Air Surge Question

Since you have a large capacity compressor and tank, I doubt if you are pulling it down.  My guess is a restriction in the line before the regulator gauge.  Can you temporarily take out the desiccant or or the moisture trap?  It could also be a bad regulator.  If you sealed the joints with Teflon tape, you didn't by chance partially cover the end of the pipe did you?  Just some thoughts.

Don

Thanks Don, I will try your suggestions when I get home tomorrow.  Also, thank you for your website.  It has been very helpful and very informative.  You have done a great service by putting all that good info out there.

Cheers,

Greg

Thank you, Greg.  I'm glad to hear the site was of some help.

I hope you figure out your air problem.

Don

You also set your working pressure with the trigger depressed or pulled. You don't set it while the brush is static or not spraying. The only way to adjust the working or spraying pressure is with the airbrush spraying. Typically an airbrush will handle significant pressure, but for our applications we stay between 8-18 psi.

HawkeyeHobbies

You also set your working pressure with the trigger depressed or pulled. You don't set it while the brush is static or not spraying. The only way to adjust the working or spraying pressure is with the airbrush spraying. Typically an airbrush will handle significant pressure, but for our applications we stay between 8-18 psi.

It depends on the quality of the compressor too. It shows the importance of getting a good compressor with sufficient pressure and airflow capability.

I use an Iwata Eclipse HP-CS typically at the 15-20 psi pressure range. The compressor is a Paasche DA400 twin piston, older made in Taiwan model. After I set the pressure using the regulator knob, the pressure will drop 0.5-1 psi when I pull the airbrush trigger to fully open position. It is accurate enough for most modeling task. It makes little difference whether I set the pressure with or without the trigger pulled.

It is not the same situation when I used to have a Silentaire Scorpion-1 compressor (the old 1000A model dated 10-15 years ago) with a Paasche H airbrush. No matter what pressure I set before hand, the gauge reading drops to less than 10 psi when I pull the trigger. And the pressure does not respond to regulator setting when the airbrush trigger was pulled. It is an indication that the compressor did not have enough power to drive the airbrush I used.

Greg, what make and model of compressor are you using? Does the pressure gauge reading respond to you changing the pressure setting when the trigger was pulled? If it does, you may have other setup problem.

Do not load the airbrush with paint. Just let it  blow air. Put your bare palm in front of the airbrush and pull the trigger all the way back. Do you feel the air gradually diminishing? If not, it may just be an air pressure gauge setup issue.

Thanks Keilau and Gerald.  My compressor is a standing garage type with a 30 gal tank with a maximum output pressure of 150 psi.  When I push the button on my sa ab (badge 200nh) it does give a burst of air then bleed down.  My da ab (aztec) does the same thing, just easier to manage because I can bleed the air down before I flow the paint.  I tried two different pressure regulators, with and without the dessicant.  I didn't get a chance to trouble shoot the whole system due to time restraints (ie wife had other priorities for me!).  Could a coiled airhose, the 1/4" npt one, cause a reduced residual pressure?  I know in water hydraulics, curled hose causes friction loss in pressure, but not like this.  A big static pressure, but little residual pressure, but how could a little airbrush outstrip the supply brought to it by a 1/4" npt line?  Hmm.  I think Don was onto something, I just have to go through the setup and find the weak link.  I'm thinking about trying else on the end of the air hose, and see if that bleeds down.  If not, then it will be in the airbrush setup.  Makes sense, right?  Thanks again guys.

Cheers,

Greg

Gregbbear

Thanks Keilau and Gerald.  My compressor is a standing garage type with a 30 gal tank with a maximum output pressure of 150 psi.  When I push the button on my sa ab (badge 200nh) it does give a burst of air then bleed down.  My da ab (aztec) does the same thing, just easier to manage because I can bleed the air down before I flow the paint.  I tried two different pressure regulators, with and without the dessicant.  I didn't get a chance to trouble shoot the whole system due to time restraints (ie wife had other priorities for me!).  Could a coiled airhose, the 1/4" npt one, cause a reduced residual pressure?  I know in water hydraulics, curled hose causes friction loss in pressure, but not like this.  A big static pressure, but little residual pressure, but how could a little airbrush outstrip the supply brought to it by a 1/4" npt line?  Hmm.  I think Don was onto something, I just have to go through the setup and find the weak link.  I'm thinking about trying else on the end of the air hose, and see if that bleeds down.  If not, then it will be in the airbrush setup.  Makes sense, right?  Thanks again guys.

Cheers,

Greg

It is getting more intriguing. With the amount of air an airbrush (Aztek or Badger) uses, it should take forever to bleed down a 30-gallon airtank. If your current regulator is an orifice type, it may be closed too much to get the pressure you want. (It simply does not have resolution to set low pressure.)

You definitely need to find time to check for leak. If there no leak, you may want to try to get a true diaphram type regulator at the other end of your 1/4" NPT line, near the airbrush. Use the other regulator at the compressor to set pressure down to 50 psi or so. The diaphram type regulator may be able to get you a steady flow at the 15-25 psi you want for the airbrush.  Good luck. 

Keilau, thanks, that makes a lot of sense.  I am using a regulator(s) that are probably more designed to deal with air tools etc.  They are much cheaper than the regulators at the hobby shop, but I guess that is why.  What type/brand do you recommend?  Cost being an issue too.  I really appreciate the help.

Cheers,

Greg

Gregbbear

Keilau, thanks, that makes a lot of sense.  I am using a regulator(s) that are probably more designed to deal with air tools etc.  They are much cheaper than the regulators at the hobby shop, but I guess that is why.  What type/brand do you recommend?  Cost being an issue too.  I really appreciate the help.

Cheers,

Greg

If cost is an issue, try TCPGlobal. They have two models and the difference in price reflects plastic vs. glass dome. The later being the more expensive one at $19 shipped. You can get it at their Ebay store.

If you want name brand one, the Paasche prices theirs the cheapest. Iwata and Badger have good unit too, but are very over priced. You can see them at the Chicago Airbrush Supplies.

I use an TCPGlobal regulator from many years ago and it works quite well for many years. I don't know the quality from other Ebay sellers.