how to clean airbrush between using different colours acrylics??

Flush out the remaining paint by spraying water through your AB until it runs clear. Then run half a jar (if siphon fed) or a 2 full paint cups (if gravity fed) of denatured alcohol through.

After the last of the alcohol goes through, keep the brush wide open for another 10 seconds or so to dry it out.

It should now be ready for your next colour.

Much depends on your what airbrush you have. I tear mine down (I have several brands) after each spraying session and clean them with either Windex or Lacquer thinner. Alcohol is a drying agent and I have found that it doesn't remove the paint residue from the depths of the brush. You may also find the need to scrub the recesses of your airbrush, here is a picture of the tools I use to do so.

Some are hobby related products, others can be found in the dental care section of your local drug store. 

Here's my sequence:

1. Dump any remaining paint in the cup/jar. Wipe cup fairly clean with paper towel.
   
2. Raise pressure to 40-50 psi, or as high as you can below that.
3. Blow 1/2 cup or jar of clean tap water through the brush, backflushing occasionally.
4. Blow 1/2 cup or jar of clean Windex through the brush, backflushing occasionally.
5. Rinse cup/jar with small amount of clean tap water, blow small amount through brush.
6. Blow small amount of distilled or deionized water through brush.
7. Blow brush dry and wipe out cup.
8. Reduce pressure to normal spraying range.

I spray plain water unless it is dried too bad and then I use some 91% Iso alcohol.

What you don't want is cleaners left over in the airbrush that can affect the next color.  

If I'm just going color to color (as opposed to cleaning up for the night), I just fill the color cup (gravity fed) with windex and use an old brush to swish it around and then blow it out.  Then use a little bit of fresh windex and blow that through, then just wipe with a paper towel.  Takes less than two minutes.

-Fred

Good point.  I may just start keeping a little glass jar of water handy.

Usually, if it was a particularly dark color, I shoot just a bit of of tamiya thinner through it (after the windex) just to make sure it's really clean.

I used to use just tamiya thinner, but then I realized 2 things; 1) I was going through a lot of thinner and windex is cheaper and 2) windex actually does a better job of cleaning up acrylics.  I don't know what's in there, but it really got out some old stubborn stains from the paint cup.

-Fred

Gigatron wrote:

I used to use just tamiya thinner, but then I realized 2 things; 1) I was going through a lot of thinner and windex is cheaper and 2) windex actually does a better job of cleaning up acrylics.  I don't know what's in there, but it really got out some old stubborn stains from the paint cup. -Fred

It's the ammonia! 

Hmmm...Good point   I guess it's a good thing I didn't get the ammonia-free windex then.

But, mine is the no-run formula; so far, I haven't noticed any adverse affects.

-Fred