enough is enough.......

Paasche H for inexpensive simplicity.  Maybe a Badger 200NH or its double-action cousin 155 Anthem for a bit more performance.  Badger 100 double-action gravity feed for yet more performance.  Properly used, any of the above will give excellent results.

You didn't describe the nature of the problems that you experienced with your Aztek.  Airbrushing consistently well does take practice and experience.  From my own experience learning to airbrush, the problems I had early on with getting consistent results were more often than not due to my own inexperience.  So you may find that a new air-brush is nice, but that it might not make your problemsgo away immediately.

Andy

Could very well be "pilot error" :)  Probably is. It seems that I can paint a dozen objects and everything goes well, turn around 10 min later to do the next one and it spits and sputters like an old worn out motor. Could be the cleaning method but I always go thru the same steps. I'm pretty mindful of how it gets cleaned. I use acrylic about 99% of the time. I just think it's time for an upgrade. I've had this thing for a couple of years now. Maybe it's time to lay it to rest or maybe I'm looking for an excuse to upgrade. Thanks for the suggestions. I'll check 'em out.

Hud

Make sure you are not experiencing "Tip-Dry". Common problem with acrylics. I say this, becuase if this is so, you will have the same probs with ANY airbrush. I have an Aztek and Badger100LG. I use both. I like the "feel" of the Badger a little better, but they spray relatively the same IMHO.

See here:
http://www.finescale.com/FSM/CS/forums/542852/ShowPost.aspx

Is that an external mix Aztek?

QT

Yup-- if you are using acrylics mainly-- it's best to go pick up some retarder at any craft store-- a few drops of that added to your thinned paint will mostly prevent tip drying from occurring...

Hud - if you are just getting the "I've done all I can do with the brush" feeling.  There are several good brushes which are an upgrade to the one you have but won't break the bank:

Siphon fed:  The Badger 155 will handle large coverage to medium detail just fine!  The Iwata HP-CR is also a good brush, can handle large coverage to a little bit finer detail just fine.

Gravity fed:  Badger 100LG with a medium and fine needle/nozzle.  With both tips this brush can do a lot!  Iwata HP-CR it can handle almost every job, I own this one plus the Badger 155 and this is my favorite...

All of the above brushes typically run roughly about $70 plus the airhose. (Badger and Iwata have different size connections on them, neither of which will work with an Aztek hose)

Thanks guys for the suggestions. I found a bargain ( I think) on an airbrush yesterday. It's another Testors a/b, ModelMaster GP-100. Had a date stamped on the instructions, 1999, so it's not the newest thing around but it's an internal mix, fixed double action. Came with a nice case and a couple of accessories. Twenty five bucks, brand new in the box. After knocking the inch off dust of the box  I found the sticker, $49.95.  I said "what the h...", go for it. Used it last night, works like a champ. Time will tell if my prior a/b problems go away. Thanks again.

Hud

I think that Azteks suffer like many other things of lowering quality due to imperatives of mass production, maybe more than "metal" airbrushes, so to say that getting a new old airbrush could have been a great luck as they were better than now in the "good old days", in my opinion. The first one I owned, the 1000 if I remember well, was wonderful; then I bought a Contempo ( the blue transparent one) then a 4709 box, and the two latter made a terrible squeak when I screwed heads on them; the first one did not. I mean that they seem to be cheaper made as time goes by, so you might have found  the "oiseau rare". Congratulations  !