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Need help with airbrushing

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  • Member since
    February 2020
  • From: Virginia
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Need help with airbrushing
Posted by nubbin3642 on Friday, February 21, 2020 1:09 PM

I am new to airbrushing and need advice.  I have a Testors Mini Blue compressor and a Badger internal mix single action airbrush using a siphon cup.  I am trying to repaint and detail a couple of box cars  to learn but I can't seem to get the hang of the air pressure.  The miniblue says it puts out 40 psi.  I have a pressure-regulator in the mix, and set it to 28, but every time I press the trigger the pressure drops to about 10 with a low paint flow.  I've checked and rechecked for leaks at the hose joints to no avail.  Any suggestions for me?

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Posted by mlehman on Friday, February 21, 2020 5:05 PM

What kind of paint are you using? That's opften something different from the rather generic instruction that might come with an airbrush or compressor.

While many small hobby compressors are intended to work "on demand" it's to your advantage if there's a storage tank of some kind. This helps the compressor keep up and provides a steadier flow.

It soundslike you may be drawing too much air when you start using the brush, so the PSI drops sharply when it engages. Check to see if you can adjust that demand downward to compensate.

Mike Lehman

Urbana, IL

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  • From: Canada, eh?
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Posted by doctorwayne on Friday, February 21, 2020 5:11 PM

Welcome to the Model Railroader Forums!

I'm not familiar with either the compressor or Badger airbrushes, but I'm curious as to the paint you're using, as 28psi is fairly high for painting models, especially if you're using acrylics.  Most paint manufacturers recommend between 15-20 psi.

Does the compressor have an air tank, or does it run continuously?  How long are you holding the trigger down?  Usual practice is to press down before beginning a pass over the item being painted, and release the trigger once the pass has been completed - you can make consecutive passes back and forth, but usually with a short pause between each pass.

Hopefully someone more familiar with that equipment will join in.

Because your first few posts are moderated, be patient for your chance to reply.

Wayne

 

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Posted by dbduck on Friday, February 21, 2020 5:57 PM

not familiar with either compressor nor airbrush (i use Paasche)  but in my opinion if the pressure drops to 10 pounds when the trigger is pressed..that is your actual "painting" pressure.  adjust the regulator to the desired pressure while  holding down the trigger

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Posted by BigDaddy on Friday, February 21, 2020 6:27 PM

There are 8 amazon reviews and 2/8 complained of low or no output.  There is a 12 yo thread of Fine Scale modeler and that maybe too old to be relevant, but one reviewer said it was only good for water colors. 

It's expensive, the same price there as my Porter Cable with 6 gal tank, and I found prices 35% higher than that.  If it has a reservoir, it must be small.

You didn't tell us what paint you are using.  Some paints are airbrush ready other paints need thinned by 40%

I doubt the accuracy of any of the compressor gauges, but a 30% drop in pressure is significant.  I guess I shoot at higher pressures than Dr Wayne, 20-25. 

Henry

COB Potomac & Northern

Shenandoah Valley

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  • From: Ontario Canada
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Posted by Mark R. on Friday, February 21, 2020 6:53 PM

With the airbrush "off", the gauge is reading the back pressure. When the trigger is depressed, the gauge is reading the continuous flow pressure. You need to adjust the regulator with the trigger depressed. Those little compressors aren't capable of providing a huge amount of continuous air flow, but any compressor will build a substantial back pressure. If you want to spray with 30psi, your compressor needs to be capable of supplying that kind of air flow continuously.

(Edit) - One review I found on that mini blue compressor ....

"The Testors compressor puffs air, it's not a constant flow. It's constant at about 15psi, but it puffs bursts of 30-35psi. It's so weak it doesn't even pick up the paint in my siphon cup"

 

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

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Posted by mbinsewi on Friday, February 21, 2020 8:17 PM

I'm not an air brush professional, by any means, but I agree with Mark and dbduck as far as the actual pressure, and Mike's idea of a supply tank is also good.

Mike.

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    January 2004
  • From: Canada, eh?
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Posted by doctorwayne on Friday, February 21, 2020 8:23 PM

BigDaddy
I guess I shoot at higher pressures than Dr Wayne, 20-25.

Yeah, I goofed as mine should have read 20-25, too.  My compressor doesn't have a tank either, so it runs constantly, but with a very even air supply, as it's a rotary-type - two screws running in an oil bath. 

Wayne

  • Member since
    February 2017
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Posted by Deane Johnson on Friday, February 21, 2020 9:23 PM

In doing a little surfing around, I came away with a couple of impressions.  It's grossly overpriced, and it doesn't have much fire power.  One guy who owned want commented that in his usage, it dropped to 10 psi while painting.  He commented that it's rated at 35 psi, but he could never get his over 24 psi.  Multiple users rated it poorly, some called it "junk".

No way to tell if there is something not set right on the OPs unit or not.  It seems to me even a unit like this shouldn't drop more than 3 or 4 lbs during use.  Just a guess.

 

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Posted by jjdamnit on Saturday, February 22, 2020 11:53 AM

Hello All,

I made this reply...

"Hello all,

Yes, I bought the Airbrush Compressor with Airbrush Kit (#95630).

I have been using rattle cans for all of my hobby painting needs. I saw this item in the HF flyer.

The price was right at $79.99; including the airbrush with accessories.

I got home, unpacked it and assembled the kit. 

The first thing I noticed was that the "regulator" on the compressor (attached to the moisture trap) is not a regulator. It is just a P.S.I. gage.

When I activated the airbrush the gage only monitored the P.S.I. of the flow to the airbrush. It dipped and climbed with the release of air through the airbrush.  

There is a knurled knob on the bottom of the moisture trap that acts as somewhat of a regulator.

Air was leaking from this knurled knob assembly. I pulled it apart to discover that one of the O-rings had been crushed during assembly.

I called HF customer service and they could not provide a replacement part for the damaged one. They told me to return it to the place of purchase for a replacement.

The only problem is that the nearest HF; where I purchased this kit, is an hour-and-a-half away- -one way!

I went to the LHS; 6-miles away, and found the replacement O-ring for less than $1.00!

The unit worked but there was no true pressure regulation.

For $20.00 I purchased a true pressure regulator, an adapter nipple and sealing compound.

I installed the pressure regulator, reassembled the kit and everything is now working just fine.

The airbrush itself is not the highest quality for really fine lines, but for my general needs it does the trick.

The bottom line:

Yes, it did take additional time, effort, parts and money to bring this kit up to a reasonable working order.

The actual compressor is quiet and does reach the 58 P.S.I. listed, once the O-ring issue was solved.

The airbrush is an inexpensive model that I will eventually "upgrade".

I'm a tinkerer so "customizing" this kit was not a deal-breaker for me, but might be the deciding factor for others.

Would I recommend this kit to a friend I would say, "Yes, with caveats!"

Hope this helps.

Post Script:

Micro-Mark offers what appears to be the identical compressor (#86108) for $99.95. A separate regulator/moisture trap (#86113) for $27.95. This does not include fittings, an airbrush, hose and other accessories.

HTH- -J.J.D."

In this thread...

Harbor Freight Air Compressor

Hope this helps.

 

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by snjroy on Sunday, February 23, 2020 6:36 PM

It would be good to know what type of paint is being used. Paint thickness can be a factor as well.

Simon

  • Member since
    December 2015
  • From: Shenandoah Valley
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Posted by BigDaddy on Sunday, February 23, 2020 7:05 PM

That was the OP's 1st post so we will have to wait till Monday for answers.

Henry

COB Potomac & Northern

Shenandoah Valley

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