Spray Paint In SPray Gun?

Ok I work at a autobody shop and of course with mix our paints from powder, however i have heard of people tipping a spray can over pressing it down and releasing the pressure, and then cuttin can open and putting it in a spray gun we use Gravity Feed HVLP Spray guns. So what I am wondeirng is wont this gum up the gun parts, or if you clean the gun therouly after use with thinner would this work?Spray Paint In SPray Gun?
I would not put that crap in my expensive guns.

acne treatment