Air compressor CFM ??

[Bowtie68]

Shopping for a new compressor. After reading a few threads on here it seems that CFM is the goal. I will be using this in a home shop/garage mostly for automotive use. I want it be capable of running DA, grinder, cut off wheel, sand blaster, ect, ect. Ive narrowed my search down to two options both from Ingersoll Rand. I was convinced that bigger is better until I looked at the CFM. These are the two options...

CFM @ 90 PSI: 18.1
Duty Cycle: 100%
Air Outlet Size: 1/2 in.
Style: Single Stage, Twin Cylinder
Grade: Commercial
Running HP: 5 HP
Maximum Pressure: 135 PSI
Pump Type: Cast Iron
Tank Size: 60 gal.
Manufacturer Part Number 48671770


Running HP: 5 HP
Duty Cycle: 100%
Air Outlet Size: 1/2 in.
Grade: Industrial
Maximum Pressure: 175 PSI
CFM @ 90 PSI: 15.8
Tank Size: 80 gal.
Style: Two Stage
Manufacturer Part Number TS4N5

The 60 gal has a higher CFM @ 90 18.1 vs 15.8. The 80 gal seems to be better in all other categories, max pressure, two stage pump, bigger tank. I guess my main questions is higher CFM worth the smaller compressor?

 

[wanderer]

Either one will probably perform for you for a long time. The bottom one is a two stage that goes to 175 psi which is probably more than you need. It will actually provide significantly more reserve because of the larger tank volume and higher pressure. Given the minor difference in CFM output I would be inclined to get the lower one price were equal or similar. Given your needs you will probably have more usable air out food for the shorter periods you needed then with the other.

 

[lis2323]

Depending on your sand blasting needs/expectations you may be disappointed with 18 CFM.


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[Bowtie68]

Depending on your sand blasting needs/expectations you may be disappointed with 18 CFM.


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Saying I may be disappointed because that wont be enough? I dont have a sandblaster yet but it would probably just be a smaller cabinet style.

Ingersoll Rand SS5L5 5 HP 60 Gallon High Capacity Air Compressor $999

Ingersoll Rand 80-gal. 5 HP Two-Stage Industrial Air Compressor $950

 

[lis2323]

Bowtie my 2 stage Atlas Copco 5 HP is rated at 23 CFM and I feel more CFMs would be nicer for my blast cabinet.


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[joe_padavano]

I'll second the thought that you can't have too much SCFM for blasting. The problem with too little SCFM is that you will be forced to run a smaller nozzle in the blast gun to keep pressure up, which dramatically slows your blasting. Trust me, that gets old in a hurry. If you're thinking of spending $1000 or so, consider buying a used industrial three phase compressor and swapping out the motor for a single phase one. I got a 7.5HP single phase Leeson for about $600. Put that on a compressor with a Rolair K30 compressor pump and it doesn't even breath hard when I media blast.

 

[SGKent]

you also want to look at the CFM at the working pressure. Max pressure is what the machine will build to and store, it isn't necessarily the pressure the CFM is rated at. I'll take a 15 CFM at 125 PSI compressor all day over an 18 CFM one at 35 PSI, even if both max pressures are the same. I have two near identical Devibiss models. One has much higher top pressure ratings but they are identical otherwise. The only real difference is that the higher rated one has a bump inside the head that raises the compression ratio a little. They both are identical speeds, cylinders, and motors. Both put out the same CFM. It's like fooling yourself that you are eating less these days because you got a bigger spoon, and take less bites with it.

 

[Shadowdog500]

Saying I may be disappointed because that wont be enough? I dont have a sandblaster yet but it would probably just be a smaller cabinet style.

Ingersoll Rand SS5L5 5 HP 60 Gallon High Capacity Air Compressor $999

Ingersoll Rand 80-gal. 5 HP Two-Stage Industrial Air Compressor $950

I have the SS5L5 for about 7 years now and like it. It more than keeps up with my dee blast blast 34 blast cabinet(about same size as big HFCabinet see below). The first time I used my cabinet with the SS5L5 compress I was thrilled when the compressor actually shut off with a full charge while I was still sand blasting.

