Troubleshooting

I have monitored several airbrush and modeling forums and I've seen a lot of postings about airbrush problems.  I've tried to help when I could, but sometimes it’s pretty tough.  How do you respond when somebody writes:   “My airbrush doesn’t work.  What’s wrong with it?”  Okay, that's an exaggeration, but not by too much.  So if you ask for help, try to give as much information as you can.  Include the airbrush brand and model, the type and brand of paint, the air pressure, exactly what the symptoms are, and what things have you tried so far.  I know this is just common sense, but many people just don’t think about it.  You will probably be advised to clean your brush again.  This is a pat answer, and sometimes it works.  And you may be frustrated because you know you’ve cleaned the darn thing several times already.  But it doesn’t take much dirt to mess up an airbrush's operation.  A tiny piece of lint can do it.  I would suggest you use a magnifying glass (the stronger the better) and a good source of light and really examine all the parts.

Some airbrush problems are really paint problems.  Before you blame the brush, see how it works with plain water or thinner.  Paint has to be really thin to work in an airbrush, especially if it has one of the smaller size nozzles like .2 or .3mm.

As you can see, if you’ve read the previous pages here, the airbrush is basically a pretty simple device.  But it is a precision device, and tolerances are tight.

So what kind of things can go wrong?

No air comes out

Obvious question:  Did you disconnect the air line from the brush and check that your compressor or other air source is supplying plenty of air?

Some trigger mechanisms are tricky to install.  Are you sure yours is in right?

If you remove the head assembly, there is a little hole in the main body where air should come out when you press the trigger.  See the photo on the right for its location on the 155. If air does come out, then the problem is probably something clogging the head assembly.  Hopefully, there is no dried paint blocking this little hole.  If there is, you may have to soak the body in something to soften it so it can be blown out.  Be sure to remove the air valve assembly before doing this.

If air doesn't come out, then the only thing left is the air valve assembly.  Be very careful if you dismantle it.  There are some very small parts and a tiny spring.  See the photo on the right for the 155 air valve assembly.  There is probably a little rubber O-ring that could be damaged.  If you’ve gotten lacquer thinner on it, it may have swollen enough to jam.  It may return to normal if you let it air out for a few days.  If not, you may have to replace it.  Make sure all the parts are clean and work smoothly.  Many advise applying airbrush lube.  I don’t, but I guess it couldn’t hurt.


Sticky Trigger

For some reason I seem to see this problem most often from Iwata owners.  They usually write that they clean the air valve assembly, and it works OK for a short time and then begins sticking again.  Sometimes they mention finding paint residue in the valve. Usually, several people will advise them to apply airbrush lube and the problem will go away.  But wait, if there is paint, where did it come from?  The only possible source is through the needle bearing.  Either they are pulling the needle out when there is still paint in the brush, or the needle bearing is leaking.  In some airbrushes there is an adjustment on the needle bearing that might stop a leak.  If not, or if that doesn't work, the bearing needs to be replaced.  For lubrication, most recommend regular airbrush lube.  But I have also seen WD-40 or Vaseline recommended by people who are pros.  I  don't use anything and my trigger works fine.

For Harder-Steenbeck owners:  I saw a video by Pro-Modeller that showed that the trigger can stick if the air valve assembly is too tight.  You might want to watch it.

Bubbles in the paint cup

First, make sure the head assembly isn't loose.  Snug it up, but don't over-tighten or you might strip the threads.  If this doesn't do it, then think about it.  The only way bubbles can happen is if there is a leakage from the air path to the paint path.  Now look closely at your airbrush.  If you have the type with a floating nozzle (aka tip), there is no gasket between it and the main body of the brush.  In the photo on the right, the arrows point to the surfaces where the parts mate.  Paint flows inside the nozzle and air flows on the outside.  The only thing keeping them apart is the metal to metal seal.  This seal is only good if both the nozzle body and the hole it fits into are perfectly round and dirt free.  One way to see if there is a problem here is to rub a little bees wax on this part of the nozzle and see if the bubbles go away.  If they do, you may need a new nozzle.

If your airbrush has a screw-in nozzle, then you probably have a gasket, possibly made of Teflon, to seal off the nozzle to body joint.  You didn’t lose the gasket did you?  Over time, these gaskets can be compressed enough that they leak.  This is an easy fix.  Just replace the gasket.

The only other place that air can get into the paint path is at the tip of the nozzle, like when you back flush by holding your finger or a paper towel against it.  I’ve read that paint build-up can occur here and cause bubbles.  I’ve never seen this, but you should probably check for it.

Intermittent spraying

I’ll just direct you to my page on replacing the needle bearing for this. Make sure it isn’t a paint problem.

Air but no paint

Other than a paint clog, sometimes people forget to tighten the needle lock nut.  They pull back on the trigger, but the needle doesn’t move; easy to fix once you notice it.

Make sure there is a vent hole in the cap of your siphon bottle or paint cup lid.  Otherwise a vacuum will form and stop the paint from flowing.

Bad spray pattern or spatters

Take a close look at the needle and nozzle.  A bent needle or cracked nozzle can cause this.  Acrylic paints seem to cause some problems.  I’ve never used them so I can’t comment.

Rough finish, orange peel, overspray, etc.

Sorry to tell you this, but it probably isn’t the brush.

In general, when you first get an airbrush, look it over carefully and study the parts breakdown so you understand how it works.  It's pretty clear from some of the questions that are asked, that many people don't.  I remember one instance where a fellow couldn’t get any paint out of his new brush.  Then he discovered that he hadn’t removed the protective cap.  At least he was man enough to admit it.

Also, if you’re still stuck, consider contacting the manufacturer or dealer.  My only experience is with Badger and Coast Airbrush, and they both have excellent customer support.


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