I'm doing something wrong.

what pressure are your spraying at?

I know it's between 12 and 16, I haven't  moved the pressure in over a year. Just kept it there and oainted everything with it.

What's the local air temp? Is it hot and dry? Also, what are you thinning your paint with?

It's up to you, but you might try more thinner. Tamiya acrylics can be thinned pretty lean and seem to work better that way.

Right now it's 86 F dreeges outside and it did rain this morning.

I'm using Tamiya acrylic thinner, one part thinner and two parts Tamiya acrylic paint.

I have thought about thinning it ever more but wanted to check on here first.

86F (or about 30C) would surely be enough to give you tip dry if you're only thinning the paint 1:2.  

Using Tamiya X-20A thinner, you could take it to about 3 parts thinner to one part paint before it starts to bead and run.

Thinning with denatured alcohol or Tamiya's lacquer thinner, you can take this considerably further and the paint will still lay down cleanly. When you run the paint this thin, you need to use lower air pressure and layer the paint, rather than try to get "one pass" coverage.

I was trying to layer the paint with 3-4 light coats.

Well I guess I'll start thinning it more than I was.

Thanks for the help!!

i always thin 50/50 with new pots and a bit more thinnner with half used post at about 16-18 psi. if i am doing small stuff ill up the pressure to 22-24 and thin a bit more but only spry tiny amounts of paint at a time or it will run horribly. this is with a 0.3 nozzle. i only use a 0.2 nozzle for very thin paint cellulose paint or alclad.

I would wonder if the weather (temp, humidity) is what is causing the tip dry. I use a paasche vl and used to struggle with tipdry on acrylics. I removed the airbrush tip and ground it off until the needle was fairly exposed. This allowed me to wipe it off easily with a napkin. This really, really helped. Cant recall how the end of the iwata looks so this may not be a solution for you.

Chis

I mix my Tamiyas with laquer thinnner from Guynze...never had an issue, but thinning it with water or anything else I always get tip dry. All my acrylics get it some quicker than others.