Actually the one I have works pretty good. I was used to one that produced 20.2 cfm so even though I still have a large compressor it felt small

 

I only paid $399 for my kobalt at Lowes. Its a 60 gal 230v I cant quote the delivery right off hand. But most tools used regulary ask for 90psi or less. My compressor keeps up very well. I could see if you was running an auto shop and had muti bays running day in/day out needing a high end compressor.

 

It largely depends on the air tools you use as well. I had a Porter-Cable 60 gallon 220V 3HP compressor that the manufacture claimed delivered 9.7CFM @ 90psi, but it could not keep up with my media blasters, DA Sander, and HVLP gun (individually not together). You can get by with this size compressor with these tools if your patient and you don't mind waiting for the compressor to catch up. The bottom line you need to size the compressor to your needs or how you plan to use it and your budget. If you only plan to use it occasionally for filling tires, air-nailers, impact guns, or on small projects then you don't need a monster compressor. It's like buying an F-350 4x4 to drive to work and back with your largest load you ever carry are 6 bags of groceries.

 

Are you saying youneeded more than 9.7cfm or that the compressor would'nt deliver 9.7cfm?
My kolbalt claims it'll push those things intermitted. So I'm pretty sure I might have to wait on some things but then again yesterday I blew out the cab of my truck and then the leaves out of my shop and I was,nt ever waiting on air.
Now I believe there is ways to in prove on a systems delivery. At work almost everthing is run on air. All our bin doors are air cyclyders. Our truck lift is on air. One time the compressor we upgraded to was'nt keeping up.In the end we got a 300 gal tank and everything comes out of that tank. We have a 200 gal tank on the side I thinkits a pop off for the 300. I'm not sure about that. I just know its teed in with the 300.

 

Exiled, a lot of air compressor manufactures tend to mislead consumers about the CFM output of their compressors. Some tend to print CFM ratings that are based on piston cylinder displacement values x rpm, which is not a real world measure of what the compressor actually delivers. My old compressor manufacturer claimed 9.7CFM @90psi and I don't know how they calculated these numbers, but I'm sure it was in that ballpark (but probable lower). The Porter-Cable one I had and Kobalt one you have that are sold in general retail stores to the general public, probably have over-inflated CFM ratings (pun intended) to help sell compressors.

To answer your question, the 9.7CFM @ 90psi rating of my old compressor was not able to keep up with my indoor media blast cabinet or the pressure blaster that I use outside. The blasters would work OK for a time and then the pressure would fall so low that it took me forever to finish blasting large projects. It took me 5 full weekends (6-7hrs/day or ~60-70hrs) to sandblast my 77 F150 truck frame! A commercial blaster would probably have the job done in under an hour. My new Eaton compressor is an 80gallon, 5HP, twin cylinder compressor that puts out 20CFM @ 90psi and I was able to completely sandblast the 77 truck cab in about 18hrs (3 six hour sessions) and there is a lot more surface area in truck cab than on the truck frame. The compressor still ran almost continuously, but the compressor pump/motor was able to keep blaster working great from start to finish. I read somewhere that if you double your CFM rating of your compressor you will triple your media blasting efficiency.

 

To be real honest w/ you I'm not inteirely sure what cfm actual means in a real world schem of things. I do know however it is the true power rating of a compressor much like torque is to an engine horse power just tells you how fast you can use the torque.{or something to that effect}
Do you think your eaton's rated 20cfm is inflated? My kobalt brags that it will deliver 11.5 cfm @90 psi and 13.4 @ 40 psi. This is just a 3.7hp motor. I wonder how much the extra 20 gals of air helped ya. I'm kinda wondering what would have been the results if you where pumping into a 50gal tank or larger. I did some checking at work on our compressor. It first was hooked up to the 200 gal tank and could'nt keep. The 300 gal now can. Same compressor.
The cheapest 80gal compressor I could find was over $800. I'm just betting that for under $400 I'll beable to get a tank and keep up if I ever take on a job that murders what I have now.
But you blasting you truck yourself probally paid for the compressor.

