*%&# why does this happen?

Hello!

I've had it happen to me last year in the summer. I believe in my case it was a combination of hot air in my workshop and too much air pressure on my compressor. I was thinning the paint a lot and adding thinner often (you could sense how the paint gets thicker in the airbrush - it was this hot), but getting the air pressure down helped a little. You have to watch for the first symptoms of that thing happening while painting and do something about it before it covers the whole model. Hope it helps, have a nice day

Paweł

It was primer. Thanks for the help- I was particularly frustrated. I don't remember who said it but I believe it was from bouncing off another surface as there are many 90 degree angles.

I have since sanded and reprimed- all is well. thanks again

If this is your primer coat and not your outer coat, you may be able to sand the granularity down and just paint over it with your outer coat, or recoat it after sanding, which at least saves the huge headache of trying to strip it completely.

Groot

It looks like paint particles dry before hitting the surface. I had sandy, grainy marks when the paint was thinned too little and/or when I sprayed way too far from the model.

Sometimes spraying from too great a distance can do this.  Particles dry before hitting surface.  Usually not this big, more like sand.

I've had Rustoleum paints sprayed from the can do this to me.

It has happened with  new cans and cans that have been sprayed before.

It creates a huge mess as it has to be removed and that stuff doesn't want to come off. The part I sprayed took a week long bath in Purple Power and still required sanding and scraping to get it all off.

Agree (mostly) with above. It looks like the paint hasn't been thinned enough and/or airbrushing at too high a pressure and perhaps too great a distance.

looks like the paint "bounce" steve mentioned. the paint hits one surface, glances off, dries in mid air and sticks to the other wet surface, either that or the paint it just drying in the air between brush and model. try a bit more thinner and try not to spray at an angle so you dont get any bounce

Just some well meaning thoughts to consider

1. preclean the paint area thoroughly so dust, smuch, etc. is reduced (damp cloth should help)
2. test spray on a similar   type of styrene before the actual model to check for amount of air pressure (too high = paint drying before it hits the model)
3. make sure the paint is completely mixed ( paint vs thinner)  before spraying
4. use a good bright light to see the application on all surfaces.
5. Check that one surface doesn't "bounce" paint onto another, watch the angles -like a good pool  shot

Last but not least: keep trying; the secret is out there and you've almost gained

the exalted level to receive it

Sorry- the dusting is what I'm referring to.