Airbrush charges the paint bottle rather than drawing liquid

homyakchik · Post by **homyakchik** » Sat Mar 10, 2012 6:40 pm

If anyone can suggest a fix for this, I'd appreciate it.

I've got three airbrushes (one of which I can't find; it's an actual mostly-metal Badger something or other). The two are inexpensive ones. One is single-action; the (or a) bottle appears to screw into a permanent holder in the front of the thing, and the air from the brush blows past a top of some kind, spraying. (I haven't found the bottle for this one, although I know I've used it in the past.)

The other one is a dual-action (forward/backward trigger), and the brush has a connector on both sides for the bottle-with-tiny-tube (I can hook the bottle to either side, depending on how it's comfortable for me). Have the bottle (and bunches of spares). The tiny-tube top is (I think) missing a hose that extends down into the paint/substance (I've been testing with water). No search has turned this up (or, in this room, is likely to).

I tried hooking the 'paint' bottle to the airbrush without the tube inside. Air comes out of the brush, but no water. HOWEVER, the air appears to be pumping _into_ the bottle like that; when I push the trigger (either way) I get a spray of water out of the paint bottle's breather hole until the liquid level drops too low for this to continue.

I found an old hospital substances tube (sister-in-law: Nurse. Always saves me interesting-looking bits and pieces) that's the perfect fit for the tiny-tube bottle cap. Clipped a length off, stuck it in. When I press the trigger I get another spray out of the breather hole, but not for long. If I cover the breather hole with my finger, I can see bubbles going _into_ the paint bottle (essentially pressurizing it), explaining the spray-from-breather-hole trick.

I thought airbrushes worked by the airflow pulling paint/substance (I wanted to spray some matte) up through that tube, and thus either (a) am wrong or (b) can't figure out what's up with the airbrush. (Actually, (b)'s true regardless.)

Does this sound familiar to any veteran airbrush jockeys? It's been two, three years since I used any of these. I made sure to keep them clean, and as I said, there's definitely airflow at the needle. But instead of sucking up the tube, it's pushing the air down the tube, and the paint/substance hasn't anywhere to go.

Any ideas, anyone?

Thanks

Davey

Kylwell · Post by **Kylwell** » Sat Mar 10, 2012 10:49 pm

Siphon feed brush work by creating a low pressure over the siphon, the tube attached to the paint reservoir. 2 things can hamper this, the breather hold being clogged enough to no allow airflow and the feed tube being dirty enough that the low pressure effect gets disrupted.

Clean it thoroughly and carefully and make sure the vent hole is open and free of obstructions.

Joseph Osborn · Post by **Joseph Osborn** » Sun Mar 11, 2012 12:47 am

Davey, what you're describing sounds like a clogged nozzle. Are you certain the tip/nozzle is completely clean? If in doubt, clean it some more, preferably by soaking the tip in some lacquer thinner for a while. Make sure you're just soaking metal and no type of o-ring or seal along with it. If you have some beeswax, rub a little on the threads when you put it back together; that will help keep the air pressure inside the body and prevent the back-pressure. Hope this helps.

homyakchik · Post by **homyakchik** » Sun Mar 11, 2012 4:48 pm

Thanks to both of you; I dismantled the airbrush for which I have a bottle and let the pieces (including the airbrush) soak in hot water. Still warm by the time I got back from Church, but a test (after a scrub with a toothbrush) showed that it was actually working again. There hadn't been much to see on the parts; I guess I just missed a teeny bit a few years back when I last used it.

But I got that matte coat laid down on my A27 buildup, and right now it looks dead-flat and reasonably realistic. Time to start dirtying it up more.

Thanks again!

Davey

Kylwell · Post by **Kylwell** » Sun Mar 11, 2012 5:01 pm

Depending on the paint hot water may not do it. If you can find Windex with ammonia it'd clear most non-solvent based paints out.

irishtrek · Post by **irishtrek** » Sun Mar 11, 2012 11:42 pm

Like JO said SOAK the compnents in some thinner over night!!!

Kylwell · Post by **Kylwell** » Mon Mar 12, 2012 10:11 am

Depending on the airbrush that could ruin the seals. It's why I prefer a little bit of work with a small brush (even a modified q-tip will do) and solvent rather than soaking it.