Can I put 'thinners' in antifoul paint?

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NPMR

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My antifoul paint is very 'thick' and will be quite hard to put on evenly.

If I 'thin' it to make it easier to apply, will this affect its performance?
 
Heck, yes! It's practically impossible to use without thinning. Be sure to use the correct thinners. Stir thoroughly, and stir repeatedly during application. In warmer weather, the thinners can evaporate quite quickly, so the paint in the tin can get thicker. Remember that for best performance you have to apply the correct quantity of antifoul (manufacturers recommendations). This is an important consideration if you're thinning it, as you will probably have to do more coats in order to use the proper amount.
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It is fairly thick but it can be thinned if necessary but remember it is usually intended to be applied fairly thickly so do not thin more than absolutely necessary

Keep the contents of the tin well stirred as it tends to settle fairly quickly.

I would suggest that you use the thinners recommended by the manufacturer although I believe some can be thinned with white spirit.

See the manufacturers product data sheet for all the info regarding rate of coverage , film thickness etc. You may find it advises not to thin!
 
Absolutely fine to thin it otherwise its like spreading porridge. Its efficacy wont be affected as long as you keep the thinners to a minimum needed to keep it spreadable.
 
I always apply as it comes, it seems to go on alright on a warm day. Like someone said above stir,stir and stir again and keep the lid on the tin in between refilling your paint tray. This keeps flies/dust out and stops the solvents evaporating.
If you must thin it, refer to the instructions on the tin or online.
 
JumbleDuck said:
The only times I have need to thin have been when I haven't stirred it enough on the first place and got down to a layer of porridge.[/QUOTE
I have just applied two coats of antifouling. First tin took about 20 mins stirring with a flat stick,second tin was like non-drip emulsion thick as jelly. Wrist breaking stirring is the only answer.
Once poured/glooped into a tray and rolled onto hull it becomes thin enough to spread out. 2 1/2 litres per thick coat on 23ft bilge keeler.
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Easy KTL solution to thick anti-foul

boil kettle, make a cup of tea, place remainder of boiling water in a bucket

place the can of paint in the bucket

drink tea

then start work

warm paint spreads much easier and no compromising on efficacy

try it lads

it works

D
 
+1 on the hot water trick.
I never tried that with antifoul, but spraying a car repair with cans its best to float the cans in a bucket of hot water and shake them in turn. The spray is more even and it dries quicker.
 
pvb said:
Heck, yes! It's practically impossible to use without thinning. Be sure to use the correct thinners. Stir thoroughly, and stir repeatedly during application. In warmer weather, the thinners can evaporate quite quickly, so the paint in the tin can get thicker. Remember that for best performance you have to apply the correct quantity of antifoul (manufacturers recommendations). This is an important consideration if you're thinning it, as you will probably have to do more coats in order to use the proper amount.
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+1 - I always thin it, couldn't get 2.5 litres to cover a 35 ft hull without doing so. The makers would like me to use twice or triple the amount, but one 2.5 L of Shogun seems to work well enough for April-November in Falmouth and I don't get a thick build-up.
 
Seashoreman said:
Dylan you are becoming a guru, do you know that? If I may add, oh master, stirring with a thin one inch flat stick also helps.
Unless you can find a way to strap the can down, be very careful with power mixers.
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for 2.5/3 litres, get a bigger can eg at least 5litre oil can. cut the top off to allow it to be cleaned out. pour the bulk in and power mix, then decant some back to the original can to loosen up the remains.

Then you'll have the space to add thinners if you want to.
I use 20litre cans as I have a ready supply of them from work.

They are also handy to cut the corner off and use as toolboxes....eg for electric sander, sheets, rubbing block etc.
 
jwilson said:
+1 - I always thin it, couldn't get 2.5 litres to cover a 35 ft hull without doing so. The makers would like me to use twice or triple the amount, but one 2.5 L of Shogun seems to work well enough for April-November in Falmouth and I don't get a thick build-up.
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You're lucky to get one thinned coat to provide adequate protection. Two coats and three round the water line of full strength seemed to be needed in the waters of the Tamar some years.

To the OP. I don't believe that white spirit is the correct thinners for any a/f on the market in the UK. Use what the manufacturer suggests would be the best advice. A/F seems to have some fairly volatile thinning agent in it from my experience.
 
chewi said:
for 2.5/3 litres, get a bigger can eg at least 5litre oil can. cut the top off to allow it to be cleaned out. pour the bulk in and power mix, then decant some back to the original can to loosen up the remains.
Click to expand...

I use a cheap black 2 gallon builders' bucket. Pour, scoop and chisel contents of antifouling tin into bucket, stir well, paint from that. Luckily I know that 2.5l gives me perfect coverage and 3l allows a wee bit more round the edges, so one can is just right.
 
I thin gaelforces best with white spirit- no problem whatsoever and nothing seems to go anywhere near it!
 
No - according to some manufacturers, you should NOT thin antifouling paint.

"Antifouling paint performance in general terms is dependent upon the film thickness applied at application time. Interlux antifoulings are formulated to the optimum viscosity, or thickness, for their designed application thickness. Thinning can significantly affect the application properties of an antifouling. "

Source
https://www.interlux.com/en/us/support/boat-painting-tips/thinning-antifouling-paint
 
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