Quote:
Originally Posted by brushbyair
X I have had a blow up when I removed a bottle from the gun before, it was cause the vent hole in the bottle was plugged. That may be why it worked upside down, almost like a gravity feed instead of a suction feed.
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At least in theory, you shouldn't have the bottle or airbrush "Blowup" on you if the vent is closed, if anything, it should basically be doing a big inhale once the bottle is unscrewed, the vent is opened, or the bottle is removed from the airbrush. As you have stated, the airbrush is getting the paint by vacuum or suction, if the vent hole is blocked, that means that the brush will pull a stronger and stronger vacuum until it has hit it's limit because of the lack of strength of the vacuum, or a leak to the atmosphere has been introduced (the vent hole opens, the bottle is unscrewed, etc.)
If you are getting pressure in the bottle or cup, it is because the normal passage for air(out the nozzle) has been blocked, so the air takes the easiest path of escape, which in this case means back through the nozzle and into the bottle. The vent may or may not be blocked, if it is blocked, then the pressure will be greater, but even with it open, your compressor can push a fair amount of pressure back into the bottle, so much so that it can force paint up to block the vent.
But the real culprit is the blocked nozzle cap that won't let the air out to start with, or the nozzle that isn't seated snuggly or cleanly. If the nozzle doesn't seat well, then the air may find it easier to push back through the base of the nozzle and into the paint passage, and eventually into the paint reservoir/bottle/cup. I don't remember whether the Eclipse has a threaded nozzle or not, if it is threaded, you might try removing it, clean the threads on the nozzle and the airbrush, then apply some bee's wax to the threads and GENTLY reinstall the nozzle, these snap off easily, so be careful. If your problem is leaking threads, then the bee's wax should solve it, if not, then at least you have eliminated a possibility.
The airbrush may have been bubbling up without being noticed in the heat of the work day, and like all dirty needles, and nozzles, they only get worse until you clean them.
So, check the suction tube and cap fittings on your bottles, backflush your brush and clean it thoroughly, and make sure your vent is open.
If in doubt, try a different bottle or a cup in place of the bottle you currrently use on the brush. If everything is clean, clear, and tight, then the brush should work just fine with the sidecup and water, if it still stops up, then your brush is probably still dirty. Use a high powered jewelers loupe to do a careful inspection of the interior and exterior of the fluid nozzle and the nozzle cap.
If you can find one, a syringe that can take laquer thinner or denatured alcohol may help your cause. With the needle pulled back enough to open the airbrush nozzle, stick the needle/nozzle from the syringe into the opening for the bottle on the bottom of the airbrush, and force the solvent through. I found that a tiny syringe that comes with the refill kits for ink cartridges works great for this. The tiny needle works well for the gravity feed brushes becasue I can feed it into the same hole that the needle passes through at the front of the airbrush reservoir.
Good luck!