Practice Spray Liquid...

[Derek Arita]

I'd like to do some practice spraying with water, but I know that many of the finishes are not the consistency of water and will spray differently. For instance, the waterbourne poly that I plan on using is a lot thicker than water. Is there any kind of thickening I can add to the water or maybe something else I can use for practice?

[Scott Holmes]

Practice spraying the water evenly on cardboard. Once you have that down, then practice with the finish. A few cups of finish should do it.

[Rich Engelhardt]

Add some flour to the water to body it up.
Toss a bit (maybe a tbl spoon to the gallon) of Lysol in also so the flour/water mix doesn't sour and stink the place up.
If you want to simulate paint, a few drops of food color does a good job.
Green and/or blue seem to work the best.

Way back when, we used to use flour based vinyl wallpaper paste (Sanitas) since it already has a mildew agent added.