Airbrushing Tamiya Acrylics with my Paasche H - An Observation and a Question

Airbrushing paint is not an exact science. A higher air pressure, such as a siphon brush like the H needs, will let you spray "unthinned" paint. I'll presume the paint mixer mixed the paint thoroughly, but typically I would suspect the paint wasn't mixed enough.

Adding a bit of thinner will make the paint go further, so the cost of paint + thinner vs. more paint is an equation to consider!

Metallic paints are another thing altogether. I've sprayed Tamiya's X-11 Silver & XF-16 Aluminum with my Badger 150 and it's medium tip/needle without additional pressure, but I'm not sure if there is a similarity in needle size or just nomenclature. You'll have to try it and see. One thing you will need to do is make sure you thin properly and mix thoroughly and work fast, and keep the color cup swirling around a bit to keep the particles suspended. You may need more air, but I doubt it.

I have noticed that XF-1 is pretty thin to start with, but using Tamiya thinner in it Will allow thinner coats which still cover well - you are less likely to obliterate surface detail this way.

I have also shot Tamiya metallics without changing from my usual mid-size 0.2mm needle & normal pressure (15 >20 psi).

This is why there's no "correct" answer for the question "What is the correct thinning ratio for <insert brand name> paint?"

Even within a particular manufacturer's range, paint viscosity can vary from one colour to another, from one production batch to another and how long a particular jar/tin has been sitting on the shelf.

I don't thin paint to any set ratio, I don't even measure accurately, usually using the "Looks about right" method. As long as it goes through the airbrush cleanly, covers and adheres properly, that's about "right" enough for me.

In this particular instance, black is quite a "dense" colour and can achieve sufficient coverage even when applied very thinly. Provided you can get proper adhesion, Tamiya flat black can go a very long way.

Heed Bill's advice about spraying Tamiya metallics. The metallic particles in Tamiya's paints are quite coarse (though Gunze's appear coarser) and settle very quickly, so thin well, stir well, and work fast. I paint with a 0,35mm nozzle Sparmax gravity feed brush and sometimes have clogging issues with the metallics