Airbrush problem help needed and very much appreciated!

[Burias-Drak'shal]

Hi all

 

I really hope someone can help me or point me in the right direction.

 

I have an infinity airbrush but have come across an issue I cant figure out.

Theres no air going through the airbrush tip and the paint is bubbling so I was assuming there was a blockage between the paint and the end of the needle/aircap.

However when you take the needle cap of exposing the needle and push for air it comes through okay but as soon as the needle cap goes back on no air comes through end.

Surely if the needle cap was blocked the airbrush needle wouldn't slide through it back and forth? I tried using cleaning brushes and putting airbrush cleaner over the cap and then trying cleaning brush again but no use?

 

Please any help much appreciated!

[Brother-Chaplain Kage]

I had something similar happen to my Iwata and I also thought it was a problem with the needle or the tip, but it ended up being some very thin paint build up in the section where the gravity feed meets the air channel. 

 

 

After several cleanings of the tip and needle with no change, I took the whole thing apart and had to use a tiny LED flashlight to look down the channel (my desk lamp and my head were too big to occupy the same space) and discovered the paint build up around the circumference of the channel. A few trimmed down Q-Tips soaked in alcohol later and everything was working properly again. 

[Brother Desultor]

I use this stuff to help clean away any build up of dry paint in my airbrushes. Anything not shifted by a blast with the precision nozzle straw is taken care of by a short soak.

As always, read the instructions and wear eye protection - especially when squirting into the confined spaces of an airbrush.

[Laughingman]

My Badger airbrush has a tendency to bubble back and not shoot when the nose cap is improperly screw on or the needle is improperly seated.. In terms of cleaning I find interdental brushes, 91% isopropyl alcohol and hoppe's 9 lubricating oil (a gun oil might not be widely available in the UK)  I can get get most acrylics out of my airbrush in a reasonable amount of time. 

[Arkhanist]

I suspect the problem might be the seating of the nozzle, as I had that exact problem when I first started using my infinity.

 

When you unscrew the aircap, the nozzle often comes with it as it's a floating nozzle and not attached directly to the airbrush body. With both of them off, you can see inside the front of the airbrush, and there's basically a flat bit - in the middle is where the needle comes through that the nozzle fits over, and a hole underneath where the air comes through to the front of the airbrush. There's a teflon seal on the nozzle where it mates with that flat bit around the needle. It's dead easy for paint to end up there if you take the aircap/nozzle off before the brush is completely flushed through (for example, if you try and clean the needle/nozzle mid session) - i had a thin layer of white primer in there and didn't realise which caused me no end of grief.

 

If the nozzle seal isn't completely flush against that flat bit by the air hole when you screw it back together, air will take the easier path around the nozzle and back along the paint path into the cup.

 

Other possibilities include a paint clog in the nozzle itself, or in the aircap where the nozzle fits through, as that will encourage air to flow back to the cup rather than draw paint off the nozzle (which is what creates the spray pattern) - just because the needle moves freely doesn't mean there's not a thin layer of dry paint in there somewhere that blocks air.

 

I use nail polish remover from my wife that has acetone in it. Soak a q-tip, and clean out that area where the nozzle meets the body of the airbrush, and the aircap. Both should be clear metal. Cleaning the nozzle itself is a bit fun, but you can do it fairly well with a interdental brush and dribbling a bit of acetone-based cleaner in there. I picked up the H&S service kit as that has a metal reamer that fits perfectly in the nozzle (unsurprisingly) that can clean out stubborn clogs, and some nice brushes to scrub out the paint channel from the cup to the nozzle seal (with nozzle and needle removed of course).

 

A can of spray airbrush reamer, usually xylene or acetone such as The Putrid One recommends will work instead of acetone nail polish remover, it's just the latter was cheaper and easier to find for me

 

To stop the nozzle sticking in the aircap, I put some needle lube on it (which you should have to lube the base of the trigger anyway). I also put a little lube on the screw thread of the body where the aircap goes on, that helps keep that sealed tight and prevents air leaking out that way. When reassembling the airbrush, I put the needle in first, then the nozzle and make sure it's seated, then finally screw the aircap on over both. Finally I push the needle forward as far as it'll go from the back, give it a little twist and screw that in place at the back, which ensures a good seal between airbrush, nozzle and needle.

[OnboardG1]

Oh god, I've spent hours stripping brushes when I couldn't find the source of a blockage so I feel your pain.

 

Aside from Arkhanist's excellent post, the other possibility is a perished nozzle seal. The PTFE o-ring around the nozzle and/or the tip cap can degrade and lose it's ability to seal the air pressure. 

 

By the way, when you buy new needles keep the old ones to ream the nozzle out. I have a reamer I got with my H and S airbrush and, while good, it's not quite as good as an old needle for getting the last of the crud out.

[Burias-Drak'shal]

Thanks found the blockage the tiniest amount of silver paint in the nozzle.