Airbrush problems

[csavaglio]

Lacquer thinner's pretty harsh....no guarantees it won't kill the o-rings, although, only soaking it for a few minutes shouldn't. But it does work the best by far.

 

If you use Simple Green, you really have to mke sure you clean it with a ton of water to get it all out. Run it through the ultrasonic cleaner a few times in fresh water each time, then run it under running water. Even a little SG residue will make your paint to funky stuff.....ask me how I know....

 

Chris

[cyarborough]

I have soaked my c+ for days in laquer thinner. Have been doing it for about a year with no issues. The c+ has no exposed o-rings. I think that is why It costs more than the c.

[RandyB]

Lacquer thinner's pretty harsh....no guarantees it won't kill the o-rings, although, only soaking it for a few minutes shouldn't. But it does work the best by far.

 

If you use Simple Green, you really have to mke sure you clean it with a ton of water to get it all out. Run it through the ultrasonic cleaner a few times in fresh water each time, then run it under running water. Even a little SG residue will make your paint to funky stuff.....ask me how I know....

 

Chris

 

 

I have soaked my c+ for days in laquer thinner. Have been doing it for about a year with no issues. The c+ has no exposed o-rings. I think that is why It costs more than the c.

 

Thanks gents, good points to consider. Once I get the ultrasonic cleaner, I'll be sure to play around a bit...

 

Sorry for hijakin' your thread Kev!

[LSP_Matt]

I noticed at an expo last year that small ultrasonic cleaners have got substantially cheaper. Apparently its not a super idea to have flammable liquids in them though. If you're keen I can look them up and see what we could get them for. I'll have a scrounge tomorrow for some interproximal toothbrushes...they might really work nicely

 

Kev...I went to the chemist and purchased a jar of Dermeze which is non-petroleum based. It seems fine and lubes the needle nicely. I did have some of the Iwata lube but the packaging was crud and it leaked all over the place...IIRC it was also very expensive for such a small amount. I have the HP Plus BP Iwata.

 

Cheers Matty

[csavaglio]

I have never tried leaving any airbrush soaking for more than a few min, so I can't say good or bad on it.

 

The difference between the HP-C and HP-C+ has nothing to do with the O rings or any other major design element. the only difference is the thread pitch on the nozzle to body. Iwata had complaints that folks were stripping them out by over torquing them and so they came out with the plus series with a more coarse thread to help.

 

I'm not even sure if you can still get many non plus models. Most of the new stuff like the HP-CH only exist with the plus thread pitch.

 

Chris

[cyarborough]

Does the C have Teflon needle packing?

 

I also discovered that there is an o-ring in the air valve. I have never pulled the air valve off for cleaning. So...I pulled it off last night to check that o-ring and it was in perfect condition. I think the fit of the air valve to the body is such that liquid cannot reach it.

[automaton]

Personally, I think that the less tearing down you can do, the better. No need to put unneccesary wear and tear on the threads of the nozzle, etc., as brass is a pretty soft material. My workhorse is an Iwata HP-CS, which I use for everything but the most delicate applications. It goes many months without being dismantled any farther than removing the needle, and almost never gives me any kind of trouble.

 

Earlier in my modeling life, I was constantly frustrated by airbrush "incidents" (clogging, spitting at the most inopportune moments, inconsistent spray, etc.) I still have many frustrations in modeling, but very rarely have any issues with airbrushing. I think that's mostly down to the fact that I've found an airbrush cleaning regimen that consistently works for me with any paint medium I use, including acrylic, enamels (occasionally), and automotive (rarely):

 

1. Pour any unused paint out of the color cup

2. Wipe out the color cup with a dry piece of paper towel

3. Pour color cup about 1/3 full with generic automotive lacquer thinner

4. Spray about half of this thinner thru, then use a cheap nylon-bristled

children's art brush to "scrub" in the bottom of the cup around the needle

5. Spray the rest of this thinner out while it's still agitated into a solution

6. Pour another small amount of thinner into cup, spray a part of it thru, then

withdraw needle just far enough that it doesn't show in bottom of cup (important:

keep airbrush tilted downward about 45 degrees at this point to prevent thinner

from possibly running back past packing into body of airbrush)

7. (Airbrush is still tilted at 45 degrees here) Run a conical intradental brush thru

color cup toward tip, gently pushing it in as far as it will go (this will actually

"squirt" a small amount of thinner out the end of the nozzle)

8. Push needle back to home position and re-tighten needle locknut

9. Spray remainder of thinner out, wipe any remaining color residue

from the top of the cup with a thinner-moistened paper towel, and you're good to go

 

This whole process takes about 40 seconds, and is more than sufficient for color changes. At the end of the painting day, I add two steps . . .

 

10.Remove the needle, wipe it with thinner, lubricate with Iwata lube and reinstall.

11.Use the nylon art brush with auto lacquer thinner to clean the outside of the nozzle

 

I don't worry too much about the outside of the airbrush being clean. I occasionally wipe it off with lacquer thinner when it gets really bad.

