Sticky SMS airbrush

[stillp]

As a newcomer to airbrushing, I've been very pleased with the cheap Scale Model Shop airbrush I bought, but it's playing up today. When I release the button it doesn't shut off immediately - if I give it a nudge to the off position it shuts off OK, otherwise it takes a couple of seconds. I've stripped it down and cleaned everything but the problem is still there. Does anyone have any ideas? Does the needle need any lubrication?

Pete

[col68]

It wouldn't hurt to oil the needle and trigger peter also check that paint hasn't built up in the tip as it can stop the needle from returning properly.

[Guest]

Which model is it?

[stillp]

Thanks Col, I tried a small drop of oil, which made no difference. The tip has had a soak in airbrush cleaner and a go with a reamer.

John, it's a Model (well, they say MODEI!) BD. I'm wondering if the o-ring for the needle guide might have swollen.

Pete

[Guest]

I'd say dried paint somewhere along the needle, or in the end of the nozzle are likely culprits (ask me how I know?!). Go easy on that reamer, softly softly, those nozzles are dead easy to split.

[stillp]

The needle has been out and cleaned several times John. Thanks for the advice about the nozzle, I've been gentle with it so far.

Pete

[Guest]

Do you use a lid on the paint cup? If so, be sure that the little vent hole is completely clear.

[Guest]

If it's the air plunger that's not popping up snappily odds are the rubber o ring around the air inlet has slightly swollen, remove the needle and pop the trigger out, clean and lubricate the lower part of the plunger and refit.

[Guest]

My H&S airbrush did that once when both it and I was new at airbrushing and it was because I'd attempted to spray a too think primer without thinner through a 0.2 nozzle. Some kind of issue then happened when I tried back flushing to solve the problem, but instead caused primer to end up all the way back in the handle, the piece that you're holding. On the way back some paint managed to get stuck on the trigger mechanism which made it wonky.

Lesson learned - don't back flush a H&S airbrush when it's jammed with too thick primer.

It's easy to remove the trigger on most airbrushes. On mine I just unscrew everything on the rear end and out comes the whole mechanism. To assemble just do everything in reverse.

It sounds like you've tested everything that has to do with normal operation so perhaps you've got some paint inside the mechanism and handle like I did?

[Guest]

I thoroughly stripped and cleaned my H&S Ultra yesterday, and was surprised how the tiniest deposit on any of the components leads to airbrushing hell! Using Tamiya yellow cap thinners on a cotton bud revealed some visible stains (that X20a thinners did not) on what looked to be a squeaky clean needle. Also, I very carefull reamed the nozzle which revealed some almost microscopic particles on the edge of the reamer. I did all of this as I wasn't happy with the shape of the spray pattern, when spraying water through it. Once his had been done, it all worked fine. On a side note, where do folks stand on Super lube? I have a concern about oil polluting the paint and preventing it from adhering to the surface, but maybe I worry too much!

[John]

Nearly a year use out of it and not needed to change the needle and nozzle is good, if you remove the bit the hose connects to does the pin push in without sticking?

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[John]

If it does you can remove it and clean it, you will see 2 small holes, you will need to get something in them to unscrew it.

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[Steve Brodie]

I had a similiar problem when i first used my Iwata Eclipse, first time out of box and did the same, now i knew it wasnt likely to be the airbrush as having been checked before it left the factory, BUT didnt stop me stripping it down and putting back together, only to still be doing the same, put old airbrush back on and no issues. Time to put my expensive Kepner Tregoe ( http://www.kepner-tregoe.com/about-kt/) Problem theology to work ; what has changed or is different. So the only thing i added in the chain between airbrush and compressor was a quick release valve - surely, that cant be it - removed valve and after a couple of clicks on the trigger - problem gone. Dunno why the quick release valve works okay on the chepo brush, but it does.

[Guest]

My H&S airbrush did that once when both it and I was new at airbrushing and it was because I'd attempted to spray a too think primer without thinner through a 0.2 nozzle. Some kind of issue then happened when I tried back flushing to solve the problem, but instead caused primer to end up all the way back in the handle, the piece that you're holding. On the way back some paint managed to get stuck on the trigger mechanism which made it wonky.

Lesson learned - don't back flush a H&S airbrush when it's jammed with too thick primer.

It's easy to remove the trigger on most airbrushes. On mine I just unscrew everything on the rear end and out comes the whole mechanism. To assemble just do everything in reverse.

It sounds like you've tested everything that has to do with normal operation so perhaps you've got some paint inside the mechanism and handle like I did?

It happened once with my Iwata Hi Line HPCH, so even the high end stuff do get affected. Same problem. Backflowed it. I simply just cleaned it out thoroughly and then lubed it and then it worked no problems.

[Guest]

If it does you can remove it and clean it, you will see 2 small holes, you will need to get something in them to unscrew it.

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I always use a tweezer which is strong, slot it in the two holes, and sliding my hand to the front of the tweezers, unscrew that plate off if I need to