the paint skips

[Rios87]

hello everyone,
today as i was airbrushing i ran in to problem. when i began brushing my paint flow and everything was going smoothly, but about 5 minutes later the paint flow started skipping, it didn't have a continuous flow anymore. how would i solve this problem. please help. thank you in advance.
rios

[landsbro]

Originally Posted by Rios87

hello everyone,
today as i was airbrushing i ran in to problem. when i began brushing my paint flow and everything was going smoothly, but about 5 minutes later the paint flow started skipping, it didn't have a continuous flow anymore. how would i solve this problem. please help. thank you in advance.
rios

Hi rios
hmm,,if you tell us what kind of paint you are using it would
help us too,,and what type of ab,gravity feed or bottom feed.
anyhow sounds that you have some dirt/dried paint in the nozzle
think you need to clean it,,if you got a gravity feed(cup above)
add some water or cleaning liquid to the cup and "backflush" cover the opening of the nozzle with your finger tip and press the trigger gently
now you will see bubbles in the cup this forces the dirt in to the cup
empty the cup and add some more liquid and do it again
repeat this untill the liquid is free from dirt.

another thing is that the needle can be bent
/kimo

[ArtWorld]

Kimmo gave you some great info.

It could be a few other things as well. Moisture in the line, oil in the line, compresor might not be giving you a costant flow of air, inconsistant paint, nossle or cone on airbrush is completely inside the front of the airbrush, nozzle not sealing well inside the airbrush, bad o-ring. I am not sure but you may want to check your airbrush manual or pull one up on it, an dlook in the trouble shooting area.

Also could you let us know what kind of airbrush and compressor you have as well as paint and wether or not you have a water/oil filter trap? Then we could help you out on this better.

Brad

[Bahamut]

I use bottom feed airbrushes a lot. If the hole on the top of the bottle is plugged with paint it will make the flow skip. Check that if you're using a siphon feed AB.

[Rios87]

i have a bottom feed dual action airbrush. not the greates brand (central pnumatic) same brand compressor as well. its oil less.

[KDSilverBrush]

sounds like dry tip on yer needle is all.

[fontgeek]

Rios, what kind of paint are you using?
How thick is the paint?
What size needle and nozzle does your brush have?
How much air pressure are you using?
What is the environment or painting conditions like? (Hot, cold, humid, etc.)
Do you have a regulator, water trap, and filter in your setup?
Does your compressor run smoothly when you have these problems, or does it make any noise, etc.?

Too much air pressure can make your brush skip, just as too little can.
Ideally, you probably want your paint at about the thickness of skim milk, you need to make sure your brush is nice and clean, and that the vent hole on your airbrush's paint reservoir/bottle is open. If that is clogged, then it blocks air from coming into the bottle when you spray, that air is needed to displace the paint as it is sprayed out. If your brush can't get air pulled into the bottle, then it creates a vacuum that will keep your brush from being able to spray. If you have paint caked on or around that hole, then it may block the vent intermittentlyÒ.

If your paint is too thick, then it makes it tough for your brush to spray it out.
Make sure your paint is properly thinned, mixed, and strained BEFORE you put it into your airbrush. If your paint wasn't mixed well, then you may have sprayed the thin liquid off first, then, when your brush got to the thicker stuff, it choked.
If you are working in really hot conditions, your paint may have started drying out in the paint reservoir, making it too thick for your brush to spray.

Dirt, oil, water, or other debris in your air source or airline/hose can also cause your brush to sputter or stop working completely, it can also do permenant damage to your brush and or your painting surface.
There's no such thing as having your air to clean or too dry.

[Bill]

A word of caution about "backflushing". I recently attended a seminar put on by ASET, the importer for IWATA airbrushes and one of the speakers there said do not backflush an airbrush. Doing this can force the paint back along the needle to the seal in front of the trigger and ruin the seal. As others have said, clean the entire airbrush and then when you put it back together make certain the nozzle is tight. I had a sputtering problem and it was caused by me only tightening the nozzle with my fingers. Use the wrench and make it snug.

[fontgeek]

The only way paint would be forced back through the paint passage, and past the needle packing/bearing/seal, is if it can't escape or release pressure through the paint reservoir cup or bottle. If your brush is packed up that bad, then some paint getting past your packing is the least of your worries. I'm not doubting they told you this, I am doubting the person(s) understanding of what you are saying, or of how an airbrush works.
The paint and air are going to take the easiest route of escape, in normal operation of an airbrush, that is through the needle and nozzle caps for the air, then, if the opening in the nozzle cap is blocked, it, the air, passes back through the nozzle, through the paint passage, and into the paint reservoir, where it makes your paint or solvent bubble. All backflushing is is you, the operator, doing this on purpose.
For the paint to be forced past the needle packing/seal, it would mean that all other exit points for the air have been blocked, that includes the nozzle and needle cap, the paint reservoir cap or lid, the lid vent hole, the male and female openings for the siphon or side feed variety of brushes, and the fittings on those bottles or cups.
Personally, in the 30 or 40 years of airbrushing I have had, I have never seen a brush so plugged that it would or could push the paint back past the packing/seal. If the paint is so dried and packed that it can't go out via the reservoir, it is way to dry or thick to go past the packing.

As far as your packing being exposed to the paint itself, it gets that everytime you airbrush, that packing just acts as a squeegee, and wipes the needle clean when you pull the trigger back. No more, no less.