Hello all,

Not sure if I'm just being paranoid or if a part of my AB is damaged, but has anyone else noticed if their spray stream, coming out of the nozzle, is 100% steady and consistent or does it 'wave' around a bit? Thanks!

100% steady and constant. To me is sounds like you are having a pressure issue or the paint may not be thinned enough for the air pressure being used.

"Steady as she goes" It you have a double action then there will be some change as you pull back on the trigger but no rolling around. Have you done a good cleaning? Try putting the nozzle in lacquer thinner. Inspect the needle for uniformity and bends. Look at the nozzle with a magnifying glass to see if there are any issues like a bent /warped edge or crack. When everything is cleaned, put it back together. Using the magnifying lens and ckeck to see if the needle stays centered in the nozzle as you adjust the spray pattern.

I've checked the needle and nozzle and I can't find any issues with either. The nozzle opening looks perfectly round and I routinely clean the airbrush with windex followed by a water rinse immediately. I disassemble it after each 2-3 hour session and I'm relatively sure there is no paint buildup. I notice slight variations in stream when I shoot water out of it. Still not sure what I can do.

I had a problem like that, then I put in a water trap. I can't say that I've ever actually seen water in the trap. But my pressure is very constant now. Btw, I use a shop compressor, not one of those little hobby compressors.

Good luck,

Gary

The compressor has a tank, water trap, pressure gauge, and is a piston type. So far, the status is that I can't find any fault with the needle or nozzle. When I hold the AB up to a light so that it contrasts, and spray water, the stream is steady for 4-5 seconds, flickers, steady for 4-5 seconds, flickers, and so on.

Could be something wrong with pressure gauge or a blockage in moisture trap. Something is changing the the air pressure.

Check all your connection points.

If you used Teflon tape to seal your connections, check that there is not a piece interfering with the airflow.

Cheers,
Joe

This is starting to sound like an air flow/ pressure issue

Ah, I haven't really looked into that aspect yet. Is it possible that the metal housing which directs the air adjacent to the nozzle has a defect? Problem is, I've inspected it but the hole looks perfectly round. Would a defect here be visible enough of it caused a problem? The compressor is relatively new and there is no Teflon tape on the valves.

your needle bent?
Your compressor may have blown a seal...for inconsistent pressure.
Use silly putty to seal it back up.

I've observed the needle by rotating it under a magnifying glass and can't see any bend myself. I guess next I'll take a look at the compressor and air line.

New observation: when the needle is pulled back and then slowly allowed to re-enter the nozzle, it's not centred every time. Any ideas show to fox this?

Sound like a split tip.

As in broken nozzle? The needle and nozzle seem to be in perfect shape. It's just the alignment that's off.

What type of airbrush and compressor combination do you have? I used to moonlight in a LHS after I retired, and we used to carry a tank compressor line from Model Expo. A couple of the compressors we received had a hairline crack in the pressure valve/water trap fitting which caused the exact problem you describe. I bought one of the returned compressors at a huge discount. A little Teflon tape as mentioned above solved the problem, and it's been working fine for ten years now. As to the mal-aligned needle issue, some airbrushes just naturally come that way, but you might take a look at the needle opening aperture and see if it's screwed in properly (not cross-threaded). It really depends on the airbrush. I've used many Badgers over the years, and I've found one or two that were slightly off, but it didn't have any effect on the volume of air leaving the needle-- again, it likely is a pressure problem. One other thing you can try is the old plumbers trick of brushing a solution of water and soap along the air line and fittings to see if a pressure loss is occurring somewhere. as to the brush, depending on the make, you may need to by a new needle aperture. VR, Russ

KruppCake,
I just thought of this after typing the last message-- check your compressor tank-- most have a drain plug in the bottom. It's there for a reason. If you live in a humid climate like I do, you need to drain the tank every few months because the tank itself will collect water. As water builds, the compressor has to work harder, and it can case fluctuations in pressure. VR, Russ

Than for the advice, Russ. I plan tom soap all the air lines tomorrow and see if there might be a leak somewhere. I've been reading that the needle packing seal has an effect on the needle alignment. Could it be that the nut is not tight enough in my airbrush? I've never fiddled with it myself, so is it something that would need to be re-adjusted?

Addendum: when you put the needle in, it seems flexible to the touch (not the needle bending, but rather it having a very small wiggle in the packing nut). What exactly is supposed to keep it fully aligned to the very centre of the nozzle?

KruppCake,
It would help to know what kind of airbrush you have, the needle packing nut usually compresses a nylon washer, grommet, or packing bushing (early airbrushes had a rubber-like packing that can crack or dry out with time and use, later ones are more likely nylon). The trigger seal (which usually is rubber) might also be a problem. Sometimes they become impacted with paint and can stick, allowing air to get past the trigger. My Peak C-5, Passche Millennium, and Badger 155 all have different types and styles of packing. On a double action AB, the needle should easily slide back and forth in the bushing without binding. A single action AB should return easily to the closed position without binding. From your description of the problem, I still think you are more likely to have a pressure problem elsewhere, what you describe is an oscillation in the air pressure which is common in tankless compressors due to the circulation of the piston. Does your tank compressor run more often than it should? It's worth a look at the needle packing nut though, as air can get by that was well. You should be able to access it from the rear of the AB using a small screwdriver to make an adjustment-- just don't tighten it too much. VR, Russ

Russ,

The airbrush is an Iwata HP-CS eclipse and the compressor is a TC-20T. I see what you're saying. Tomorrow I'll look at the air lines as well as try to clean the packing nut with some windex and a soft paint brush. I'll post of anything changes.

The shape of the needle and nozzle cause them to line up, if it does not always line up, there is a reason for that. I recently had a split nozzle, and it cause all kinds of issues.

Hello all,

UPDATE: as Russ said, it was an air leak problem. Teflon tape on the hose joints took care of the problem.

Also: Needle-nozzle alignment does not matter and misalignment is common. This does not affect the operation of the airbrush.

Thank you all for suggestions and advice!

Needle / nozzle alignment is important for optimum performance. It's why you pay the big bucks for a Micron. Not to say your airbrush won't spray paint, it's just that optimum performance is obtained when needle and nozzle are centered properly.

Paul

True, no argument there. But for model making purposes, most people won't spend $1000 on a precision instrument.

KruppCake,
I'm glad you found the problem. I used to work in a LHS after I retired, and have been using an airbrush since 1965 or so. I've seen lots of airbrush problems. I've found problems usually come down to two things-- air pressure or paint thinning (if you use a quality airbrush-- I have no comment on bargain/cheap airbrushes). But as Paul said, alignment and wear/tear can also be very important when you are applying paint to the model. It's amazing what a little teflon tape can do to improve an airbrush! VR, Russ