Airbrush pressure dies

[Evan Parra FX]

Hey forum! I have a weird problem that I can't figure out. It's probably something so simple too. I work with an Iwata Hi-line hp-ch and it's been phenomenal. I ordered an Iwata Eclipse hp-cs as a backup. I hooked up the Eclipse to my compressor and it will blast air out and then immediately the pressure will fade to where even water won't spray.

The Hi-line works just fine though and distributes nice even pressure, so I assume it can't be the compressor. Both airbrushes are using the same hose, so no difference there. The needle on the Hi-line is .3mm and the Eclipse is .35mm so not much difference there either. I can't figure out what is causing the Eclipse to blast out air and then immediately fade out to almost 5 psi working pressure.

Any thoughts?

 

[Rick Martin]

Regulator leaking?

 

[Evan Parra FX]

Hey Rick! Not that I'm aware. Even if it was leaking, I would assume I'd have the same problem with the Hi-line. But that airbrush works just fine.

 

[Rick Martin]

Thwn i would check the orings in the air valve.

 

[DaveG]

I suspect the o-ring in the air valve, sometimes the do roll out of place... But, what kind of compressor, and about what pressure are you using? Do you have a moisture filter attached to your brush?

 

[JackEb]

Have you had paint through the Eclipse yet, if so it could be a bit of gunk closing off the air flow, if its a virgin brush then I’d go with Dave’s diagnosis.

It would also be appreciated if you went and introduced yourself in the apppropriate section.
Let us know where you call home, what paint etc you currently use and it’s nice to know what you like to paint too eg: art/T-shirt’s/RC

We’re a nosy bunch but it also helps us get to know you better

 

[Evan Parra FX]

Thanks guys for the replies. I was messing with the airbrush and added some lube before I have to disassemble the air valve. Still same problem, but seems a tad bit better. You might be right about the o-rings. I'll dismantle this sucker in a bit and see what's going on in there. Yeah Jack, no paint has even gone through it yet. That's why it's so frustrating. So frustrating that I've lost my good manners and didn't properly introduce myself. Haha! I'm a special fx artist and mask/props maker in Austin, TX. I appreciate the help.

Dave, I'm using a cheapo Master air compressor tc-20t. It has a tank and has been problem-free for a few years now. The pressure is at 40. I usually turn it down a bit using the MAC valve on the Hi-line. There's a moisture trap on the compressor, not on the brush.

 

[DaveG]

Dave, I'm using a cheapo Master air compressor tc-20t. It has a tank and has been problem-free for a few years now. The pressure is at 40. I usually turn it down a bit using the MAC valve on the Hi-line. There's a moisture trap on the compressor, not on the brush.

No problem, just wanted to make sure the compressor had a tank, the Eclipse will push more air than the Hi-Line. The reason I asked about the moisture trap is that some of them have an o-ring in in the connector that will squish enough to block off air flow if they are tightened too much.

The brush is actually fairly simple. Air enters where the hose connects and travels forward through the brush once it is allowed to pass the air valve. To make sure there is no debris in the brush body itself, I would remove the nozzle cap - and depress the trigger to blast the air. The only other place there can even be an issue is with the air valve itself, and that will be the O-ring. It should be seated against the brass shelf on the stem. Sometimes the roll up out of place, and will block air flow into the brush body... There is another thread going on right now about "diagnosing issue with eclipse" that has some inks and photo's that will help get you into the air valve.

 

[Evan Parra FX]

Okay, I took the air valve apart, inspected everything, and the o-ring was on there tight and sturdy. Seemed like it wasn't the o-ring at all. Very strange! I put everything back together and figured maybe I'll just return it and exchange it for another Eclipse or get a different airbrush. I fired up the compressor to test it one last time before I send it back... and it works fine now! It's holding a nice consistent pressure like the Hi-line and even the trigger feels... buttery. I'm guessing maybe the air valve nut wasn't screwed in all the way perhaps. It was pretty easy to screw off with not much resistance at all. Very, very odd. But hey, it works!

Thanks guys for everything! And that thread about dismantling the air valve really helped a lot. I appreciate it!

 

[JackEb]

We generally recommend that even new brushes are stripped down, cleaned of any manufacturing junk and reassembled.
Your result shows that sometimes it actually helps.
Even though yours was fairly loose, a similar symptom can been seen if it’s overtight, the oring squashes and intrudes into the airflow. Because of the high pressure on first press it will initially flow, once it’s flowing a bit gentler the oring can once again intrude.

 

[Malky]

This is a long shot, but since no one has mentioned it, I will, have you checked the rubber seal that sits in the inside of your quick connect bayonet attached to the brush, if the bayonet is on too tight the rubber seal will swell and also starve you of air, ive had this a couple of times but in my case it was due to a faulty rubber in in the bayonet.

 

[Evan Parra FX]

Hey Malky! Yeah the quick connect was fine and the seal was in place. I even tried hooking the hose directly to the airbrush and was still having the same problem. It turns out the air valve was just loose and the bottom nut needed to be tightened. Everything is working fine now.

 

[Airbrush Dreams]

Hey Malky! Yeah the quick connect was fine and the seal was in place. I even tried hooking the hose directly to the airbrush and was still having the same problem. It turns out the air valve was just loose and the bottom nut needed to be tightened. Everything is working fine now.

Check the hole in the rubber gasket of the quick connect. I had one that the hole was slightly off center and when tight it would pinch off the air. While not spraying the air would build back pressure and then as you would push the trigger that air would blast away till it was released and then I wouldn’t get enough pressure.


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