Arghh! Yet another airbrush disaster!

QUOTE: The speckling is hard to describe. It's almost as if the paint has dried mid flow but it actually hasn't. weird!

That isn't an uncommon problem, but it's more prevalent with acrylics than with enamels. It can usually be cured by lowering the air pressure or spraying closer to the model.

QUOTE: Does anyone use acrylics? I've always had better results with acrylic rattle-cans than enamel so i'm considering an (expensive!) switch.

I use acrylics almost exclusively. I'll occasionally spray some enamel or laquer but it's nearly always from a rattle can.

Thanx guys, i was hoping for some responses before the weekend, i've only got net access at work at the moment so i needed some enthusing before i leave!
The speckling is hard to describe. It's almost as if the paint has dried mid flow but it actually hasn't. weird!

yet more practice and striping new paint to come then! Does anyone use acrylics? I've always had better results with acrylic rattle-cans than enamel so i'm considering an (expensive!) switch.

By speckling, do you mean something like micro clumps? That happens with enamels once they've expired. I never have been able to fully renew enamel that has degraded to airbrushing like that.

The very few Humbrol enamel paints I have used seem to have an extremely long life compared to Testors, but they also sit on the shelf at the local hobby shop for a whole lot longer too. I don't know if your Humbrol cans have expired before you got them. It's a guess I'm making.

Music is on the money Rob.
Dont be distracted, it just takes a bit of trial and error to find what works for you and your setup.

From what you described, I would look at pressure first, the speckle would most likely be that, or paint being to thick.

The pooling would be to much paint flow, vs distance and speed across project.
Patience is the key.

Airbrushing is a triangular procedure in that there are three things that affect the finished job (5 if you include the airbrush and operator). They are 1) Paint consistency, 2) Air pressure, 3) Distance from the surface. To get a good paint job they all three have to be balanced within a relatively wide range. If your paint is too thin or the pressure is too high or you are too close to the surface you will get a runny finish. Likewise, if your paint is too thick or your pressure is too low or you are too far from the surface you'll get speckling.

I usually thin my paint about 3:1 (paint: thinner), spray at about 15 psi, and spray from about 3-4" from the surface. These will vary from airbrush to airbrush but should be a good starting place.

Humbrol is good paint and enamels usually spray very well. It sounds like yours is thinned about right so I'd suspect that it's either the perssure or your distance from the surface that is causing your problems. Try playing with your air pressure and see if that helps. Also make sure your airbrush is thoroughly clean and you don't have any air leaks along the hose anywhere (spray some soapy water on all the connections and look for bubbles).