 

CFM = cubic feet per minute and is the best performance measure to use when comparing air compressors. Cubic feet is volume and the per minute is the rate or how fast, so in other words CFM is how much air the compressor pump can move every minute. According to Eaton Compressors where I bought my compressor the 19.5CFM @ 100psi value is an actual measured CFM value. The larger air tank is just like having a larger gas tank on your truck, you can drive longer before you need to refill the tank. I learned a lot on air compressors and how to compare them by reading the info posted on Eaton's site. Here's a link to Eaton's website and specifically to the compressor that I bought. Read the supporting text and I think it will answer a lot of your questions.

http://www.eatoncompressor.com/catal...747/172993.htm

 

[QUOTE=cujo8]CFM = cubic feet per minute and is the best performance measure to use when comparing air compressors. Cubic feet is volume and the per minute is the rate or how fast, so in other words CFM is how much air the compressor pump can move every minute. According to Eaton Compressors where I bought my compressor the 19.5CFM @ 100psi value is an actual measured CFM value. The larger air tank is just like having a larger gas tank on your truck, you can drive longer before you need to refill the tank. I learned a lot on air compressors and how to compare them by reading the info posted on Eaton's site. Here's a link to Eaton's website and specifically to the compressor that I bought. Read the supporting text and I think it will answer a lot of your questions.

www.eatoncompressor.com/catalog/item/504747/172993.htm[/QUOTE]

Thanks for your explaintion, but I did know that. What I was trying to say is I dont know the effect on the busness end 2cfm would make. That was the difference between your porter and my kobalt. I cant see a cuft foot of air.
Thats what I was kinda getting at. $400 buys you a 60 gal compressor $200 buys you 150-200gal tank if you look for it. That gives you 210-260 gals of air. I dont think I could ever stay ahead of that at my place. So far I have'nt gotten ahead of my 60 gals yet but I do forsee that it could be done. Then I will add a tank. I thought you was saying your eaton was 20cfm at 90 psi. I dont know what the extra 10 psi would do,, I just have'nt see it advertised that way before. I've only seen it as @90psi\@40psi.
Dont get me wrong I'm not saying anything about big compressors. Just my personaul budget tends to find the same performace alittle cheaper. When I say same performace I dont full blown I meant actual used. I wish I had a way to test my theroy. I think a 60 gal tank w/ a pump 10cfm or larger w/ 60gal tank or larger will do just as good as a shop model compressor on the actual busness end.

 

Here's a good way to look at, If you have an air-tool that uses 15CFM to operate and your compressor pump is able to produce 10CFM, you'll be using more air than your pump can produce. The larger tank only buys you time before the pressure drops below an acceptable/usable level. On the other hand if you're using an air-tool that only uses 8CFM that same compressor will be able to keep up with demands of the tool. If you ever do media blasting with your compressor you will find out what I am talking about in short order. You'll notice if you go out to purchase a media-blasting device that they offer different nozzle sizes depending on the size (CFM Rating) of your compressor. For your size compressor you would want the smallest size tip, so that your compressor will be able to keep up. The smaller the tip the longer it takes to media blast your project. That may be not much of an issue if your doing small pieces like a water pump pulley, but when your blasting a truck frame you'd think you could read "War and Peace" quicker w/o your reading glasses than finish blasting this truck frame :-). Even with the smaller tip size your compressor will run continuously while you are blasting and most compressors were not designed to run continuously. Your compressor will not last you too long if you treat it like this very often. You'll find when you run any compressor for long periods of time that they get very hot and this will also cause a lot of water to condense out in your compressor, pipes, and hoses. This is not good for your tools, paint job, and makes media blasting a real PITA.
I agree with you that most compressor manufactures usually give the compressor CFM ratings at 90psi, so I don't know why Eaton gave my compressor a 19.5CFM @100psi rating. That is why I tell people that my compressor delivers 20CFM@ 90psi, so as to not confuse the issue, but in reality it is probably a little higher than 20CFM.
I do understand that money does not grow on trees, so you sometimes need to compromise a little and buy as much compressor as you can afford, but you also need to realistic about how much compressor you really need. From what I've read your Kobalt compressor is meeting your needs, so you have bought the right size compressor for your needs. My needs have been changing over the years, my first compressor was a small 110V 20gallon Campbell-Hausfeld compressor and I used it for more than 10 years before my needs changed and I replaced it with the 220V, 60-gallon Porter-Cable. I had the P-C compressor for four years, but once I started media blasting I quickly learned that I needed the larger compressor. If money was no object I would have bought an even higher CFM rated compressor, but I am happy with my compressor and this will probably be the last compressor I will ever buy. I have 3 frameoff restorations going on in my garage, so I felt I could justify the bigger compressor.

 

Its easy for me to "justify", Pretty much I have 2 rules #1 being if I just want it then enough said. #2 if it saves me money or makes me money.
I agree and you can know/understand{I'm not sure how to word it}. You get the compressor that meets the needs of your tools. I think doing ot backwards might get you into trouble. If you went and bought a 20 gal delivering 7.2 cfm @90 psi thinking you'll just shop and find tools that fall under that rating I'd say you would be either not going to be doing very much other than tires, nailing, or some drilling, or setting your self up to buying another compressor.
Its real simple if your tool calls for 20cfm thats what you get. If you already have 11.5 cfm you try real hard to stay w/ tools in that spec or try to bump what you have or suck it up and buy another one.
It sounds to me youfall under the needs of a shop running a couple bays at a time.
As far as buying your time, 200 gals of air buys you alot of time. In the end it might not be enough for you.

