded. i am not prepared to say don't worry. The professionals do it in purpose built facilities with full air supply face gear. And perhaps if you can afford it the best way might be to pay a specialist to do it.

My own approach is somewhat unusual in that I wet sand it while in the water. But I put the bare minimum on each spring and do a lot of in water huill wiping so that it is pretty thin by end of summer.
olewill

 

[Impaler]

I've used an anti fouling stripper, high pressure washer, face mask with filter not a dust mask and goggles.

 

[Pasarell]

Dry sanding is very dangerous both to you and anyone else in the vicinity.
Wet sanding, as already said, is long and laborious - certainly not for the faint hearted. You also need good protective gear as it's not a good idea to get the wet residue running down arms etc.
Chemical strippers work but it is slow, messy and laborious if you have a number of coats to remove.
Eventually you will have to take old A/F off if you don't want a very patchy bottom! Every time you apply a new coat you are hanging it off the bond between the first coat and your hull. That will get tired and fail sometime.
Slurry or soda blasting has to be the best way in my opinion. Slurry blasters on the south coast charge £13 - 15 /ft loa. Soda blasters usually a little more.

 

[ex-Gladys]

I've done it twice. On Amber and Gladys... Both times I used Dilunett which is a Caustic soda based product and was less than half the price of other strippers. I also tried mixing my own but couldn't get it strong enough (caustic and wallpaper paste).

Do it when the weather sin't too cold, otherwise the caustic solidifies out in the contaiiner, and temperature helps the activity. Make sure you have really well thought out PPE, because that stuff hurts like hell. e.g. make sure you get thick domestic rubber gloves and tape your sleeves into them.

I removed three coats on Amber and about 9-10 on Gladys. The latter took a couple of applications of jollop

 

[lw395]

Depends on the antifoul, but sometimes scraping with a chisel is surprisingly quick, and produces flakes not (so much) dust.
This works best when the AF has really dried out, ie after months ashore. If you get to it within hours of lifting, a lot more comes off with a scouring pad.
I still wear a mask and stand upwind though.
I now tend to use VC offshore, which responds to use of a wet and dry sponge block.
I don't think the dust even has to be toxic to do damage, take care!
Chris

 

[NealB]

Excellent question!!

I've often asked this question, and the answer is, "don't do it, it's very toxic, very dangerous".

Worrying, to say the least.

But what are the dangers? Headache and sore throat for a day or two? Asthma? Cancer?

What research has been done?

Does anyone know?

 

[DJE]

When the AF on mine got so thick that it was coming off in flakes I scraped it all off with a conventional straight wallpaper-type scraper. But I shopped around for the stiffest blade I could find and kept it sharp with a fine file. It came off surprisingly easily but I still spread the job over three winters and this year I'm looking forward to my first winter without scraping. I wore a dust mask while scraping, collected the flakes on old dust sheets, and put them in the bin.

 

[pmyatt]

Some years ago I used Interstrip to get about 8 coats of antifoul off a 30 ft hull - in the UK in February. Action was slow but sure - will use Interstrip again if I ever do the job again (different boat now).

 

[Dipper]

I have tried various methods in the past with limited success.

Following advice on these forums, I stripped my antifouling last winter using one of those paint scrapers with an angled head attached to a handle. The Sandvik was recommended but it was very expensive so I bought a Hamilton from B&Q - I think it was under £10. This had replaceable 2" blades which were double sided so you could use the second side when the first one became blunt. It worked brilliantly!

The technique is to use it two handed. Hold the handle in one hand and press the angled head (with blade) onto the hull with the palm of the other hand so as to keep a steady pressure. Then, if you get the pressure and pull speed right, it just shreds all the paint layers off in one movement with a satisfying juddery noise. I stripped a 26ft yacht in about 2½ hours per side (excluding the keel). Another club member was using the old style paint stripper tool and taking days on a 23 footer so I lent him mine which finished the job off in double quick time! I had bought a spare blade but didn't really need it. To avoid the corners of the blade digging into your gel coat, round them off with a file/grinder before you start.

Wear a mask although it is more flakey than dusty. I caught all the flakes on dust sheets and disposed of them down at the local tip where they had a paint recycling facility.

 

[VicS]

[ QUOTE ]
Do it when the weather sin't too cold, otherwise the caustic solidifies out in the contaiiner, and temperature helps the activity. Make sure you have really well thought out PPE, because that stuff hurts like hell. e.g. make sure you get thick domestic rubber gloves and tape your sleeves into them.


