Let's go over air compressors...

   / Let's go over air compressors... #11  
I had a single stage 60 gal and upgraded to an 80 gal 2 stage. It is made by a local outfit here called C'Aire and is industrial quality. For spraying, I use a turbine driven HVLP but the air sanders can really work the compressor. It has enough capacity to keep up when I use the 6" ROS full on as it will catch up and stop eventually, but it does run a long time. Since heat is the enemy, I point a shop fan at it when I run it hard to help cool it more. So the question is what do you really need? Someone mentioned needing a portable one and that is for sure, but those can be fairly small, and you probably have it covered with your 20gal. If you have the space and power for a large fixed unit, it can allow you to run sprayers and high draw air tools like sanders and blasters that you could not do very well otherwise.

Ingersoll used to be a good brand but it sounds like they have become trash in the past few years. I have seen several people complaining about defects in new IR compressors and very poor response from the mfger so I would avoid them. Most of the cheaper brands you will find in Fleet Farm, etc are going to be lower quality which may or may not be enough for what you need. If you rarely run them hard, that may be fine. If you run them hard all the time, then they will prob not last. But if you are going to buy a cheaper/less durable one, don't spend extra for a name like IR that has lost their way. Quincy is a known good brand but I have also heard they have a cheaper line of imports now. Atlas Copco too is higher end. All depends on your needs and wallet.
I will second that from personal experience about new IRs being foreign made trash and IR "customer service" being near non-existent
   / Let's go over air compressors... #12  
I have a Quincy 5 hp two stage 60 gallon and has performed well for 10 years
   / Let's go over air compressors... #13  
Look up the CFM requirements for the tools that you want to run. If you're running them constantly like a sander then you want a compressor that exceeds that. If they are intermittent like an air nailer then the compressor can have a lower CFM and fill the tank while the tool is not using air.

Also if you're going to have people running multiple tools at once you'll want more CFM.

A way to get the water out of the air is a good idea. There are home made air coolers (i.e. lengths of copper pipe) or you can adapt or buy a cooler. When the air cools the water vapor condenses and then a water separator can catch it. If it's vapor it will sail on through. Just a little water can make sand blasting a chore and can ruin a paint job. When your tool uses more air than the compressor and you have to keep waiting for the compressor to catch up, the compressor and tank will get hot and there will be more water in the air.
   / Let's go over air compressors... #14  
After having a 7.5 hp ingersoll in the 10-15cfm 150psirange, I couldn't imagine going to a lesser unit. It was around $400 on market place

Buddy also has a curtis 5hp that's bullet proof

I wouldn't go less than 10 cfm. Its nice to be able to run any tool virtually non stop and never worry about air
   / Let's go over air compressors... #15  
I have a Quincy 5 hp two stage 60 gallon and has performed well for 10 years
"Buy a Quincy for life".

We may have the same compressor. Mine is a QTV-4E 60 vertical.
   / Let's go over air compressors... #16  
I have four electric compressors and a gas powered model. When we need big air in the shop, I turn on my Lei Roi 5HP two stage, I bought it new in the early 80's and it's been a joy to own!

I've always believed in buying quality tools, and that's exactly what I did way back then and it's still paying off!

My other compressors are also older, back when tools were made decent, and that's what I recommend you do now, buy QUALITY and something big enough for future needs!

Buy once and cry once!!

   / Let's go over air compressors... #17  
I have a Quincy 5 hp two stage 60 gallon and has performed well for 10 years

"Buy a Quincy for life".

We may have the same compressor. Mine is a QTV-4E 60 vertical.
I also have a 5hp Quincy two stage on a 60 gallon tank and it has been trouble free since 1985 other than replacing the start capacitor switch a few years ago. I change the oil every couple of years and haven't even had to replace the belt yet.
   / Let's go over air compressors... #18  
Your big item is volume of air flow not pressure. So, as advised, get a compressor that meets or exceeds the volume demand. The tank size is rather immaterial as when using the compressor you are just running on the compressor volume when used for extended times.
   / Let's go over air compressors... #19  
Quincy’s are high quality, I don’t own one but they are made near me in, you guessed it, Quincy Illinois. They sell them at the local farm store and if I need another I’ll probably get one.
   / Let's go over air compressors... #20  
Quincy, Saylor Beal or the older IR vertical twin 2 stage compressors are good. The newer radial multi cylinder (Chinese made) made ones, not so good. Keep in mind that under heavy demand the petal valves in the head get real hot and eventually carbon up but can be cleaned easily.

Rotary screw compressors don't have any of those shortcomings. A rotary screw is like the blower on a race car engine.