Problem with lacquer through airbrush - can anyone help?

Hi guys,

I've decanted (messily!) some Tamiya TS spray and started shooting it through my airbrush. I'm using Tamiya lacquer thinner, with probably a 3:1 paint/thinner ratio. Anymore seems to thin it too much so as to be a washy white thinners mix that's unsuitable for a topcoat.
Temp has been in low 20's (C), and humidity is about average. Shooting at about 35-40psi using reasonably new Iwata airbrush (cleaned regularly).

I'm finding that often when I shoot this stuff it can leave a VERY grainy appearance in some areas. On the odd occasion it's also as if rather than going grainy it sort of forms into little hair-like... 'things'. As if lots of small hairs fell on the job just as I was spraying.

On the heavier areas it's not there very much at all, which leads me to believe it could be a spray volume thing. But then it hasn't done it in all areas... and others have had success with mist coats, etc.

It's going to be impossible to spray a mist and final clear topcoat when I come to it if this problem persists (although currently shooting white).

Can anyone help me stop this problem???
I've got no more tricks up my sleeve.

Thanks all,
M

I use a 'High Quality Laquer thinner' that I got from a local paint supply store. I had the same problem when I first started decanting the Tamiya paints. I ended up mixing the paint/thinner to about 50% mix. I also thought it was too thin but the thinners dry very quickly.

I've only decanted and airbrushed TS one time, but I've airbrushed it directly without thinning it and the paint was fluid enough through my Iwata HP-C @ around 20~25 psi.
Probably metallic colours may need a bit more pressure due to their "thicker" consistency...?

Sounds like you are getting veiling due too your lacquer being too thick. Sounds like you need to thin more. Check out the tutorials on Cobra colors (http://www.cobracolors.com/) site. Very informative and helped me out immensley.

Since you've already tried thinning the paint, try a much lower air pressure-you might get much better gloss starting in the 10-15 psi range-work up from there until you reach a happy medium-Tamiya spray decants w/o needing much thinner (if any) to work well through an airbrush. I think excessive pressure is causing the paint to dry much too rapidly before it hits the surface.

I think a bit more testing is in order - thanks for the tips guys, I'll give it all a go tonight!

There was an article on this in a recent Fine Scale Modeler: The author decanted some paint and sprayed on an overall mist coat lacquer straight from the can at about 10psi, and then when it cured he did a single wet coat with the can. He says he didn't do any finish work and it looked great.

I've tried adding more thinner, to a ratio of about 1:1 and the problem appears to have vanished!

Time will tell I suppose, I've got a bit more experimenting to do... but hopefully I'll find some success and have the body of this damn BAR finished this year!