shepo1

HI
Upgrading my compressor.
Current unit
Craftsman 30Gal 5HP 150 PSI..
Cant keep up with my air tools..

So.. single vs dual stage compressors..
Advantage's and disadvantages??

from what I can figure out.. The CFM rating is what the unit should be able to produce constantly at the given PSI??

Example 15 CFM at 100 PSI.. This unit should be able to give me that at 100% use ? If so then that is also the rating of the pump.? So if Im using 15CFM at 100 PSI.. the pressure in the tank drops till the pump kicks on.. then the pump will produce 15 CFM to keep powering my tool, until i stop and then the pump will continue to run putting compressed air bank into the tank ??

If so then single vs double doesnt really matter as long as the CFM/PSI rating is above what you need ?

If so.. the only advantage to a dual stage unit is that it can achieve higher PSI 175 ish vs 135 is on a single stage. Since most tools dont require over 100 PSI.. what would I need a dual stage for

I would think a multi cylinder single stage might be better ? More cylinders means more CFM and recovery time vs a single cylinder dual stage ?

Thanks.. just trying to figure it out.

shepo1

Found this document that has good info about how to select.. Probably answers my questions.. posting for others with same questions..

http://www.cagi.org/pdfs/cagiaircompressorhp.pdf

don71

That's a good read and very thorough.

Your current compressor is good for the small stuff. I'm guessing you've been doing a lot of DA sanding? Yea, its tuff to keep up with that, and blasting abrasives.

My set up is very similar. I have painted and refinished many things including autos. It can be done, patiently.

I think with what you are looking for will require 220v. Keep that in mind.

m371961

Watch the duty cycle if it is given. A 100% duty cycle means it is capable of continuous running.

BackInTheGame

Dual stage, 240VAC will recover faster and cost less to run over the lifetime of the compressor. Single stage has to work harder (more amperage) to produce the same amount of CFM. Last winter I replaced my 5HP/30Gal unit. I figured I'm spending the $$ anyway - do it right and go big. Picked up an Ingersol/Rand 5HP/80Gal Two stage 240VAC for $1050 on sale. Best G I ever spent for the garage. I can literally run my blast cabinet for hours on end without stopping or pausing for the compressor to catch up - it turns on and runs up to pressure, and shuts off while I'm still blasting, then runs some more. Cycling like that. Same with a D/A sander, airfile, etc. I say if you are going to be doing body work, don't skimp, otherwise you'll wish you had pony'd up the $$ to begin with.

YMMV.

Ozzie

You have a good information from the web and the forum. Remember that you may acquire more air operated tools as time goes on. Single stage will operate most tools, but the higher pressures are needed for things as lifts and spark plug testers (does anyone still use these?). Larger compressors require larger electrical feeds. Three phase power is best but most of us must survive with single phase. Just be sure that the circuit has enough capacity for the compressor. In all cases, a bit oversized is better than a bit undersized for compressors as well as electrical circuits.

chadman

I just went through this myself and ended up with this Puma for $650 shipped to my door:

http://www.aircompressorsdirect.com/...ssor/p591.html

The only real advantage to a two stage is that it pumps to a higher pressure. This is basically like having a bigger tank because you are compressing more air into the same space. Once you have depleted this reserve the CFM rating is all that matters and you will find that the two stage compressors have about the same CFM rating as comparable HP single stage units.

Also, that 5hp rating on those 30 gal. Craftsman compressors is misleading. That is the peak HP and not the running HP. They are actually just under 2 HP running. I have the same unit myself. I am plumbing my shop in 3/4" black pipe and will be connecting both the new 60 gallon Puma and the 30 gallon Craftsman to the air line system. I plan to leave the switch turned off on the Craftsman compressor except for times of severely elevated air demand such as sandblasting and such. The remainder of the time I will just use the Puma to supply air to both tanks giving me 90 gallons of tank capacity.

shepo1

thanks guys.. i pretty much determined that a 60 gal would be barely enough. 5HP 2 stage 80 would pretty much do what ever i need.. Now to figure out how to get it into my garage..LOL things weight like 500 lbs... hmmmm guess i need to buy a fork lift !!! lol