Flow Aid

Flow aid, also known as flow improver, is an additive which when used as a medium thins paint slightly differently than water. With straight water the pigment tends to sink, whereas flow aid suspends it closer to the surface.

When mixing a wash, we want the color to sink, but for straight painting we want the colors to cover evenly. Flow aid also messes with the surface tension of the paint, making it flow off of the brush easier.

There are plenty of companies that will happily sell you little dropper bottles of flow aid, and that is fine. However this is another one of those cases where a few extra dollars at the local art supply super store will stock you up for many years.

The flow aid you buy at the art store will be a concentrate. However, it is easy to mix. The brand I buy recommends a mix of twenty parts water to one part flow aid. So I mix up a big batch in a squeeze bottle, and use that to refill a dropper bottle I got from Reaper. I mix it using our digital kitchen scale, adding 300 grams of water to the squeeze bottle and then 15 grams of flow aid.

I paid $8 for the bottle of concentrate from the art store. It will refill my big squeeze bottle 7.5 times, or my dropper bottle 155 times. In contrast, I paid $3 for the bottle of premixed flow aid from Reaper.

Now, if you aren't using flow aid, and you are happy with your results, don't worry about it. However if you are noticing problems getting even coverage, give it a try. It might do the trick.

This post was adapted from an article originally published on the Mad Adventurer's Society.