I've been happily using Vallejos Model Color paints for a few years now. In the past I've used the milky white thinner with MC, and had very good results - the main issue was the tip of my airbrush would dry, and need to frequently be cleaned. I've read that the tip dry issue is less  pronounced with the new clear thinner.

Until this morning I've never tried the newer clear Vallejo airbrush thinner with Model Color - and thought I would give it a go.

Turned out to be a complete horror show; paint runs, dry spatter, paint coverage issues, flow and then airbrush upchuck. The dry spatter was by far the worst symptom.

I did try it with two colours (medium grey, and sand); I thought the issues might have been pigment related. I tried a variety of paint to thinner ratios (started at 1:2, ended up at 1:4). At the lower ratio (1:2) I ran more pressure, maybe 25 psi - at the higher ratio (1:4) I was running about 15 psi. Each time I mixed the paint and thinner together by first dropping the thinner in the airbrush cup, then the paint, Finally I used a back flush of air to mix the thinner and the paint for 45 seconds(isn).

I believe I'm doing something wrong here, but I'm not sure what. I can salvage the model with some gentle, gentle spot sanding, and reverting back to my old stand by milky white thinner. As I think it's an operator error, I'm looking for comments, feed back and advice.

Any help would be greatly appreciated.

Jason