Lack of pressure once the nozzle cap is screwed on

Franc Kaiser

Air-Valve Autobot!
I am experiencing a real problem with my brush.

I got a brand-new Sparmax Sp-20x (0.2mm). For the first 1 - 2 hours it worked very well, although I am using a small mini diaphragm compressor (the ones you typically use for nail art, etc... yes, I know that I need a real compressor very soon!!!) which is pulsing at reducing rates, typically. I am using Golden High Flow acrylics, sometimes reduced with some water drops.

My big problem now: The airbrush appears to receive no air (or not enough air pressure) once I screw on the nozzle cap on top of the nozzle. If I run air through the brush without the nozzle cap on, it feels and looks like it receives plenty of pressure (it must be between 10 – 20 psi). If I screw on the nozzle cap, the pressure reduces audible to almost nothing. To avoid misunderstanding what I mean with the nozzle cap, I am attaching the breakdown of the brush, with the “nozzle cap” highlighted.

I checked and cleaned the nozzle cap continuously. I deep cleaned the whole entire rest of the brush. The problem persists, and makes painting virtually impossible… I don’t have any air power in that device that sucks and sprays the paint as it should.

What is going wrong here? Is it an issue if the small diaphragm compressor, and would a better compressor (at higher psi) solve the issue? Or do I need to be worried about the air valve?

Any thoughts and experience is highly appreciated. I may overlook something elemental. This forum has become my only sounding board for airbrushing issues… I don’t have other people that I can ask those questions, and I find you guys so communicative and willing to share that I already want to buy them a few cold beers :)

SP20xProblemsmall.jpg
 
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My .2 mm needle did this to me and it turned out that the nozzle you highlighted in your diagram was plugged with paint . I used a toothpick and cleaned it out and it worked like new. Not saying this is your problem but if the gun is pushing air without that lid on it certainly seems to me that, that is the culprit :) Good luck!
 
My .2 mm needle did this to me and it turned out that the nozzle you highlighted in your diagram was plugged with paint . I used a toothpick and cleaned it out and it worked like new. Not saying this is your problem but if the gun is pushing air without that lid on it certainly seems to me that, that is the culprit :) Good luck!
Thanks Samantha... I had the same thought. I soaked the cap with cleaner, cleaned it out.... it could not be cleaner. The problem still persists... almost as if the cap whole is too small (which it is not... the needle goes through well).
 
What is going wrong here? Is it an issue if the small diaphragm compressor, and would a better compressor (at higher psi) solve the issue? Or do I need to be worried about the air valve?

Sorry I don't have any other troubleshooting for you. you said it worked fine for 2 hours? is the compressor dying? I really don't have any other answers for you Franc =/ Hope you get it sorted.
 
There should be little holes in that cap, are you sure they're clean? Someone on here the other day discovered that those holes were plugged. Try holding the cap up to light and see if you can see light thru each hole. Other than that, I'm stumped!
 
There should be little holes in that cap, are you sure they're clean? Someone on here the other day discovered that those holes were plugged. Try holding the cap up to light and see if you can see light thru each hole. Other than that, I'm stumped!
Jurien72, I am only aware of one hole in the nozzle cap... the one that threads the needle and is just before the nozzle. Am i overlooking something? Are there more holes in that cap?
 
Jurien72, I am only aware of one hole in the nozzle cap... the one that threads the needle and is just before the nozzle. Am i overlooking something? Are there more holes in that cap?
Can you push your needle in to the nozzle? Take you needle and try gently to push it in to the nozzle, to see if it will come out. If not, your nozzle is full of crap.

edit: push 25 in to 3
 
Jurien72, I am only aware of one hole in the nozzle cap... the one that threads the needle and is just before the nozzle. Am i overlooking something? Are there more holes in that cap?
There should be other holes in the aircap that allow air through. Maybe take a really close look at the front end of the cap and check there is something to allow air through and around the nozzle. I’ll try and find a photo of something similar.


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This is from an Eclipse CS. I think it’s called a head cap. But you can see one of the holes in the top right. The nozzle would poke through the centre of this and the holes allow the air through so that it can pull the paint.
Apologies if you know this already.
542b1f9e4610ba8c9eb3f9d0bd9321c9.jpg



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This is from an Eclipse CS. I think it’s called a head cap. But you can see one of the holes in the top right. The nozzle would poke through the centre of this and the holes allow the air through so that it can pull the paint.
Apologies if you know this already.
542b1f9e4610ba8c9eb3f9d0bd9321c9.jpg



Sent from my iPhone using Tapatalk

Hi SiRoxx, many thanks for taking the trouble and researching on this issue (and finding a picture). However, the picture of the air cap does not correspond with the air cap that the Sparmax Sp-20x is using. Maybe most people call it actually the "tip" - if my lingo has been misleading, then I apologize for that. I am attaching the actual picture of the air cap (or tip) of the Sp-20x: No holes found there (at least not on the outside). The air holes are in the part where the nozzle is screwed on top... in case of the Sp-20x, that part cannot be removed.
 

