My airbrush practice is now looking promising!

This is the Testors enamel/LT mix made famous by AndyX and DonnYost. This mix really does level out nicely and dries fast to the touch. No problems with dust at all in the paint station. The key is to get one or two light initial coats for tack then slow the brush down to lay it on heavier to fill out. Once the initial tack coat is established, it's virtually impossible to screw up unless one stops the brush altogether. I'm using the Gloss Grape, purple. When first sprayed on bare plastic, the pigment hardly shows at all. The color starts to develop and get richer with each and every pass. The color has to build up over repetitions. The red Testors that AndyX used in his video seemes to have a rich red color from the initial coat. Different colors may act differently. Painting the red cup was not ideal because purple has not much contrast against red so it's hard to see spots that were missed. I'm now sold on AndyX's video. Hopefully this same method can be used with Testors semi-gloss and flat paints as well. I will test each new paint on a spoon at first. I used no primer for my practice runs. The truck cab I used for interior painting practice was a damaged part that is ordered for replacement anyway. I now know how to attack hollow body interiors with the Paasche H. You can't use those uniform linear strokes as on a body exterior. What I did was hold the brush farther away from the part than normal and vigorously swept the brush side to side like a whisk broom as I moved the brush closer to lay a thin/mist coat down on one cab interior wall at a time. You have to hit the inside walls at about a 45-degree angle. You can hit the ceiling of the cab more directly. Then I spot shot the insides of the thin door and windshield posts and the cowling by pointing the brush at these parts to give one quick spray and sweep at a time. I worked around the interior of the cab carefully and repetiously to get the color and texture to build up to the desired level. It will not be feasible to try to get a cab interior as glossy and as glass-like as a body exterior. There is a lot of air current turbulance frrom the airbrush inside that tight enclosure. It is impossible to position the airbrush perpendicular to those inner surfaces for the most part. The paint mist swirls around everywhere inside there. The interior paint will have a texture that is somewhat like cloth and that is Ok for inside a cab and perhaps even underneath a semi truck hood though I'm sure I can get a glossier finish under the hood. The hood opens up to reveal the diesel engine. The cab interior is a dark low-visibility part of a vehicle model anyway once assembled. 

To prep my practice pieces, I took some Comet powder and made a paste with it using water. I took a toothbrush and throughly scrubbed the surfces to make them gritty. This is more ideal than sandpaper because sandpaper can wear away rivets in body panels. 

The compressor was set at 35 psi. 

Here is my video:

Here is the AndyX video that inspired me:

I use my 3M organic vapor filter respirator along even with my double-fan paint booth inside my apartment. Huge cloud of lacquer thinner vapor that momentarilly comes back at my face until the suction fans can take hold! That method works like magic, however. Paasche H Number 3 needle/cone/aircup set at 65% open with 35 psi on the DeWalt 1-gallon compressor.