I also use it to blow out my sprinklers every fall. The compressor maintains 90PSI at the outlet the entire time as my sprinkler system timer does two minutes on each of the five zones. (Before Someone says something, I do have a separate regulator set at 40PSI connected just prior to the sprinkler system. see photo below)

 

[rbgearz]

I recently bought an E Max Silent Air compressor. Wanted something that was going to do anything I needed and was not disappointed. 80 gal. tank, 7.5 hp single phase, 31 cfm @ 90psi. Quietest compressor I've ever had. Pricey but well worth it. Made in USA too!

 

[Shadowdog500]

Bowtie my 2 stage Atlas Copco 5 HP is rated at 23 CFM and I feel more CFMs would be nicer for my blast cabinet.


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Do you have the 7.5 HP?

The 5hp has 15.3CFM at 100PSI
https://www.aircompressorsdirect.co...iYNoXuGvPSMZrUIK5Yi24vtUetXKOQCgaAg3pEALw_wcB

 

[sberry]

How much you gonna blast. This is a hobby? If time is money and this is steady, daily then more enough power is priceless. The standard here is 5 hp 2 stage for auto body work.

 

[Bowtie68]

Thanks for all the replies, and people say forums are dying lol.

This is just hobby in my shop at home. I do mostly automotive stuff.

 

[lis2323]

Do you have the 7.5 HP?

The 5hp has 15.3CFM at 100PSI
https://www.aircompressorsdirect.co...iYNoXuGvPSMZrUIK5Yi24vtUetXKOQCgaAg3pEALw_wcB

5 HP 290 psi maximum working pressure, but I stand corrected. 21.4 CFM. [emoji851]

 

[Shadowdog500]

5 HP 290 psi maximum working pressure, but I stand corrected. 21.4 CFM. [emoji851]

What model is that? https://www.atlascopco.com/content/...LE-LT-LF-LB_antwerp_leaflet_EN_2935084649.pdf

Looks like it may be 3 phase.
I’m sure it wasn’t inexpensive new.

 

[lis2323]

We bought it new for the farm in the late 1970’s. I can’t recall for certain but I think it was under $3000 Cdn. Model LT7

I just sold this 40HP Quincy. 197 CFM

Decided it was too big for my blasting needs.



There’s a limit to what you need in a retirement shop. [emoji23]

 

[rburke65]

Go with the 2 stage compressor. Trust me....the small cut off wheel n the sand blaster will eat up the air. Buy the best one you can afford.....even more than you can afford. It’s like buying power tools and not having electricity. It will be the heart of your shop.

 

[bad_idea]

I would get the two stage. CFM of the pump is important when the pressure in the tank drops below working pressure. Until that moment, CFM of the air hose is the only restriction. A higher tank pressure means a larger reserve of air. The compressor will also be off for longer periods of time, meaning more peace and quiet. Also look at the pump RPM, lower RPM means the pump displaces more, isn't working as hard and the compressor will be quieter.

 

[sberry]

Ya, that 40 would be great for business. There is a show, AmEric Restoration maybe, Rick? Wife with ************,, anyway they bid stuff with lots of blast. Their rates are too low but they losing some time with too small blast equipment best we can see. That's really nice. Flip switch. Reliable. Even portable to some extent, great in factory.

 

[sberry]

I would get the two stage. CFM of the pump is important when the pressure in the tank drops below working pressure. Until that moment, CFM of the air hose is the only restriction. A higher tank pressure means a larger reserve of air. The compressor will also be off for longer periods of time, meaning more peace and quiet. Also look at the pump RPM, lower RPM means the pump displaces more, isn't working as hard and the compressor will be quieter.

Great explanation, I was wondering how to word that simple, once it drops below working pressure,,,, of course the more it drops the more it effects loss, kind of compounds.

 

[sberry]

Of course as the pressure drops the loss compounds,, or becomes more, there must be formula for it.

 

[Bowtie68]

Thanks guys for all the advice. I have decided to go with the 80 gal two stage. Now just to find the time to go get it and hook it up.