Storing thinned paint

[Rob J]

In every article I�ve read about airbrushes they always say do not store thinned paint for long periods of time. Just how long is a long period of time and is there any way of knowing when thinned paint has �expired�?

[Ron Smith]

...

[Guest]

If you work with enamels, the thinner ( i.e. white spirit) will yellowish on light,
then wating your colors. If you work with acrylics (Tamiya, or beter Gunze) then
alcohool being "volatile" your paint pigments will "aggregate" at the bottom of
your storage can. Whan acrylics starts to aggregate, your color is dead.
If you work with inks, then you know one of the possible answers : transparency.

With airbrushes you master the "ratio" between air and paint. The key then is
thinning of the medium and care on applying soft layers.

So note how you created a color (i.e. 3 of Hxx plus 2 of Hyy then 1 of Hzz) and
when needing it again, just thin it a little bit and put several layers.

Perhaps you will not find this convenient, but for me it works.

Hope this helps,

Bruno.