colin window cleaner as a thinner

Looks to me like the main ingredient in Colin is vinegar. Windex is a completely different formula with ammonia. So, I doubt you would get the same effects. In fact, I don't know how vinegar would react with acrylic. I doubt I'd try that unless I was desperate.

Ditto on what BD said above.  If you know anyone that uses any kind of window cleaner with ammonia, borrow a small amount and try it on an old scrap of plastic. That way, nothing ventured and nothing lost except a little time and a couple drops of paint. Try a small amount, paint the scrap, and let it dry overnight to see if anything happens in the drying process. Be sure to let us know the results as someone else might have the same question.

Hope that this helps.

Jim 

Test it on a scrap with the paint that you want to thin.

The only vinegar I have ever used on my bench, is distilled white vinegar, as a cheap substitute for decal setting solutions.  I have never tried using it as a paint thinner.  For acrylics, I use either water or isopropyl.  So I'm curious, too, to know how it comes out for you.

Stay away from using ammonia in your airbrush. Its caustic to the brass and other plating.

Ammonia is nasty stuff.

Colin failed. Broke the paint away. I used isopropyl alcohol instead. Worked like a charm.

Window cleaners with isopropyl alcohol will work.  But iso is usually also available in drug stores or other stores that sell medical products.

My thinner of choice for acrylics. Either 70% or 90% work fine