\ said:
Cheers, I shall try again with no thinners. If it doesn't spray will apply small amounts until I get a result and see what happens.Cheers (yet again!) all
There are several factors to get right (for me at any rate) when airbrushing acrylics (similar for enamels but no doubt different here and there):
Air pressure. With a compressor many people use 20 PSI.
Thinning. With Vallejo
Model Air (specially made for airbrushing), they advise that no thinning is necessary. Some people do add about 10%. I don't thin it. You were, I'm sure, thinning your Humbrol acrylic far too much.
Distance from the part. I use about 6 inches.
Flow rate. At 20 psi I seldom pull the trigger more than about half way. (My needle size is 0.4 mm).
Flow rate and movement. Keep the flow rate constant and move the
airbrush smoothly. Start off the part and end off the part. Except for gloss varnish and gloss colours, don't go past the point when the paint starts to look wet. If necessary for evenness, apply another coat.
Primer. Some people don't use a primer. I always do. I think it helps the paint to go on evenly.
It takes practice but I got there in the end.