Future sprayed on chalk wash..

Great tip Abarne.thanks. i'll keep that in mind

If I understand your term, "chalk wash", which I am assuming is a heavy coat of pastel chalk dust, spraying a flat coat over it should not cause it to run, although the effects will mute somewhat. I use pastels all time, and then overcoat with Future+Tamiya flat base without trouble. Where you have a heavy build-up of chalk dust, try to hit it with a light fast coat that can sort of set it before making a heavier second pass.