Hello Greg
Don't dismiss your existing airbrush just yet as your problem could be something as simple as an incorrect needle setting, the paint / thinner mixture, the pressure that you are using or even the compressed air supply.
Airbrushes are temperamental at the best of times and even the most experienced users have problems.
I have 2 airbrushes, an old Badger and a cheap DIY shop unit, they both operate at 28psi but the Badger can be temperamental especially during humid weather. Sometimes I give up on them and switch to using spray cans.
Can you tell us what make the brush is, what paint and thinners you are using and what kind of air supply you are using.
Paul