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  • nozzlecap_sp20x.jpg
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What does it look like from the bottom? I also wonder if you arent getting a seal somewhere. Try putting the head of the AB under water and hit the air... see if bubbles come from somewhere they shouldn't? *Be careful don't give yourself an unwanted shower*
 
Hi SiRoxx, many thanks for taking the trouble and researching on this issue (and finding a picture). However, the picture of the air cap does not correspond with the air cap that the Sparmax Sp-20x is using. Maybe most people call it actually the "tip" - if my lingo has been misleading, then I apologize for that. I am attaching the actual picture of the air cap (or tip) of the Sp-20x: No holes found there (at least not on the outside). The air holes are in the part where the nozzle is screwed on top... in case of the Sp-20x, that part cannot be removed.
No need for apologies Mate, you didn’t have the wording wrong, manufacturers use different terms for things too. I was just trying to find a simple photo to show the holes that the others were referring to and you have it spot on. It would be the piece that the nozzle screws into. If those holes are clear, then we can eliminate that as a cause. I suspect they are as you already said that the air flows until you screw the cap on. If the hole on that cap is clear, we need to think again.


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It is like all the Iwata guns (except Eclipse) and only has the one hole where the nozzle pokes through. Because it does not need to hold the nozzle in place, it does not need a center ring with holes around it.

HP-crhead.jpg
 
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No need for apologies Mate, you didn’t have the wording wrong, manufacturers use different terms for things too. I was just trying to find a simple photo to show the holes that the others were referring to and you have it spot on. It would be the piece that the nozzle screws into. If those holes are clear, then we can eliminate that as a cause. I suspect they are as you already said that the air flows until you screw the cap on. If the hole on that cap is clear, we need to think again.


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By logic of elimination and
No need for apologies Mate, you didn’t have the wording wrong, manufacturers use different terms for things too. I was just trying to find a simple photo to show the holes that the others were referring to and you have it spot on. It would be the piece that the nozzle screws into. If those holes are clear, then we can eliminate that as a cause. I suspect they are as you already said that the air flows until you screw the cap on. If the hole on that cap is clear, we need to think again.


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By logic of elimination of possible causes, I start to conclude that it must be lack of air pressure and that a better (non-pulsating, really performing) compressor. I will need to buy one anyway. Hopefully my dear Sparmax will comply accordingly...
 
By logic of elimination and


By logic of elimination of possible causes, I start to conclude that it must be lack of air pressure and that a better (non-pulsating, really performing) compressor. I will need to buy one anyway. Hopefully my dear Sparmax will comply accordingly...
It is often the simplest solution that turns out to be correct. But that’s part of learning, it’s as much what to do when things aren’t going right as what to do in the first place LOL. This has allowed you to get pretty familiar with the inner workings of your airbrush. That will pay off in the long run as they’re all fairly similar.


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It is often the simplest solution that turns out to be correct. But that’s part of learning, it’s as much what to do when things aren’t going right as what to do in the first place LOL. This has allowed you to get pretty familiar with the inner workings of your airbrush. That will pay off in the long run as they’re all fairly similar.


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Agree... the start of a beautiful love/hate friendship. Hopefully more love than hate. However, I do learn that taking the cheap route brings a lot of confusion and frustration. There are indeed high entry barriers to this passion. Maybe that's also part of its charme.
 
We’re all familiar with the frustration airbrushing can bring. But that makes the wins much more satisfying. The kit can help, but the pricy brushes can have their own pitfalls too. I’ve seen wok here from a member who was asked to do a demonstration piece at a college. They supplied a cheap brush, unfamiliar paints and the work was incredible. The benefit I found through a higher quality brush is that I spent less time wondering if there was a mechanical issue. when things weren’t going right, at least I knew it was me, general technique or reduction lol.


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back off the cap a little bit at a time and see if your air starts coming thru?it might be its on to tight and is interfearing with the air flow to the tip? also check and see if the nozzle is screwed on all the way if not it would block the hole in the cap too!
 
Sorry for being lazy and not reading through the whole post. Did you by any chance change the nozzle or nozzle cap with a different brush. If the nozzle is too large it will close up the hole in the nozzle cap. And the same goes if the nozzle cap is for a smaller nozzle set up. I did this once with my Paasche VL 3 set up with the three interchangeable head system.


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