 

 

Regards;

 

Automaton

[csavaglio]

I don't believe the original HP-C had the teflon packing in it. It's been so long since I've seen a regular HP-C that it's even hard to find specs. When I bought my C+, they were relatively new and the standards were already being phased out. That would've been 8 or 9 years ago now.

 

I think the O-rings in the Iwata brushes are designed to be pretty resistant to the typical paint solvents, so I wouldn't worry too much about it. O-rings are cheap to replace even if one does get damaged.

 

I'm pretty sure the solvent gets down into the air valve, but hooking it up to your compressor and blowing air through will have the lacquer thinner gone and dry in a second or two.

 

I don't really agree with Automaton about not tearing down Iwatas to clean them. I agree it's not how it should be done every day and my routine cleaning between colors and after spraying is just about the same as his, but that doesn't do enough to keep paint from building up in the crevices of the body and the nozzle. As long as you're doing it properly and not over torquing things, you're not going to wear out the components unscrewing and screwing them back in.

 

Also, keep in mind the HP-CS and HP-C are totally different airbrushes with completely different nozzle designs and sizes. My workhorse brushes are both HP-CS's...one is stock with the .35mm needle, the other is converted to .5mm for biger stuff. The HP-C uses a .3mm screw in nozzle instead of the Eclipse's (CS) drop in nozzle. While it doesn't sound like much, combine it with the difference in needle taper, and it makes a big difference on how it will act when it gets a little dirty.

 

Granted, this all depends on what type of paint is used. I have one airbrush that sprays nothing but Alclad and it hardly ever has to be torn down.

Edited March 31, 2011 by csavaglio

[DrDave]

Can I air a problem too? My Iwata Tr1 sprays windex, acrylics and future fine, but at all pressures it will not spray alclad for more than a couple of squirts and lacquer thinner will not spray through it either. I used to spray lacquer thinner thru as the final clean. I wondered if it was high pressures evaporating the solvent, but I have tried low pressures. Its a pain cos I do my engines and metalwork in Alclad.

Any ideas? I have tried a strip down and brush through.

[automaton]

Can I air a problem too? My Iwata Tr1 sprays windex, acrylics and future fine, but at all pressures it will not spray alclad for more than a couple of squirts and lacquer thinner will not spray through it either. I used to spray lacquer thinner thru as the final clean. I wondered if it was high pressures evaporating the solvent, but I have tried low pressures. Its a pain cos I do my engines and metalwork in Alclad.

Any ideas? I have tried a strip down and brush through.

 

That's strange-does air still blow through it normally when it won't spray Alclad or lacquer thinner?

 

Regards;

 

Automaton

[DrDave]

yeas it does

[cyarborough]

Very odd problem. I noticed in the TR1 manual a picture with an inline moisture trap. Is this in place on your airbrush? If so, does your compressor have a moisture trap as well? If there are 2 I would try removing one of them. I am just pulling this out of my @$$ but it sounds like you have tried almost everything else.

[DrDave]

Yes I do have too. Theres the little one by the brush and the compressor trap. Do you think the low moisture is evaporating the thinner? Could be, but it doesnt empty the paint cup of thinners. I have stripped it as far as I can and all seems well. Not too mucky.

[automaton]

Yes I do have too. Theres the little one by the brush and the compressor trap. Do you think the low moisture is evaporating the thinner? Could be, but it doesnt empty the paint cup of thinners. I have stripped it as far as I can and all seems well. Not too mucky.

 

That's worth a try, but normally the less moisture in the air supply the better. C02 setups spray well, and have zero moisture. Maybe the lacquer thinner is causing something in the paint path to "swell" and close off the passage? That's why I asked a couple of posts ago if it blew air when the lacquer thinner didn't spray. I thought perhaps the lacquer thinner was leaking backward past the needle packing, down into the air valve and messing with the o-ring. I'm really puzzled on this one-it's one of the more bizarre airbrush problems I've ever heard of. Could there be a dried paint deposit hiding somewhere that's being attacked by the lacquer based stuff and expanding?

 

 

The only other thing I can think of is that for some reason, the lacquer based stuff is causing the airbrush to leak at the back of part 2 in this diagram. If the seal there isn't good, the airbrush will blow air, but wouldn't have a good burnoulli effect to pull paint. I don't see an o-ring there in the diagram (and if not, I don't understand how it seals), but if there is one, I suppose the lacquer thinner could be messing with it and causing a leak. Maybe try sealing the mating surfaces at that area with beeswax?

 

Also, could there be something partially clogging the little vent hole in the cap of the color cup?

 

 

Automaton

Edited April 3, 2011 by automaton

[DrDave]

I like your paint clag swell theory and its seems plausible because the alclad is intermittent and then pulling the trigger right back a good few times clears a passage and alclad sprays a bit more. I have had a good look and all seems clean. Might take out my second trap though. Cheers mate!