airbrush: difference between bottle- and gravity-fed?

I am responding to more messages that I thought I would!

I have used both gravity and siphon feed airbrushes.  I primarily use gravity fed brushes or side feed brushes at this time for a couple of reasons.

First of all, you have greater control of your paint with a gravity fed rush than you do a siphon fed brush.  The reason primarily is that your paint is directly in line with the airflow, and fed by gravity.  You don't need to have any kind of suction in order to feed it into the airflow, you only need to pull the needle back.  This allows you to spray at much smaller PSIs than you would with a siphon fed brush.  I can and do spray regularly between 5-15 psi when working on very small models or figures, as well is what I'm trying to get very specific effects.

Too, this is great for control of overspray.  I've kept an airbrush at times sitting on my workbench what I'm painting, and can use it along with brushes to get certain kinds of effects -- for example what I'm working on a face or flesh tones, I can keep one of my brushes loaded in sitting or I can grab it.  I do washes/highlighting, then soften it back to the original tone.

I can also use air to dry things a lot quicker.  But, I'm kind of a goofball.  I like using my airbrushes as much as I can.  heck, I've spent the money out all the equipment, why not use it?  :)

For cleaning these brushes, here's some things to keep in mind:

-- I agree with not cleaning them thoroughly between each use, but running cleaner through them.  Various airbrush artists also suggest keeping a small bucket of water near your work area, where you can get the brush in for assistance with quick cleaning.  There are couple of techniques that work really well for cleaning  your brush as well, but they're hard to explain without showing.  One of them is as you are spraying the cleaning solvent through the brush, you whole the needle back as far as it will go, and pressure finger or cloth or what ever over the opening, and you will get air that feeds back into the well of the brush.  This "blowback" method is superb for cleaning out your brush really rapidly. 

-- I keep squeeze bottles that contain water, alcohol, and Windex.  What ever paint is remaining, I diluted with water, and tip it out.  Then I run the Windex through it until there is no more color.  You can wash it with some water or alcohol as well and it's ready to go.

-- you can get really quick changes with a siphon fed brush, but the real issue is control.  I think you get a lot more control with a gravity fed brush than you do a a siphon fed one, especially at low pressures.

Re: pistol grip -- I don't have one, I have a moisture trap in line with my hose.  I've never had any problems.  I think it depends a lot on your source of air -- if your compressor heats the air a lot, you can have a lot of condensation, and this can be problematic.  The pistol grip looks good, but if you're like me and use quick releases, you'll need one for each brush.

I really should do a web page on this stuff -- there is so little information on this stuff out there, and if you're like me, you can hold your hair out trying to figure out what to do, what to get, how to use it, etc.  Airbrushing is a phenomenal skill set for modeling, so I would recommend anyone who's serious about it learn how to do airbrush.

First off, air brushes aren't convenient. They can be frustrating, difficult, humbling and impressive, but not convenient! As previously stated you must clean a bottle the same as a cup. I have two ABs, Badger 100LG and 150 siphon, which may be the exception to my statement. Since they share parts I guess one could say that's convenient! Also I have a couple of color cups for 150, which means I can simply pull one cup off, do a quick clean up of the brush and install the second cup and continue. Of course that also means I have two cups to clean up after, but I use acrylics and simple dump them into a container of Windex until I'm ready to clean up. Then it's a simple rinse and a quick ream with a pipe cleaner and I'm done.

The benefit of gravity fed is the simple fact that you can lower the air pressure as the paint is self feeding, compared to siphon fed, where the air pressure must be high enough to pull the paint up the siphon tube. Lower pressure can mean thinner lines. I say "can mean", since other variables also come into play such as: proper thinning of paint, distance from surface to tip, and steadiness of your hand.

I used to think I didn't require a moisture trap, but airbrushing without a moisture trap will ultimately teach you how to strip paint and start over, as eventually moisture WILL be squeezed out of the air and onto your lovely new paint job! It's a fact of life! I would imagine ewc2003 has been quite lucky in that his tankless mini-compressor probably hasn't run long enough, or doesn't produce enough compression to cause a problem. Yet!!

I've seen the pistol grip filters, but have never used them. It would require a slightly different technique to use one, and I wonder if the length of the handle would get in the way?

The closer you can get a moisture trap to your air brush the better . I have no experience with an pistol grip filter but it sounds like a good idea .

 

I've only had siphon feed airbrushes but here's my take.  There isn't any "convenient" brush really as you'll need to run some sort of cleaner jar in between colors at the very least.  The main difference in having a gravity-fed airbrust is that it allows you to spray at lower pressures, for finer lines and better control, since you're not using air to "suck" the paint into the airbrush per se.

I have a Badger Crescendo 175 and personally I love it for general purpose stuff.  I only have one "jar" and it's always loaded with acrylic cleaner as that's all I spray (in an apartment so gotta get the least "fumy" paints for now).  I use the color cup that feeds to the bottom and then is sucked up.  When I'm done with one color, I take a pipette full of windex, blow it through, clean the tip and needle, then run enough cleaner through till it's colorless, pop the color cup back on, load up and repeat.  At the end of the day/night, I take it apart, draw the needle out and clean it all up before putting it up until next time.

About the moisture trap... I don't use one as I use a tankless mini compressor so I don't have too much water in the 6' line.  A regulator is an absolute MUST however.