Thinning Vallejo Model Color paints for airbrushing.

thin with distilled water,or their thinner.Don't use alcohol !!

I've used Liqutex and windex as well as Vallejo brand thinnner. But I echo the above post...DON"T USE ALCOHOL! It will turn to a blob.

I used the Vallejo thinner for both Model Color and Model Air (the darker colors of Model Air still need to be thinned down a fair bit if you're looking for fine lines, such as RLM 83), but switched to a bottle of Liquitex Airbrush Medium.  It's pretty much the same stuff... clear acrylic resin, retarder, and flow aid.  The Liquitex is much cheaper by volume, and the retarding function is better.  I still need to swab the tip every couple of minutes with the Vallejo thinner (their instructions even mention this), but it's much less often with the Liquitex medium, and if it's a 5 minute session and/or lighter colors I don't need to clean the tip at all.

Now that I've discovered White Ensign, Vallejo's kinda become my #2 paint, but I went through a lot of trial and error with the stuff when I was building my Dauntless. 

I've found thinning with water to be useless. By the time you get it thin enough to spray without immediately clogging, it comes out all, well, watery.

Airbrush medium has similar problems.

The BEST mix I found, almost across the board, is thinning Vallejo Model Color with Future. Sweet spot is around 1:1, give or take depending on your specific color or airbrush. The stuff will still clog up in the nozzle over time, but a quick dab with a wet q-tip will clear it up. I've found the Future has enough weight to it to keep things from going all watery, and it lays down really well in thin coats.

The other great thing about thinning with Future? Tough, glass-smooth, semi-gloss finish.

Cleanup with Windex, then flush thoroughly with water.

Also, a few caveats based on my experience:

1 - While the Vallejo can do awesome soft edges, I've found it doesn't like to spray fine lines at all. I wouldn't use it for pre or post-shading. Or mottled patterns like you'd fine on Luftwaffe planes. But for major surface colors, it's fine.

2 - Vallejo doesn't reduce very well. I've thinned Tamiya down to ridiculous levels for post-shading and stuff and still gotten fantastic results. Beyond maybe 4:1, though, Vallejo tends to separate in the thinning medium. 

I have used future too...thanks for the reminder Doogs. Thats the great thing about having a short memory...rediscovering "new" techniques with every kit. One of these days I will have to write what I do down so I dont have to ask "how did I do that last time"

I have used Liquitex Airbrush medium successfully with Vallejo. 

I am very curious about trying Future as suggested above. 

Great tips everyone!