Can I put 'thinners' in antifoul paint?

[Binnacle]

And according to some other manufacturers, one CAN thin AF with e.g. Thinners No 3. Other numbers may be needed for different base formulae.

antifouling thinner - Search (bing.com)

 

[thinwater]

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
Can I thin antifouling paint?

Not wrong. But not entirely correct either, or rather incomplete. It does NOT take into account that the viscosity changes with temperature, and that cool weather may require some thinning to be equivalent to hot weather application. So it is IMPOSSIBLE for one formula to be correct for all weather conditions and they know it.

The answer is that you want to get X amount of paint on the boat. If you thin it too much you may need one more coat. A smarter way of putting this is "this paint must be applied at x gallons per 100 square feet to give 2-year anti-fouling protection."

As for the solvent, the simplest rule of thumb is to read the SDS and use something similar. Don't guess. None of them use acetone. Most don't use mineral spirits. For most solvent based paints, xylene is the closer match, but check. I know many of you get an ice cream headache at the thought of ... chemistry.
Sample Interlux SDS

 

[vyv_cox]

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

He has probably done it by now, as the thread is nine years old.

 

[Graham376]

For most solvent based paints, xylene is the closer match, but check. I know many of you get an ice cream headache at the thought of ... chemistry.
Sample Interlux SDS

For Jotun Seaforce, I've found synthetic thinners or Xylene work well.

 

[Scomber]

Just thinned it today , as ive prob done for last 9 yrs of this thread, ( ah no 8 yrs, missed a covid yr). Was a lovely day on w coast but a bit chilly. Antifoul was a bit like porridge to begin with. Had the real porridge after job was done. Never that bad fouling up here anyway.

 

[vyv_cox]

I have come across many keen racers who apply one coat of thinned antifouling just before a race, then remove it afterwards.