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Paasche VL airbrush problem


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#1 crowe04

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Posted 09 February 2018 - 07:26 AM

I have two Paasche VL airbrushes, one I have been using for years without any issues, the second was inherited and as I don't know its full history I have given it a complete o/haul. This covered doing a full strip down complete clean and replacing the air valve plunger, springs and o-rings. Both before the o/haul and after, the airbrush is suffering from the same issue, when the air trigger is depressed approximately half way you get full airflow, further pressing of the trigger the airflow reduces to about half or less. I am at a loss to know what the issue is. My original VL airbrush doesn't have this problem, with this one fully depressing the air trigger gives full airflow. I'm running them off a standard storage tank compressor with the pressure reduced to 30psi. Any help would be greatly appreciated.



#2 Fred Jack

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Posted 09 February 2018 - 06:21 PM

Swap each part one at a time with your working airbrush, testing each time until the problem swaps airbrushes, then you will know which part is in need of replacing. If all else fails, you could be dealing with a build up of paint. Soak in paint remover for a few days, or just keep the airbrush as a “hanger Queen” for spare parts.

Edited by Fred Jack, 09 February 2018 - 06:31 PM.


#3 Rick Griewski

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Posted 09 February 2018 - 10:49 PM

Before doing the swap method so you will not find yourself with two non-working brushes...
I recommend revisiting the two areas that impact air control and I am assuming the brush air flow does not drop off because of a leak some where (wipe with soapy water, look for bubbles) First pull up the brush diagram available on the Paache web site.

Remove the air valve assembly (21) from the valve casing (22). No offense meant but confirm that all the parts are correct and they come out in the correct order. The O-ring is flexible, perfect surface and no deformity and the correct size. Then look up into the valve casing and make sure that it is clean. Clean it out all the way up not the brush. Next look at the surface inside casing where the o-ring rides. This must be smooth and look factory good. If the previous owner cleaned it with a wire brush and a heavy hand the air will leak out around the o-ring as it travels or move/deform and block the air. The same will happen if the channel is very dirty. Send the brush back to the mfr for repair of the valve casing if the valve casing is bad.

The next area is the packing nut. Nothing to loose if you pull that and confirm the same things I mentioned above. Reinstall per the mfr instructions including backing the nut out 1/2 turn from a stugg fit.

HTH

Rick

#4 waroff

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Posted 09 February 2018 - 11:08 PM

Try this: remove the hose and unscrew the air valve screw(26) a bit.

https://www.stds.fr/...vls-2012-fm.pdf


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#5 crowe04

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Posted 10 February 2018 - 12:16 AM

Many thanks to the suggested remedies, re swapping parts out from the operating airbrush to the problem airbrush, yes I had a go at that and the issue remained. In answer to Rick Griewski's suggestions, a thorough check for leaks was done and no sign of any, the air valve parts are all correct and installed in the correct order (no offense taken at all Rick, in fact it is a logical troubleshooting process), the casing is totally clear and smooth and free of any visible defects, a new o-ring has been installed and the whole unit reassembled as per the Paasche diagram. My next step is to try replacing the "old" air valve assembly with the "new" modified air valve, will see how that goes when the new air valve assembly arrives.

 

Try this: remove the hose and unscrew the air valve screw(26) a bit.

https://www.stds.fr/...vls-2012-fm.pdf


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#6 quang

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Posted 10 February 2018 - 12:34 AM

Apparently your problem lies in part 23. It may be bent or distorted and calls for a replacement.
HTH
Quang

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#7 crowe04

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Posted 13 February 2018 - 04:47 AM

Problem solved, new modified air valve and trigger assembly fitted and it all works perfectly, mind you the o-ring that came with the new valve was too small (even though it was shown to be the correct one) I used a slightly larger o-ring that would normally be used on the old style valve and all is good.
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#8 Rick Griewski

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Posted 14 February 2018 - 06:16 PM

Woo Hooo! Congratulations. Happy painting.

Rick




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