 

I worked many years for a company that used air compressors as part of our systems. These compressors worked hard and usually had to run near 50 percent of the time day and night. 365 days of the year.
We used mostly IR and Quincy. The Quincy was far superior.

 

My IR 6/80 from TS has been in service since 1999. Great compressor!

Been through a couple regulators, but the unit has worked great.

 

Adding tank capacity is not a cure-all for a smaller compressor. While it's true it will extend the time you can pull X cuft/minute, it takes some amount of time to fill it to begin with, and as you use it, the capacity diminishes. Example: Round figures you have a compressor that delivers 10 cuft/min actual. You pump up a 20 gallon tank to 200 PSI. Then you start drawing 10 cuft/min at 90 PSI. When the tank pressure drops to a given PSI, say 160, the compressor kicks in and delivers 10 cuft/min. As long as you keep drawing air, the compressor will not build pressure, because you're taking it out as fast as the compressor is putting it in. Now increase the draw to 11 cuft/min. The compressor will now again kick in at 160, but the tank pressure will slowly drop because you are drawing more than the compressor is replacing. When the tank pressure eventually drops below 90 psi, it will no longer deliver 11 cuft/min, but will drop off to 10.


Now, double the tank size to 40 gal. At 10 cuft/min draw, the above is the same - draw pressure down to 160, and compressor kicks on, and runs at 10 cuft/min as before, However, if you start at 11 cuft/min the only difference is how long between the point where the compressor kicks in (shorter interval until it does), and where you drop off to 10 cuft/min (longer interval than with 20 gal. End result is that by adding the additional 20 gal capacity you have extended the run time at 11 cuft/min slightly.
In summary, if the draw is only a small amount above the compressor output, and you add 300 gallons fo tank capacity, the time you can operate goes up, and if the load is intermittent, will allow the compressor to catch up, and the extra demand can be met with the extra storage capacity. But in continuous
operation all you gain is an extension of the time before cuft/min falls off.

 

On the air compressor question. Northern Tool has good pricing on made in USA IR compressors. I don't know about pumps made in China, I haven't seen one. Some machines had pumps made in Italy. No TYPE 30 compressor I have seen has a Chinese pump. A good 5 hp 2 stage compressor with an 80 gallon tank should handle most peoples shop needs. They put out 16 to 18 cfm usually. The 7.5 horse units are good,but you really need to be sure you have good 230 volt power to run them. The starting current is really high and if the voltage dips it will eventually burn out the motor. Don't use horsepower as the determining factor. Look at the cfm at the pressure you want to run. I've seen machines called 5hp that were actually only a 3hp machine. Sears used to be famous for that. They rate their power tool horsepower at the point right before the motor melts. As far as pipe. NEVER use pvc pipe for air. UV embrittles it and it is like a hand grenade when it lets go. People have been seriously injured by the flying fragments. They will penetrate a sheet rock wall under the right conditions. Black iron is good, but it will rust and rust is bad for tools so use point of use filters to take it and water out, copper is great and easy to install, but it has gotten so expensive that you might as well use gold. There are a number of anodized aluminum piping systems out there. We sell one under the IR name, but it is really pricey as well

Gary
Ingersoll-Rand
Master Technical Rep
Air Solutions

 

The IR compressors that are sold at Tractor Supply have the Chinese pumps on them. I found this out after I took the part#'s I got off the IR compressors I saw at TS and I went to the IR Website and I could not find any compressors on the site that matched any of the numbers. I then called a IR rep in Syracuse NY and asked him about these TS IR air compressors and he told me the these Tractor Supply IR air compressors had Chinese pump castings and these lower cost IR knock-offs were made specifically for places like Tractor Supply to sell. He told me to go with the Type-30 style US made IR compressor and steer clear of the Tractor Supply IR compressors. The thing is this whole experience turned me off towards IR, especially when the IR rep failed to get back to me with the quote I asked for 1.5 weeks earlier. As you know I ended up buying a Eaton compressor out of Eaton OH. The funny thing is I later find out from another person that the Eaton pumps are also made in China ;-( Maybe it's a non-issue since the compressor has been working great for me and I'm still quite happy with my purchase. I always try to buy US made products when I can, but it is getting harder and harder to do so. I figured the Eaton compressors were an all US made product, since it was coming from Ohio.