Spraying Pearl Ex Powder
To spray mica powders in an acrylic medium, you start out just like the way I discussed in a previous post published last August “Making Your Own Paint From Mica Pigment”. You start with a dry mica pigment powder in a container. You then carefully add just enough water to wet the fine particles and create a “slurry“. Once it looks homogenous, you add copious amounts of acrylic medium. The “slurry step” is used when mixing mica powders with other mediums as well. In the case for oils and alkyds, you would wet the pigment with mineral spirits,naphtha, or enamel reducer. For lacquers you would use lacquer thinner. More on this later.
The two photos show the dry pigment on the left and the slurry on the right. You stir but not so fast to generate too many bubbles. If the powder is not cooperating with the water you may have to add a few drops of alcohol. Some artist paint manufacturers have a product that is specifically designed for wetting pigments. It is a blend of surfactants.
Add the Acrylic Medium
Once you have made sure all your pigment is fully wetted and suspended, then you can add your acrylic medium. You want to add quite a bit. The Pearl Ex pigment featured in this post is typically used in 10 to 12 percent ratio to the medium. This allows for the pigment particles to spread out in the drying medium and reflect the most light possible creating the shimmering affect.
After adding the medium and blending it all together, the mixture may lose its shine. This is normal due to the opaque nature of the uncured acrylic resin in the medium. It will dry clear after time to allow for the shimmer effect.
It also bears mentioning that if you thin the acrylic mixture with water it needs to be maintained at a decent viscosity or the pigment might separate. If you are airbrushing when this happens, it could lead to painting disaster. Look at the photo below showing mica pigment that is a medium that has been watered down too much.
The Alchemy of Making Airbrush Paint
With my Badger 250 airbrush, I typically use a large tip and a pressure of at least 40 psi. The mix that usually works for me is one that is noticably viscous but does not leave a “trace” on the surface while pouring it into itself. I would describe the consistency at heavy cream. You will have to experiment for yourself. Get plenty of scrap material to practice on.
Importance of a Basecoat
If you apply a basecoat to tone the mica coating, a light dusting is all that is necesssary. Look at the pearlescent magenta finish above. It is a beautiful thing nearly impossible to properly photograph.