Iwata HP C Plus - Problem Spraying Paint

[Warren]

Gentlemen,
I am an airbrush novice with an IWATA HP C PLUS (.30mm needle) airbrush. Yesterday, I tried the airbrush for the first time. I put water in the cup, set the PSI to 20 and it sprayed just fine.

I then began doing airbrush painting drills (circles, dots etc.) with Vallejo Model Color, thinned with Ultimate. All went fine. When finished I removed the needle, cleaned it and then cleaned the cup and nozzle cap. I reassembled the airbrush.

In the evening I tried to do some more airbrush paint drills. I was getting only air, no paint. I removed the paint, and cleaned the air brush removing
the needle and nozzle. I reassemble the airbrush and tested it with water. Again only air, no water.

I did some reading on the internet, and since the nozzle was clean, the conclusion was a badly adjusted needle. Today I tried again with water and had the same problem,

I loosened the needle chucking guide which made the trigger easier to move, and slightly loosened the needle chucking nut. I DID NOT SCREW IN THE PRESET HANDLE. I was able to spray water. HOWEVER, when I screwed in the preset handle I reverted to the same problem, only air, no water.
I loosened the Preset Handle two turns, and I was able to spray water.

I am confused as to why I can spray water only with the Preset Handle slightly loose. I checked that the needle is properly seated.

Any help or suggestions would be appreciated.
Thanks

Warren

[digger303]

Nozzle isn't clean.....there is a small amount of paint in there. Soak it then clean with a whittled down tooth pick very gently.

[Warren]

Digger 303,
As I wrote, I disassembled the nozzle. It was clean. I cleaned it anyway with a nozzle cleaning tool plus nail polish.

Thank you.
Warren

[digger303]

sorry I mentioned the nozzle cleaning, but it is usually the problem despite people saying it was clean.
I don't have that AB, but other brands with the preset handles. If I screw the preset right in I only get air. I have to loosen it a turn or 2 before it will spray anything. Can you spray paint upon loosening the preset.
Hope this helps.

[SteveW]

I loosened the needle chucking guide which made the trigger easier to move, and slightly loosened the needle chucking nut. I DID NOT SCREW IN THE PRESET HANDLE. I was able to spray water. HOWEVER, when I screwed in the preset handle I reverted to the same problem, only air, no water.
I loosened the Preset Handle two turns, and I was able to spray water.

If I am reading this correctly you have wound in the preset which will restrict your trigger movement thus your paint flow. The preset should be wound out. This allows the trigger to be pulled across its full range and thus allow the paint to flow. If you wind it in then it restricts the trigger and thus the paint. Hope that helps.

[Warren]

Steve,
No I did not touch the preset screw. Unless it was loose it is in the same position as I received it when new. However, I think you and Digger are probably correct. Logically it would seem that the preset handle is restricting the needle from retracting when I press the trigger down and back.
So when I loosen the trigger handle two turns the needle can retract and allow paint to flow. This would mean the preset screw is too far in. I will try to retract the preset screw a few turns and see if this does it.
Thank you both for your kind help.

Warren
PS I e-mailed Iwata in Portland, Oregon (USA), and raised the question. What confuses me is that I have never touched the preset screw. Perhaps it was loose to begin with.

[SteveW]

Warren

The preset screw isn't preset by Iwata. You adjust it yourself depending on how much paint you want to flow. If you have good control of your airbrush then you can wind it all the way out and control the pull yourself. Many people only use it when they a need a constant fine control. Personally I have very rarely used it mainly because depending on the paint I am using sometimes I get blockage and need to clear it. Pulling back fully on the trigger and giving it a good blow out clears it and I can carry on from there.

[Warren]

SteveW
Thank you. I loosened the preset screw two turns and screwed in fullly the preset handle. All is now fine. The mystery is that I never touched the preset screw when I received the airbrush. I will now test at what position is best for me.

Warren

[SteveW]

Glad you have it sorted Warren