Minor problem with Iwata HP-CH...

[Lt. Z0mBe]

Wise and Sagely Modelers,

I have a minor problem with my beloved Japanese steel Iwata HP-CH. Basically the air valve is sticky; when I press the release down, it doesn't immediately return to a zero point as it should. When it's not in use and I press down on the trigger, the problem seems slightly better. But, when I am a minute or two into a session, the trigger is back to its old tricks, with a two second delay before popping back up to close the air valve. The needle travel is absolutely unaffected, by the way.

I sloshed some AlClad into the trigger opening a year or so ago. I was able to swab it out but the valve mechanism has been acting like this since then.

Here's what I have done in recent weeks:

- Completely broken the brush down with the exception of the teflon bearing.
- Soaked the non-rubber components in denatured alcohol for an hour or so.
- Cleaned the components (all the little fiddly bits and the inside of the body) thoroughly with alcohol until absolutely nothing comes off on a cotton swab or airbrush cleaning brush.
- Allow components to dry and then re-assemble.
- Test, have problem repeat and spout string of profanity.

There's something realy stupid I must be overlooking. Any thoughts on this would be appreciated.

Thanks in Advance,

Kenny

[G-man]

If i properly am understanding your Dilemma , The Rubber ) ring at the base of the trigger shaft that creates the seal between the small chamber housing the valve at the air hose connection has swollen and is not allowing your trigger to pass freely within its grip. I had the same problem with my old brush a while back. I was told just to replace that O ring to fix the problem. I never tested the fix as i upgraded shortly after that anyway.

Apparently it will swell overtime while using solvent based paints and cleaners causing the trigger to stick as you are describing.

Hope this helps
George

[Lt. Z0mBe]

If i properly am understanding your Dilemma , The Rubber ) ring at the base of the trigger shaft that creates the seal between the small chamber housing the valve at the air hose connection has swollen and is not allowing your trigger to pass freely within its grip. I had the same problem with my old brush a while back. I was told just to replace that O ring to fix the problem. I never tested the fix as i upgraded shortly after that anyway.

Apparently it will swell overtime while using solvent based paints and cleaners causing the trigger to stick as you are describing.

Hope this helps
George

That makes perfect sense. Not having another next to it for comparison, I would never know. I just figured everything was supposed to be so snug.

I will see about ordering one from Mr. Grossman.

Kenny

[Dieghigno]

Remove the trigger and lube the oring with a drop of vaseline oil, the one for sewing machine.

If you disassemble the air attachment, you can lube it from below too...

Also, when you plan to not use the airbrush for some days, lube the needle with the same oil, and put it in not all way down, so color will not stick between needle and airbrush body.

[Kylwell]

You need SUPERLUBE©!

It's the wee little tube of trigger lube Iwata sells. Unlike petroleum based light oils it won't attack the rubber O rings. Give Tom Grossman a call, tell'm Robb sent ya.