[/ QUOTE ]
A couple of comments to make.
If using caustic soda based concoctions protect your eyes above all else. Caustic soda burns of the skin are painful but in the eyes it is excruciating so. You cannot open your eyes unaided to wash it out and permanent damage is very likely.

The the freezing or solidification temperature of caustic solutions follows a complex relationship with concentration. From memory, the freezing point initially falls below zero as the concentration of dilute solutions increases but then rises again to a maximum which is well above zero, falls again to a point which is still several degrees above zero and which IIRC corresponds to a concentration of 43%. It then rises again progressively to the melting point of pure caustic soda. A concentration of 43 % is therefore the best concentration to use as a compromise between solidification temperature and concentration. Sorry to be a bit vague and uncertain of the details but it is information I last referred to during a cold spell in the winter of 1975/6!

 

[lyina]

I did hear on the radio only a few months ago that an higher than average rate of Parkinsons was found in Farmers exposed to Pesticides and by Boaters who had removed Antifoul. No exposure figures were given,but no doubt further 'Googling' will reveal all . /forums/images/graemlins/frown.gif

 

[PeterGibbs]

Put it this way, why would you trade the slightest prospect of ingesting toxic substances for a smoother boat bottom? One that will flake again within 2-3 seasons...

One further thing - Is there anything more socially irresponsible in the boating world that the sight of an empty cradle with a pile of loose antifoul chippings just dumped for someone else to clean up?
Or a trail of windblown material onto someone else's patch?

We've all done it, there's no need for it and it's time to put a stop to it. Hopefully you will find a responsible solution to your situation.

Many thanks for reading this.

Peter GHibbs

 

[rob2]

I would recommend paying someone to slurry blast if you are looking to Coppercoat. It is the recommended route as it guarantees absolute cleanliness and a good, even key for the resin coating.

If you're determined to go the DIY route, then try and borrow the most powerful pressure washer you can and add a slurry blaster attachment. Feed it with kiln dried sand (B&Q on a Thursday are the cheapest) and ensure you keep the sand dry! Somewhere around a ton of sand should do a 30ft finkeeler. Believe me, you'll have so much protective kit on you needn't worry about toxicity. Wearing goggles and waterproofs, I still exfoliated my face! The results are slower than a professional rig will achieve, but just as effective. Just like the coating operation, you will need dry weather as only dust dry sand will flow up the venturi tube.

Good luck.

 

[Pasarell]

Re: Excellent question!!

I'm sure there are proper toxicological reports but don't know where.
Fine dust from sanding is not good to get into the lungs at the best of times.
Active parts of most antifoulings are cuprous oxide and organic biocides. For organic biocides read pesticides. Chemicals designed to kill things as sprayed onto fields by farmers to protect crops. The concentration in antifouling dust will be very high and lungs are designed to absorb what gets into them! Also getting the dust on skin, into eyes etc will all increase chances of problems.
I wouldn't scrape antifoulings with a chisel as that will produce a considerable amount of dust too.

 

[tonyrush]

Hi Thanks to ALL of you for replying
I like the Caustic Soda Idea I have some commercial caustic Gel which is not available to the public as far as I know very powerful stuff and much cheaper than antifoul remover about 35ukp for a 25Kg tub. If I survive I will let you know what happens.
If it ever stops raining that is..
many thanks
tony

 

[nedmin]

Dont forget that its just as dangerous wet as dry because the water vapour you are breathing in contains A/F.Going to do mine this winter by power washing a few times over a period using an airstream helmet.Re; previous post about Parkinsons, one of my friends retired at 57,he stripped his boat and was "blue coloured"every time I saw him, shortly after he got Parkinsons.At 57 thats young, makes you think.

 

[wotayottie]

How toxic? Not very judging from the growth on mine. And funnily enough I once asked my doc the same question, she checked with the poisons centre and they said it wasnt very dangerous. Obviously the answer varies from brand to brand and no one in their right mind sands off dry without a mask etc. So take all precautions but dont be frightened seems to be the message.

personally I would use a contractor because you need the hull to be squeeky clean for epoxy. I tried the Farrow system - brilliant result!

 

[catmandoo]

Read somewhere tht it diminishes your peanut size particularly when you look at description of other after effects