Getting back into the hobby. I am using Tamiya flat acrylic dark grey to airbrush an older italieri panzer 38t. I have thinned the paint with just plain tap water. Twice I have airbrushed the model now (stripped it after botching the weathering the first go), and twice I have ended up with a very rough coat after airbrushing. This is much more drastic on the hull than on the turret. The only thing that bothers me about this is that when I put on a wash, this roughness really soaks it up and darkens the whole model considerably.
Is this something I am doing to cause this roughness, or could it maybe be the plastic or something. As I said it's much more drastic on the hull than on the turret which seems odd. Thanks for your help.