Airbrush Problem-button Stuck In Down

[Allan]

Hi fellows,
Has this ever happened to you? I quite like this airbrush, but lately the air/paint button has been sticking in down mode and so air constantly comes out even when I'm not touching the thing. In the photo the compressor is switched on and air is coming out and I don't know how to stop it. Paint will come out when I pull the button back of course, but when I stop the paint flow the air continues to come out of the nozzzle.
I'm tearing my hair out in frustration and don't have much left.
HELP! It seem like a lack of lubrication is the cause, but I'm not sure.

Sorry the photo is on its side-don't know what happened.
Allan in Canberra

[Hobbes]

It could be because thinner got into the air valve and has ruined the rubber seal inside the valve (the local airbrush specialist told me never to get solvents into the air valve, because of this).

Have you disassembled the airbrush yet?  

[RotorheadTX]

You'll need to take it apart to investigate. I also suspect that the sealing o-ring is leaking, but it might also be a mechanical failure. I have a Paasche single-action H-type that recently needed it's air valve replaced because the return spring had gouged the sides of the air plunger, causing it to hang.

[Supertom]

Looks like the air valve is bad.  It's a part you can replace though.  What brand of airbrush do you have?  I know the Badgers were prone to losing the air valves.

[Excalibur]

Its possible that the trigger has been stuck to the valve by paint. Hopefully all it needs is a good clean. Especially focusing on the trigger & surrounding areas. It's a good first step anyway, dismantle the airbrush & clean everything really well.  

[matrixone]

Allan,

I think what Hobbes said is right, the rubber seal may have been damaged. Or (if you are lucky)it could just be some dried paint had gotten into a place it should not have and gummed things up. The only way to know is to strip it down and clean it and try it again.

Matrixone

[Allan]

Thanks for the hints fellows. I'll take it apart and have a look and also ask the fellow who sells similar brushes at our monthly hobby club meeting.
Allan in Canberra

[cthulhu77]

One thing to do when you buy an airbrush:  buy the o-rings and a spare needle or two at the same time...you are going to need them!
   Good luck with the cleaning, just do it over a white paper towel, and keep an eye out for little springy parts!

[Allan]

I tend to think the cause is mechanical because even before I actually used the airbrush the button sometimes stiuck in down mode.

I'll have Peter take a look at it on Wednesday evening.

Allan in Cnaberra

[van883]

Hi Allan
I have special lube oil (!) designed for airbrushes-the instructions for the Iwata I have specifically talk about lubricating the needle and lever mechanism periodically.

Van

[Allan]

Van,

I think you have perfectly hit the nail on the head--it's a lubrication problem it seems to me too.

I'll keep you posted re this.

Allan in Canberra

UPDATE: Peter's told me over the phone that the O rings needs a little Vaseline and will show me how to apply it tomorrow evening.

[Allan]

Yup the airbrush was fixed by a dab or two of vaseline on the trigger mechanism and the O ring applied with a toothpick and small brush.
I've heard of some blokes even using chap stick as lubrication!
Anyway, thanks for all your suggestions.
Allan in Canberra