Iwata Hp-c Advice

[gunnie3035]

I have a Iwata hp-c gun that has been giving me problems. I've used it pretty hard over the last couple of years and I figure its about time for something to wear out. The only thing I've replaced is the needle because I accidently bent the old one while cleaning it. Now when I depress the trigger the airflow is slow to stop and sometimes won't stop at all. After messing around with it I discovered the air plunger or whatever its called [maybe valve stem?] is slow to react after letting off the trigger. I cleaned it several times, but it didn't help much. I figured I would buy a replacement part and be back in business. Thought I would replace the nozzle while I was at it. That was until I discovered the two parts alone would cost me over $80. Any ideas how to fix this problem or should I just junk it and buy a new brush for $100??

[mark poulson]

Have you tried soaking all the parts, including the assembly that's at the bottom of the brush, where the air hose connects, in acetone?

Every once in a while, I break down my brushes completely, and do that. Then I reassemble them and do a backwash with acetone, and then with air brush cleaner, to get the system purged of the acetone and ready to paint.

All my cleaning and backflushing between coats eventually forces dirty water back into the brush, and it needs to be thoroughly cleaned every once in a while.

[benton B]

Try a couple of drops of iwata oil and see if that will fix the problem. It has worked for me several times.

[RayburnGuy]

Hey Gunnie,

If your shooting water based paint have you tried the Createx brush restorer? I thought I had been cleaning my brush pretty well until I let it soak in the airbrush restorer. I couldn't believe all the gunk that came out of it.

[gunnie3035]

The brush is paint free. I thought about putting some machine oil on the little brass piston, but I was afraid it would mist some of the oil on baits. Seems strange to me the parts for these brushes are so expensive its cheaper to replace than repair. I wanted to make sure I was over looking an easy fix before I purchased a new brush.

[fatfingers]

I have a Iwata hp-c gun that has been giving me problems. I've used it pretty hard over the last couple of years and I figure its about time for something to wear out. The only thing I've replaced is the needle because I accidently bent the old one while cleaning it. Now when I depress the trigger the airflow is slow to stop and sometimes won't stop at all. After messing around with it I discovered the air plunger or whatever its called [maybe valve stem?] is slow to react after letting off the trigger. I cleaned it several times, but it didn't help much. I figured I would buy a replacement part and be back in business. Thought I would replace the nozzle while I was at it. That was until I discovered the two parts alone would cost me over $80. Any ideas how to fix this problem or should I just junk it and buy a new brush for $100??

Look in the hole that the plunger goes in inside the airbrush...but look in the hole where the air hose attaches (after you've removed the plunger).

Inside that hole is a rubber O-ring. Replace that O-ring and your problems are over. It will cost you about $5 plus shipping. I always order a few extras and keep them on hand.

To remove the O-ring, you'll need to use an old needle to sort of pick it out of there. To replace it, you need to wet it and put it in the hole and then guide it into the slot with the blunt end of the needle.

Also note that there is a special oil that you can buy for about $8. You should order that oil also. I use it to oil the plunger, which keeps it from sticking to the gasket, and I oil the needle with about a half drop of oil.

The oil is specially made for the airbrush. I'm sure there is some other oil out there that is the same thing for a lot less, but I bought mine about two years ago and I haven't used it up yet so the cost is negligible when you consider how long it will last you.

No, the oil will not harm your paint work or cause any problems what so ever. Just blow some air through the airbrush after oiling the needle and/or the plunger and you will be good to go.

Before you order anything, try pulling that O-ring out and cleaning it thoroughly. Might do the trick till you get a replacement.

Edited March 2, 2010 by fatfingers

[68KingFisher]

When any of my airbrushes begins to hang up, and continue to blow air after i've let off the trigger, I do the following. I remove the needle and trigger assembly, and the airhose so that I can get to both sides of the airvalve.....Holding the airbrush upside down I put a drop or two of airbrush lube into the valve where the airhose attaches....While still holding the brush upside down i'll take the needle and using the butt end of it, i'll begin working the plunger from inside the airbrush body....moving it just like the trigger plunger would do. As you do this the oil will work its way thru the airvalve and you'll feel it begin to free up.....I repeat this process several times then I flush some lacquer thinner thru it to clean out the lube so it doesn't contaminate my next project.

I've done this for many years on Paasche, Badger, and Iwata airbrushes, and its always fixed the problem. If you don't have airbrush lube on hand, I have subsituted "Glycerin" which you can get from the local drug store....In fact I think a few so called "airbrush lubes" are nothing more then repackaged glycerin. I have also used 3-n-1 type oils, as well as sewing machine oil and even hydrolic transmission fluid when I didn't have anything else on hand.....just make sure you flush the valve with thinner or alcohol or something equivelent when your done using the oil so it doesn't wind up contaminating your next paint job.

[gunnie3035]

Those were the answers I was looking for, thanks fellers. I oiled the plunger and it seems to work fine now, but still doesn't seem to be as smooth as it should be. Feels like metal on metal when the trigger is depresed [worn o-ring?]. I used machine oil and I will order the O rings as suggested.

[68KingFisher]

Well, actually those parts are "metal to metal" so what you feel may be correct....I personally like to have a film of lubrication between those trigger parts because it is just raw metal to metal contact, so I use airbrush lube or glycerin and apply some to those parts succeptable to the most wear....I just want a good film of lubricant on those parts....I think it makes the trigger action a bit smoother also and has to help cut down on wear and tear of those metal parts.

Replacing the O-ring may or may not change anything for you. I know alot of folks that have needed to change them out, but after 30+ years of airbrushing i've never changed one on any of my airbrushes, and i've never understood why others seem to need to replace them so often and I never do....lol. Go figure.