Charles,
For the airbrush what size tip/needle have you used for shading? The Paasche VL airbrush that I have comes with a No. 3 needle and tip, their manual indicates this gives a medium line weight. They also offer a No. 1 needle and tip for a fine line and a No. 5 for a heavy line. What is a good size for our purpose of canopy shading? Do you use a compressor or for these small parts is the canned propellent good enough?
For the paint, they show acrylic that is thinned with a mix of distilled water, ISO 90% rubbing alcohol and a bit of glycerin. Seems this is like base coat which also can be wiped off is rubbing alcohol. So clear coat topcoat should protect the shading.
I have seen videos of shading where they use a 50/50 mix of thinner/paint. is this what we should use or 60/40? One tip they showed was using a gravity cup (1/4 oz.), they put the thinner in first then the paint and mix it in the cup with a small brush. They said this insures that you don't get a blob of unthinned paint being spurted out on the work.
Best, DennisT