Testor Corp. MM 1/2oz Pearl Purple For airbrushing use 1789, 8824 or 8825A Enamel Airbrushing Thinner Use the following ratio as a starting point Gloss: 3 parts paint to 2 parts thinner Flat: 3 parts paint to 1 part thinner Compressor regulator setting: 16-25 PSI Enamels require 48 hours to completely cure.