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Airbrush Performance Drop

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  • Member since
    October 2021
Airbrush Performance Drop
Posted by PhoenixG on Wednesday, June 15, 2022 10:38 PM

Okay here's something I didn't expect from my airbrush. It suddenly started moving less liquid through it.  Paint, thinner, water, all are moving through airbrush slower than before.

Took it appart as lower paint flow is a sign of paint gunking up the inside of the nozzle.  However, when I went to clean it, there was practically nothing there.  It was efffectively clean.  Reassembled and same issue.

Took it apart again and did a thorough cleaning of all the parts and reassembled

However, now I notice air is being introduced into the paint cup whenever I start pulling back the trigger. Removed the shroud to verify the needle is moving back and it is.  Anything less than about half the throw of the trigger and all it does is introduce air into the paintcup.  No paint comes out of the nozzle though I can see space opening up around it.  I'm using an Optisight while doing this otherwise I wouldn't be able to see anything.

I didn't spot any cracks in the nozzle though there is a little unevenvess on a section of the rim.  Basically it looks a little rough.  Other than that it looks ok

Regulator is still set to 18 PSI so not an accidental change in pressure.  Cranked it up to just over 20 PSI but no discernible difference in behavior.

Any ideas as to what could be causing this?

On the Bench:

Bandai 1/72 Defender Destroid

  • Member since
    March 2022
  • From: Twin cities, MN
Posted by missileman2000 on Thursday, June 16, 2022 9:24 AM

Air blowing back into cup is another sign it needs cleaning.  Blockage may be too small to see, or in a region of the brush you cannot see.  Have you been using it for any clearcoats?

 

  • Member since
    October 2021
Posted by PhoenixG on Thursday, June 16, 2022 10:21 AM

missileman2000

Air blowing back into cup is another sign it needs cleaning.  Blockage may be too small to see, or in a region of the brush you cannot see.  Have you been using it for any clearcoats?

 

That's what I was thinking.  I did my usual routine of soaking the nozzle in thinner and carefully working the needle in it.  Usually if there is any blockage this will push out bits of crud.  Didn't find any this time.  Cleaned the channel in the airbrush where the needle resides in as well but little came out.  The airbrush is an Iwata Neo CN. 

I do use it for clearcoats.  Only thing that's gone through it are Vallejo's clearcoats.  The last time it was used to apply a clearcoat was many paint changes ago.  Well before this started.

Any suggestions of what else I might do for cleaning or inspect for?

On the Bench:

Bandai 1/72 Defender Destroid

  • Member since
    November 2018
Posted by oldermodelguy on Thursday, June 16, 2022 2:46 PM

If the tip is not seating correctly this can cause the bubbles. Try a little bees wax or lip balm on the mating surfaces and shoot some water through, see if the bubbles go away. Worth a shot,not saying this is the problem but I have seen it before.

  • Member since
    October 2008
  • From: Fullerton, Calif.
Posted by Don Wheeler on Thursday, June 16, 2022 4:35 PM

There is a tiny O ring between the nozzle and the body.  If there is a leak there, you will get bubbles in the cup.  The O ring should fit inside the body and not visible when the nozzle is installed.

https://sites.google.com/site/donsairbrushtips/home

A collection of airbrush tips and reviews

Also an Amazon E-book and paperback of tips.

  • Member since
    October 2021
Posted by PhoenixG on Thursday, June 16, 2022 9:19 PM

oldermodelguy

If the tip is not seating correctly this can cause the bubbles. Try a little bees wax or lip balm on the mating surfaces and shoot some water through, see if the bubbles go away. Worth a shot,not saying this is the problem but I have seen it before.

 

 
Hadn't occurred to me that there might be a poor seal by the tip.  Definitely worth investigating.  Interestingly enough I have beeswax but no lip balm/chapstick.  Will have to give that a try tonight.

On the Bench:

Bandai 1/72 Defender Destroid

  • Member since
    October 2021
Posted by PhoenixG on Thursday, June 16, 2022 9:23 PM

Don Wheeler

There is a tiny O ring between the nozzle and the body.  If there is a leak there, you will get bubbles in the cup.  The O ring should fit inside the body and not visible when the nozzle is installed.

 

Hi Don,

     Sounding more and more like I may have a bad seal at the nozzle.

Took a look at your site.  Possibly the best organized general airbrush information I've come across.  Thanks!

On the Bench:

Bandai 1/72 Defender Destroid

  • Member since
    October 2021
Posted by PhoenixG on Friday, June 17, 2022 8:32 PM
 
Was able to test this tonight with bees wax and  the problem went away. Looks like the o-ring on the nozzle needs to be replaced.
 
Thank you!Bow Down

On the Bench:

Bandai 1/72 Defender Destroid

  • Member since
    November 2018
Posted by oldermodelguy on Saturday, June 18, 2022 9:08 AM

PhoenixG
 
Was able to test this tonight with bees wax and  the problem went away. Looks like the o-ring on the nozzle needs to be replaced.
 
Thank you!Bow Down
 

Perfect ! Meanwhile keep the old O ring and just use a little bees wax along with it till you get the new ring.. Some guys use the bees wax on reassmbly anyway even without a bad O ring.

  • Member since
    October 2019
  • From: New Braunfels, Texas
Posted by Tanker-Builder on Saturday, June 18, 2022 11:43 AM

I have to pipe in here!

    Hey, guess what.Y ou hit the nail on the head! "O" rings are not that easy to find anymore in General.You can get them from, probably Micromark. I go to the De Vilbiss distributer in San Antonio for mine. My old  De Vilbiss Auto striping and Mural(Vans and V.W.s) unit still sprays like new and it's about fifty five to sixty years old now. My Binks and Paasche units are getting whiskers too. But with proper maintenance they have lasted this long. I just am not comfortable with anything that has a lot of Plastic on it even if it's only the handles.

  • Member since
    October 2021
Posted by PhoenixG on Saturday, June 18, 2022 4:51 PM

Tanker-Builder,

You're spot on.  Having zero luck finding a suitable replacement o-ring.  Not sure I see the point in spending $15 to replace the entire nozzle when that's needed is a pennies cost o-ring.  I can live with replacing the bees wax until I wear out the nozzle.

This was probably caused by overtightening the nozzle during reassembly, crushing the o-ring in the process.  Chalking it up as a lesson learned with my first airbrush.  Not bad for my first year with one.  I was pretty sure it would be the needle I'd destroy first.  Smile

On the Bench:

Bandai 1/72 Defender Destroid

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