Mottled pattern when spraying

I'm not sure what you mean by mottled? Maybe you did not get even coverage? I noticed you did not say how much you thinned the paint! Even though it says ready for airbrush it isn't. You need your paint a bit thicker than milk. Your air pressure may be a bit high, but that that would not really explain your problem. I would thin that paint with distilled water (pure water). Not too much, about one drop water to ten drops paint. Then try again, if needed add a bit more water and try again. You may want to filter (strian) the paint before you load your airbrush. Get an old stocking from your wife (WITH PERMISSION) and cut a piece and put it over your paint cup and then load the airbrush. You most likely will see little clumps of paint that would normally cause problems.

Good luck!!

Been there done that.  The nozzle/ needle on your Custom Micron "copy" may be too small to handle the paint.  With every hobby-type of paint I've tried, a tiny needle like that spells difficulty...however it is possible.  Your solution, (in addition with DrweH's reply) may be to thin the paint more, little by little.  Keep in mind that with increasingly thinned paint may result in poor coverage.  An Iwata C/M such as your copy has a very tiny, .2mm needle that is designed for illustration work with very finely ground artist inks and the like.  I larger needle airbrush, such as one with a .35mm or 5mm nozzle/needle combo may be better suited for our thicker viscosity hobby paints.  And yes, you'll be able to do finelines with them as well with very excellent atomization and no spattered, mottled spray characteristics on the finish..  Just something to think about.

Here is a list of some popular modeling airbrushes, members here frquently use:

Badger 150, 100LG, 200 & Omni 4000, 6000 

Iwata Eclipse HP-BCS, BS, CS, and Revolution HP-CR, BCR

Paasche H, & VL

Testor/ MM/ Aztek A470, 3000S etc. (*buyer beware!, search posts before concidering)

 

Thanks. I've been eyeing the Eclipse HP-BCS as a replacement once I'm more comfortable with an airbrush. I didn't want to spend a lot of money initially and then find out I hated it.

Nik - you "should" be able to get Vallejo through that brush.. Try using distilled water to thin it at 10% then at 15%... Vallejo has a very finely ground pigment so you might be able to do it.  But I agree that a larger needle/nozzle brush will give you more fexability in the long run.  I have the Iwata HP-CR and love it!!!  The other brushes mantioned would be good too.  For finer detail and the option of overall coverage I am leaning toward buying a 100LG with M and F needle/nozzles or the HP-CS at present (with the HP-CR as backup)...