Air Pressure

This is normal behavior, just set the correct pressure while depressing the trigger to insure consistent pressure.

tbuslewicz

I just started modeling last year and have been slowly ramping up my techniques.  I just went from a Badger 350 to a 150 and put a regulator on my Testors blue air compressor.  I noticed that when I depress the button on the airbrush the pressure goes down.  From everything I am reading about air brushing I would think I would want to maintain constant pressure.  Is this normal?

No, it is not normal. A good compressor should maintain constant pressure. But the Testors Bluemax is NOT a good compressor. Unless you find the pressure from Bluemax way too high for your painting, the regulator is NOT needed. In most cases, the Bluemax will have barely enough pressure for painting. If so, remove the regulator because it lowers the pressure unnecessarily.

Or is it just that the compressor is too small (or cheap) to maintain a constant pressure. 

This is typical of many of the cheap airbrush compressors. However, most of the regulator pressure reading are inaccurate (gauge at the wrong location). The Testors Bluemax can provide sufficient pressure to run a Badger 150 if you thin the paint sufficiently. Experiment and find the solution that you can live with.

I was thinking of maybe switching over to a refillable airtank - would this provide constant pressure?

You set your working pressure with the airbrush flowing air through it. Some drop is noticed, must has to do with the quality of the gauge.

Regardless of what you use to pump or act as an air reservoir you need to control the flow. Think of a faucet, you want the water to run at a specific rate, you have to have a valve (the faucet) to control the flow. A large portable air tank will push more air out the valve when it is full and less as the pressure between the tank and outside atmosphere equalize.

A good compressor or a CO2 setup is the two best options. I've done the portable tank route once. I was always out of air when the time was available to paint. Finding a gas station that actually has air is getting more and more difficult. When you do, you find you have to pay or you have one that pumps contaminated air...water, dirt etc.

Thanks all for the feedback.  I guess I just got what I paid for here - the compressor and gauge were definitely bought on the cheap.  Guess I will have to upgrade again.  Where would one get a CO2 tank setup?  I am king of leaning that way.

Visit either a beverage supply company...those that service restaurants and bars or a welding supply company that sell bottled gases. Check your local business listings.

You'll need a bottle and a suitable regulator. The bottle you lease, the regulator you purchase. Be sure to tell them what you are using it for and take along your airbrush hose so they can get you set up with the correct fittings.

It is actually normal. What it means when it calls for a constant pressure is that even though it will drop slightly when you depress the trigger, the resulting pressure will be constant which you have said that it is. If your compressor is working for you then keep it. More expensive is not a guarantee of improvement in results. It is easy for other posters to spend YOUR money! If it is working then don't change it until you are ready to grow more in your modeling commitment.

As rippel66 said, yes it is normal depending on how much it drops.

Both my Badger Million Air and my Jun Air silent compressors show a slight drop in pressure from a static state (airbrush at rest) and when the airbrush trigger is pressed.

The problem is likely not the compressor, but the flow rate of the regulator.  On the other hand, this is quite normal with most regulators.  As someone else said, just adjust so that pressure while flowing is what you want for pressure.  I have had three regulators, and each did that.

I went to the local welding supply store to purchase my CO2 tank and regulator (a decent one), and at the time (about 5 years ago) it cost me around $220 for the whole setup.  I only model a few hours a week so I'm not a heavy user, but I only have to go to the welding shop about once every year and a half to swap out the tank for a full one at a cost of about $15.  I'm completely sold on the CO2 approach to powering the airbrush for  the following reasons:  1) it's silent (which is appreciated by other family members);  2) moisture problems are non-existent with CO2 as the propellant (so no moisture traps are needed); and 3) you can dial in the pressure with pinpoint accuracy.  Considering that modeling is one of my main hobbies, I just didn't think it was that big an expense to step up to a CO2 setup---- and I was right!  In all the time I've used the CO2 tank, it has functioned flawlessly, and I can honestly say that I have never had to spend a single minute of my modeling time on screwing around with my air supply.  For less than the price of one golf club, I've got about a third of the equipment side of my modeling hobby covered forever. 

Tom