Compressor spray pressure issues

DRHarris61

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Haven't posted here in a long time, but I have a question regarding compressors. The one I have I purchased off of Amazon 2+ years ago with the trio of master Brand airbrushes it came with. Just the diaphragm unit with no tank. I have always been suspect at the accuracy of the regulator, but lately no matter how much I dial 'up' the spraying pressure remains at 20-25psi. I can drop it down, but can't raise it any higher. I have a Badger Patriot 105 which I use primarily all the time, but occasionally the Master AB, too. I've tested it for leaks, but the only sure thing seems to be around the handle mount on the one corner of the cylinder head cover. I've tightened it as much as I dare for fear of breaking the bolt. Should I just replace the unit and figure to do this every couple of years? Can't afford a high quality unit such as a Badger or Iwata and I'm not a prolific-read fast-builder.
 

urumomo

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What exactly is the problem you are having ?

You shouldn't need more pressure ( I rarely go over 14 # ) . Not spraying or spraying poorly can be for MANY reasons .
More info please ;D

... . I don't know the limit of the diaphragm pumps . I assume they must be comparatively low
 

DRHarris61

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Sorry, I forgot to mention that the factory preset on the compressor for the highest PSI before auto shutoff is 60psi. It automatically turns back on at 45psi. I'm only trying to find out if the regulator is faulty, or if the compressor itself is going bad. And there are some mediums which specify a higher psi, such as the Alclad clear gloss coat recommending 20-25psi. My Badger only gets to about 18psi, which is enough, but it should be able to be dialed up higher.
 

urumomo

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So it runs until the gauge indicates 20 - 25 psi ? It shuts off there no matter what ? Or the motor runs and runs but it never produces more than 25 psi ?

You only have one gauge ? Assuming the indicated pressure is correct , the issue is with the pressure switch - otherwise the motor would continue to run since the circuit would remain closed .
There could be an issue on the motor side , but I need more operation info . -
 

DRHarris61

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Yes, there is only one gauge. It's a regulator with a moisture trap at the bottom. When the compressor is turned on, it builds to 60psi, then it shuts off like it's supposed to as pre-set by the manufacturer. If you don't press the trigger on the airbrush, the pressure will slowly drop to 45psi, where the motor starts and the pressure builds again to 60psi. If at any time you begin to use the airbrush,the pressure will drop to between 18 and 25psi, and the motor will continue to run until you stop using the airbrush and the pressure will build again until it reaches 60psi again. This is normal operation. What I am saying is that I cannot adjust the spray pressure to be higher than that 18-25 range despite turning the dial on the regulator clockwise as far as it will turn. I can lessen the pressure by turning the dial counter clockwise. Is it the regulator, or are my airbrushes not able to spray higher than 25psi. Here's a photo of the compressor.

 

urumomo

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OK ,
The pressure switch for the motor control is the line at the left . When it see's 60 psi it shuts the motor off , but as soon as you squeeze the trigger , with no air tank reserve , the volume of air at that pressure vanishes and the 20 -25 psi is all the pump can muster under load . ( the regulator is showing you the outlet pressure that the spring adjustment is set with that juicy 60 psi waiting ;) , but that vanishes fast . What does the manual say it will supply vol/pressure ?
Can you reduce the load . ie the volume . Crank down on the needle travel stop . --- course , you may need both .

Get a little cheapo , pancake compressor from Harbor Freight and one of those air storage tanks too . either 5 or 11 gallons . Some hose and fitting s and you can charge it up and spray away .
I operate an old 3 gallon hooked to an 11 gal reserve tank and it will last me days -- even an all day spray fest ;D
 

DRHarris61

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Thanks, that was the answer/information I was looking for. So basically nothing is really wrong it's just incapable of spraying higher by design and physics.

I have a follow up question. I have been thinking about getting a larger compressor which will allow me to spray with a mini touch up gun for larger projects like the 1/350 Enterprise kits. Any economical recommendations or suggestions. And will these compressors be compatible with airbrushes or are they too powerful? I know I sound like a newbie but I want to get my facts straight before I invest in another piece of equipment.
 

urumomo

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;D ;D heh heh , no compressor is too powerful , over-size maybe , -- the regulator will control the output .
( in the compressor range we're talking about ;) not mondo centrifugal what-nots ) )

You can use any type of compressor you like , as long as you have the proper filtration and pressure regulator .
The ubiquitous filter at the regulator is fine but it's better to have a decent moisture / particulate trap prior to it .

If you use an oil bath compressor you need a filter intended for oil separation . But it's not any huge amount , and if you're operating it in a conditioned space the amount of moisture is fairly moderate . Both easily handled .

Any set-up that has a tank is going to be superior . If you have the space , the bigger the tank the better . or you can hook up storage tanks as I said before .

As far as the little compressors offered specifically for this application , I can't help you . The old Google investigation into warranty and other customer experiences with brands is in order . It's been my experience that the " house-brand " compressors are just as good as the name brands - sometimes better . ( they're often built in the same factory . E.G. Rigid , Ryobi , Milwaukee :p )


Here's the set-up I'm running under my bench -
It's an old , retired 3 gallon that will barely make 120 psi . I have it plumbed in parallel with that 11 gallon reserve .. . and a whole mess of filters , desiccants and regulators ( but after 2 years running like this the amount of particulate ,oil and moisture trapped is BEYOND tiny ;) . That little filter before the regulator on the compressor stops probably 99 % -- the rest of the filters , regulators and desiccants are there because I have issues 8) < nothing will ever make it to the lonely condensate recovery jars > , what can I say - I like to built stuff ) :




All Harbor Freight so super cheap .

I start out with 14 ( maybe it's 14.5 ) gallons @ 120 psi -- it will last me all week or more with moderate use or easily all day and night if I'm freaking out .
So I only need to listen to that loud-az thing run for about 5 min at a time to charge it all back up .

------- I spray only acrylic and at ~ 12 - 15 psi . Higher pressure eats up way more volume ...
 
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