Author Topic: Air Brush Issue  (Read 909 times)

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BCR751

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Air Brush Issue
« on: January 03, 2014, 02:06:37 PM »
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I have a Badger 200 airbrush.  I've noticed that, when applying paint, in addition to the regular spray pattern the airbrush is shooting out large drops onto the model.  I keep the tip clean, I'm not using a wide spray pattern and the paint has consistent viscosity.  I can't figure out why the airbrush is doing this.  Any ideas?

Doug

peteski

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Re: Air Brush Issue
« Reply #1 on: January 03, 2014, 02:22:45 PM »
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I have the same airbrush, and have been using it for decades.

You don't mention what paint you are using.  Air pressure?

In situations like this, the very important question is "what has changed since last time the airbrush was working ok".  And don't say that everything is the same, obviously something is now different.  :)

Also, you say that you keep the tip clean. How about everything inside (the paint path)?  While I usually just run lacquer thinner through mine until it comes out clear, I do take it fully apart about once or twice a year.

There is a gasket under the head (white Teflon, shaped like a slice of tubing).  I tried to reuse it, but that caused the air to leak into the paint path.  That is because once compressed, Teflon doesn't seem to bounce back to its original size. That results in imperfect seal. Now anytime I take the head off, I replace that gasket.
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BCR751

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Re: Air Brush Issue
« Reply #2 on: January 03, 2014, 02:38:29 PM »
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I am using Tru-Line Trains Clear Glaze paint.  It is a water-based acrylic that doesn't require thinning prior to spraying. Air pressure is 20-25psi.   I have used this airbrush for, probably, 30+ years.  Things that are different.....let's see, I recently replaced the Teflon gasket and the entire tip (standard tip) assembly.  The first one finally wore out. Nothing else has changed.  After replacing this stuff, the airbrush worked fine, no large drops, good coverage.  I spray about 4-5" away from the model in continuous smooth parallel strokes which gives about an inch wide spray pattern.  I completely disassemble the airbrush after each painting session and clean each part thoroughly.  I check the gasket and, although it would be hard to see any defect, it appears to retain its shape.  I had a hell of a time finding a replacement gasket and had to go to Badger direct to get a couple.

Any clues in the above as to why I'm getting the large drops?

Doug

Scottl

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Re: Air Brush Issue
« Reply #3 on: January 03, 2014, 02:47:08 PM »
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Do you have a water trap in the air line?  Maybe some condensation is in the air, or cleaning fluid?  I had issues like this when my needle tip was bent as well.

BCR751

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Re: Air Brush Issue
« Reply #4 on: January 03, 2014, 03:11:46 PM »
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I'm using a commercial air compressor that has the water trap inline.  I check it often and haven't noticed any water accumulation.  I am very careful when disassembling the airbrush not to damage the needle.  I did bend one a long time ago so I know how easily they bend.

Doug

tom mann

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Re: Air Brush Issue
« Reply #5 on: January 03, 2014, 03:18:35 PM »
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I would look at the needle very closely.  Is sounds either dirty or slightly bent at the very tip.  If not, maybe the paint is from a bad batch?

peteski

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Re: Air Brush Issue
« Reply #6 on: January 03, 2014, 04:20:28 PM »
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Have you ever in the past sprayed that exact paint  (from that bottle) through that airbrush without spattering?
How about trying another Tru-Line color which sprayed fine through the airbrush in the past?
--- Peteski de Snarkski

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Bobster

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Re: Air Brush Issue
« Reply #7 on: January 03, 2014, 05:59:01 PM »
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Greetings,

I have used a Badger 200 for 20 years.  My thoughts would be to check the nozzle that the needle slides through for a crack.  Its the little brass piece that can be seen when the tip with the 4 holes is removed.  A crack can occur when the two "knurled" nuts at the back end are tightened, if the needle is all the way forward when this is done.  And IF that is what happened it will be a tiny crack.  50-0392 or 50-0393, I believe is the part.  You will need to consult the proper parts diagram.  This comes from a former hobby shop owner who I consulted.

I got a tiny nick inside in the 4 hole part,  when I dropped my airbrush. It disturbed the airflow enough to cause a similar situation.  I had to replace this piece.  I believe in later years this 4 hole part has been replaced by a "saw tooth" tip.

These two could cause the condition you describe.

Just my 2 guesses,
Bob

BCR751

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Re: Air Brush Issue
« Reply #8 on: January 03, 2014, 09:47:10 PM »
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An update.  I played around with the airbrush this afternoon and found something I hadn't noticed before.  As I'm spraying, I keep checking the nozzle (the one with the four holes) and I noticed a slight build-up of paint on one side of the inside of that nozzle.  I think as the spray comes out, it's picking up the "blobs" from that deposit.  I checked over the assembly with a magnifying lens and I can't see any cracks, nicks or anything else that may cause that build-up.  The needle appears straight to me although it is the original (30+ years old now) so maybe that is causing it.  I'm at a loss to come up with any other solution.  Maybe all I need to do is to keep a Q-Tip handy and clean out the nozzle frequently to prevent any build-up.  However, I really would like to find out the cause of the build-up and see if it's fixable.

Doug

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Re: Air Brush Issue
« Reply #9 on: January 04, 2014, 12:37:01 PM »
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I believe it is the paint. Strain the paint with a mesh and check for clumps.

BCR751

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Re: Air Brush Issue
« Reply #10 on: January 04, 2014, 03:41:42 PM »
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I use the screen strainer that comes with the airbrush.  There are not many things that are finer than that so I don't think straining is the issue.  And yes, I have used this very bottle of gloss glaze previously with no problems.  It went on just as it should and I was using the same setup I'm using now.  I had another look at the brush parts and I'll be damned if I can see anything wrong with them.

I read in another forum that someone suggested keeping that four-hole nozzle clean during the painting process so maybe I just need to do that.  Funny thing is, however, that this issue just cropped up after 30+ years of using the airbrush. :?

peteski

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Re: Air Brush Issue
« Reply #11 on: January 04, 2014, 05:10:20 PM »
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Doug, let me ask again: is this the first time you tried to use that particular paint?  Do other paints shot through the same airbrush have a problem?  That will quickly answer whether the airbrush or the paint is the culprit.

As far as that nozzle goes, I damaged mine several years ago (bent its outer lip). I filed it down to the bottom of those 4 holes, and I have never had a problem with that setup.  That might work for you too.

Someone else mentioned that this part was redesigned int a crown-shaped nozzle.  They might have done that to prevent the problem you are seeing (with certain brands of paint?) .

So, you could either try filing down your nozzle, or buy the new type of the nozzle and try it.
--- Peteski de Snarkski

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BCR751

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Re: Air Brush Issue
« Reply #12 on: January 05, 2014, 06:59:03 PM »
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I think I'll get replacement parts for the entire tip and start over.  And, while I'm waiting for those, I'll just keep the tip clean with a Q-Tip and some isopropyl.  I sprayed the same paint using the same equipment again today and it went on without a hitch.  Maybe it's the humidity, or maybe I didn't hold my mouth right the other day.  Who knows? :facepalm:

tom mann

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Re: Air Brush Issue
« Reply #13 on: January 05, 2014, 08:13:49 PM »
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If the acrylic isn't thinned enough, it can actually dry in mid air, resulting in gobs on the surface.