Gravity pulls the paint down to the airbrush’s tip. The built up pressure makes the paint ‘want’ to get out and be sprayed.
Gravity continually forces the paint toward the airbrush’s tip to be sprayed. A gravity feed airbrush can spray with only a single drop of paint in the cup.
Compared to a siphon-feed airbrush…
Air pressure doesn’t pull paint up and out of a bottle. That extra air pressure atomizes the paint the better and more throughly.
The pressure normally used to pull the paint out of a siphon feed bottle instead atomizes thicker, chunkier paint better.
Of course, ‘thicker’ and ‘chunkier’ are relative terms–don’t get carried away. Think of gravity feed airbrushes as ‘more forgiving’ of your paint mixing mistakes.
Most spray guns have screw-in gravity feed cups of assorted sizes. Most airbrushes don’t have this optional feature. Instead they have small paint cups already attached to the airbrush body.
The biggest paint cups hold roughly .5 oz of liquid.
If you clean the paint out while it’s still wet, you shouldn’t have too many problems. Dried on, caked on paint is the worst.
It still takes longer than changing out a bottle though.
When in doubt choose a gravity feed airbrush.
Or rather, if you don’t have excellent reasons to choose a siphon feed or side feed airbrush then choose a gravity feed airbrush.The good tends to far, far outweigh the bad here, especially if you’re a beginner.
You can practice with small amounts of paint.
The airbrush doesn’t need as much air pressure to run. This becomes more of a necessity if you choose to use small airbrush compressors.
More forgiving of paint mixing errors. Everyone makes paint mixing errors.Pros mess up their paint mixes just as often as beginners. Beginners get far more frustrated by it though.
For the pros a gravity feed airbrush becomes the favored detail tool. Especially once they realize that…
less pressure = less over spray = finer details