AIRBRUSH TECHNIQUE - LEARN TO AIRBRUSH - View Single Post

fontgeek · 07-22-2008

The only way paint would be forced back through the paint passage, and past the needle packing/bearing/seal, is if it can't escape or release pressure through the paint reservoir cup or bottle. If your brush is packed up that bad, then some paint getting past your packing is the least of your worries. I'm not doubting they told you this, I am doubting the person(s) understanding of what you are saying, or of how an airbrush works.
The paint and air are going to take the easiest route of escape, in normal operation of an airbrush, that is through the needle and nozzle caps for the air, then, if the opening in the nozzle cap is blocked, it, the air, passes back through the nozzle, through the paint passage, and into the paint reservoir, where it makes your paint or solvent bubble. All backflushing is is you, the operator, doing this on purpose.
For the paint to be forced past the needle packing/seal, it would mean that all other exit points for the air have been blocked, that includes the nozzle and needle cap, the paint reservoir cap or lid, the lid vent hole, the male and female openings for the siphon or side feed variety of brushes, and the fittings on those bottles or cups.
Personally, in the 30 or 40 years of airbrushing I have had, I have never seen a brush so plugged that it would or could push the paint back past the packing/seal. If the paint is so dried and packed that it can't go out via the reservoir, it is way to dry or thick to go past the packing.

As far as your packing being exposed to the paint itself, it gets that everytime you airbrush, that packing just acts as a squeegee, and wipes the needle clean when you pull the trigger back. No more, no less.

07-22-2008	#9 (permalink)
fontgeek magazine subscriber Join Date: May 2006 Posts: 441	Re: the paint skips The only way paint would be forced back through the paint passage, and past the needle packing/bearing/seal, is if it can't escape or release pressure through the paint reservoir cup or bottle. If your brush is packed up that bad, then some paint getting past your packing is the least of your worries. I'm not doubting they told you this, I am doubting the person(s) understanding of what you are saying, or of how an airbrush works. The paint and air are going to take the easiest route of escape, in normal operation of an airbrush, that is through the needle and nozzle caps for the air, then, if the opening in the nozzle cap is blocked, it, the air, passes back through the nozzle, through the paint passage, and into the paint reservoir, where it makes your paint or solvent bubble. All backflushing is is you, the operator, doing this on purpose. For the paint to be forced past the needle packing/seal, it would mean that all other exit points for the air have been blocked, that includes the nozzle and needle cap, the paint reservoir cap or lid, the lid vent hole, the male and female openings for the siphon or side feed variety of brushes, and the fittings on those bottles or cups. Personally, in the 30 or 40 years of airbrushing I have had, I have never seen a brush so plugged that it would or could push the paint back past the packing/seal. If the paint is so dried and packed that it can't go out via the reservoir, it is way to dry or thick to go past the packing. As far as your packing being exposed to the paint itself, it gets that everytime you airbrush, that packing just acts as a squeegee, and wipes the needle clean when you pull the trigger back. No more, no less.