Hello,
If you need a nice super-silent compressor for your airbrush but you don't want to spend a ton of money, you can build one (not much of a news) with a fridge compressor.
I bought my first air compressor 12 years ago. I always used normal large compressors and I wanted one specifically for my airbrush. I bought the basic badger. When I received it, I plugged it in, tried it, realized that it definitely sucked, put it back in the box and returned it. I looked for better compressors but they were very expensive. So, I opted for a small campel Hausfield you can buy at WalMart: http://www.walmart.com/catalog/product.do?product_id=4021.
It works like a champ, it is noise but not too much. The only flaw is that,after 12-24 hours of use, the connecting rod brakes. I had three thus far, they all broke after a few hours of operation. It sarcastic, the sticker on the compressor says "built to last," yes, maybe, but they forgot to put for how long.
So, last week I broke the third one. I decided to go for a very nice one, my choice would have been the silent air. The ones that I considered were the Sil-Air 50-24 ($959) or the Sil-Air 50-6 ($879):
http://www.madisonartshop.com/silair-5024.html
http://www.madisonartshop.com/silair-506.html
Before sinking that much money into a nice compressor, I decided to give DIY a shot. I decided to modify the broken Campbell Hausfieldreplacing the motor with the compressor of a fridge. I found an old fridge for $20, bought some 1/4" tubing and some fittings at Home Depot. For $40 and 4 hours of work, I built a super silent (to check if it is running I need to put my hand on top of it top to feel the vibrations).
It is a cheap perfect solution. If you don't have a small broken compressor, you can use any kind of tank,bbq propane tank, fire estinguishers etc. The best solution for me is to buy a portable air tank at Autozone, eBay or Amazon. Like these:
http://www.amazon.com/gp/product/B000FW7W54
http://tinyurl.com/q5nhe2
http://tinyurl.com/r58lec
Plus one inline pressure regulator like this http://tinyurl.com/qul73w
a pressure gauge, like this: http://tinyurl.com/obs67b
And an oil filter and pressure switch
You can find these parts for a few bucks at Walmart, home depot, autozone, ebay etc.
You'd spend, total, around $70-100.
The best way to go ids: buy the same compressor I modified, use it until it brakes and then modify it (maybe I had very bad luck and got three lemons in a row, yours could never break).
This is the one I made:
http://tinyurl.com/Compressor-1
http://tinyurl.com/Compressor-2
I hope this will help you saving some money. I will eventually buy the silentair, but this one will do until that day. I'll keep you posted if I have problems with it.
Ciao,
Paolo