Acrylic thinner

In many of the modelling articles and discussion groups I've read, Americans have extolled the wonders of Windex Blue as a thinner for acrylic paints. I've never been able to find Windex here in New Zealand, but what I have found is this: ArmorAll Windscreen Wash. I've tried it with Vallejo ModelColor acrylics, and it works a treat.

It, like Windex, has ammonia in it, plus (I assume) a bunch of surfactants and detergents and what-have-you. The ammonia helps thin the paint without granulating or blobbing, and the surfactants act to lower the surface tension, working like an acrylic flow-enhancer. You need to use very little to get the paint flowing nicely, much less than you would need plain water, which is advantageous as it means the pigments are less diluted and there is less loss of opacity.

I've found it works best as a thinner for airbrushing. It works very well with brushing as well, but it does have a tendency to create lots of tiny bubbles if you get too vigorous with your brush action, especially if you've over-thinned the paint (as I did the first few times I used it). The bubbles do usually dissipate as the paint dries, but it's not guaranteed, so it's best not to take the risk.

At my current rate of use, this bottle should last me until about 2050. I myself will think myself lucky if I last until 2030.

Note: If you use technical pens or dip pens with indian ink, this stuff should work well as a cleaner for them, though I admit I haven't actually tried it yet. Indian ink cleans up pretty well with ammonia-based cleaners.


  1. I purchased some Future, which is supposed to be another good one.

  2. I wouldn't use Future straight as a thinner, though it does work well to reduce surface tension when used about 1:4 to 1:5 with water.