You can’t get around it no matter what kind of paint you use water based or solvent based sooner or later the air valve is going to start sticking. Press down on the trigger and it does not spring back up you know it might be time to think about replacing the parts that make up the air valve.Written by Don Johnson airbrush artist
This problem can be pretty annoying but it really does not render the airbrush unusable as I’ve used mine for weeks with this problem. You simply hook the bottom of the trigger with finger and pull the trigger back up. In other words don’t panic if your HP-CS/Eclipse if, when you start encountering this problem.
These are the parts you will need to rebuild the air valve in your Iwata HP-CS Eclipse:
Iwata part number Part Name
1-580-1 Packing Valve Piston O-Ring
1-608-1 Air Valve Guide Body
1-609-1 Valve w/ O-Ring
1-035-1 Valve Spring
1-611-1 Air Valve Guide
While we are at it we’ll replace the needle packing nut:
1-725-1 Needle Packing Screw w/ Teflon Bearing
The only tool you’ll need is to get Air Valve Guide out, it screws into the airbrush. For this I use a pair of snap ring pliers filing the points down just a bit. You can buy a cheap pair of snap ring pliers at any hard ware store for a couple bucks.
In the picture above you can see the Air Valve Guide, the two holes is where you will fit the snap ring pliers into to turn it out. Remember “righty, tighty,…lefty,loosey” when trying to unscrew the Air Valve Guide. Notice in the picture how the valve stem sticks thru the hole in the center of the air valve guide, you’ll need to ensure it does when you put it all back together.
Here you can see the air valve guide has been unscrewed and is out of the airbrush. Pictured is the old air valve guide as well as the new one we’ll replace it with.
Above you can see the air valve guide, spring and valve have been removed from the airbrush. Now we’ll remove the air valve guide body, you’ll see it just slides out. We’ll be replacing all the old parts with new parts.
Here all the parts have been removed.
One more part to remove and that’s the packing valve o ring which is located inside the airbrush, the air valve guide body actually sit on top of it. You’ll need a small pick to get that small o ring out of there. In the picture you can see the old o ring which fell apart and the new one I’ll be replacing it with.
While we have the airbrush apart this much we’ll go ahead and install a new needle packing screw. The needle packing screw is located inside the airbrush between the color cup and trigger. You’ll need a long skinny straight screw driver to exact the packing screw, the packing screw just turns out like a normal threaded screw. When installing the new one be sure to just turn it a turn or two, DO NOT over tighten this or your needle will not slide thru it. In fact do not tighten it much at all…
Laid out in this picture are the parts in order of how they go back into the airbrush.
With the valve body be sure the tiny hole points front to back in the airbrush when you insert it. With the packing screw installed, the valve body next comes the valve (the short shaft goes in first as pictured above). next would come the spring which slides over the valve and finally install the valve guide nut using the snap right pliers.
There you have it. With my HP-CS using solvent based paints for 3 to 8 hours a day, seven days a week I have to go thru this process about every other month. If you just airbrush for a hobby once in awhile you might never have to go thru this process.