Thinner

Try some high-quality mineral spirits as they work very well and I think that is all the Model Master airbrush thinner is.
I don't like lacquer thinner with enamels as it dries too fast.

Mike

When I use enamels, I use a very inexpensive and somewhat new product called T.R.P.S. or (terpentine replacement paint solvent) It is an excellent replacement for MM Airbrush Thinner. It seems to blend the paints' vehicle and solvent far more thouroghly than MM or other regular mineral spirits. Thanks to it's high solvent power and proper evaporation rate, this helps prevent premature drying, and helps provide uniform film thickness and paint adhesion. It acts as if it has a flow agent in it, so as to maximize paint flow through the airbrush. It's available at most home improvement, and Sherman Williams-type stores. It goes for about $3.00 in my area. It is manufactuered by *Sunnyside, packaged in a white, yellow and blue 1 QT. can. T.R.P.S. is also a very good cleaning solvent for your airbrush as well, reducing the use of Laquer thinner in most cases. Give it a try, it's all I use for Model Master enamels.