Is 6CFM enough for an air compressor for me?

[t.ruckus.rex]

Have a little dilemma.

Current shop is one man operation with just me(!) and 600sq feet of machine shop space.

I have a 5hp Quincy 325 right now. But the thing is really noisy and takes up a a large amount of room. Between that and the three phase converter I can barely hear myself thinking.

I have a set of Gast dry air compressors, two at 3/4HP and 3cfm each. This is continuous CFM too. They are about 1/10th the space and noise of the Quincy and can be mounted way up on the racks too.

Biggest air tool I run is a 1/2 air drill and 1/2 impact. Its just me in the shop.

I'm thinking of selling the Quincy 325 and just using the two gast compressors.

Any opinions?

Compressors in question.

 

[larry_g]

Are you also thing of a receiver to run the air into? I would suggest that you plumb the outlet of the gast units into the Quincy tank and see if they will do what you need for a couple of months. You can do it but are you willing to put up with the wait times if your using more air than those two can deliver?

lg
no neat sig line

 

[shampoop]

For general mechanics stuff I don't think CFM is a big issue. The biggest issue IMO is whether or not the entire system has high enough pressure and flow in order to allow your 1/2" impact gun to be working at it's full potential.

I have an Ingersoll rand 2131qt which is in the middle of the range of their 1/2" guns.
http://www.sears.com/shc/s/p_10153_...01&srccode=cii_17588969&cpncode=33-79319013-2

My personal home compressor is a 120v 20A 120psi unit with probably 20-30 gallon tank milton v series high flow couplers all around and a 25' air hose, yet it only gives my impact around 65-75% of it's max power. The V series coupler did make a noticable improvement.

I've worked at a shop with a 60+ gallon 240v 120+psi unit that only gave my impact around 80% of it's max power.

But at big shops with huge compressers etc. even with the "low flow" air couplers my gun has TONS of power. 100%

My theory is that the most important thing is having a system at 150psi+ and enough flow to where when you hit the trigger, the pressure going into your gun never goes below 120psi. That's the most important quality.

Tank size and cfm matter more for when you're using a lot more free spinning (grinding) tools, painting, or something similar.

 

[RECox286]

If all you want to do is inflate tires, then the compressor set up in the picture will

do fine. You will run out of air pressure, and the compressor will not recover

or keep up with the tools you choose to use, and it will become frustration central

very quickly, b/c of the on again, off again (waiting) for the rig to "catch up".

JMHO, but from experience. IOW, give it a go, b/c a picture is worth ten thousand

words of explanation.

Uncle Bob

explain things

 

[cheechi]

If your existing compressor fits your needs and the only issue is noise, you will probably feel the difference going to lower CFM.

You mentioned it takes a lot of space but one possibility is to build curtain walls and put as much insulation between it and you as you need to fix the issue? Assuming you have the space and orientation to make that work, some noise reduction and enough air to work is better than a lot less noise and not enough air to work.

 

[bobcatdan]

At home I have 24 cfm and love it. At work, I am the only one at work and run 17 cfm. I use air tools only when I need them ie 3/4" impact and find myself waiting for it. From for a shop 24 or go home.

 

[transittech]

It depends on the airflow of the 1/2 gun/drill you are using.

More power (generally) = more airflow.

I have a 26 gallon tank and 4-5 cfm at home. Its plenty for my $20 HF special impact wrench, but when I bring my IR2135 home, its only got enough steam to change about 1.5 tires before turning on again.

6 cfm will prolly take forever to fill a 60 gallon tank, you might want to get a smaller tank while you're at it. Plumb into your existing tank and try it.

 

[KinzeMech]

6 cfm will prolly take forever to fill a 60 gallon tank, you might want to get a smaller tank while you're at it. Plumb into your existing tank and try it.

Roughly 10 minutes.

6cfm is not enough for any kind of serious usage. Also worth considering is how long those little pumps might last.

 

[sberry]

I agree, make some kind of noise baffle.

 

[srmofo]

plumb them into your existing tank and set them to come on sooner than your quincy. That way you have piece and quiet when you are just using moderate air, but still have the quincy to deliver the CFMs when the demand arises.

 

[haveissues]

My compressor is similar to your quincy and my shop is the same size. I improved the noise by mounting it on rubber pads (old cut up lawn tractor tires) and more importantly plumbed the intake into the attic. That made a substantial improvement unless you happen to be in the attic when it turns on.

 

[bsaint]

Get a better quality inlet. I have an oversize Solberg Filter assembly and its quiet. My wife says you cant hear my 1.5 emglo unit in the basement run.

 

[2oolhound]

The air intake as was mentioned is the 1st place to modify.

My fan shroud adds a lot of noise to my compressor. If I hold pressure against it I can knock off 10-15 decibels. It is screwed on tight but there is enough flex in it that it makes noise when it vibrates. I'n going to put rubber gaskets between it and the mount points and see if that helps.

I need to build insulated panels around it next. Not a big deal because it's in a corner so just 2 walls with access holes to the power switch, gage/regulator and drain.

 

[pipsters]

CFM output of the compressor is sort of meaningless with air tools on smaller compressors. I say that because what drives air tools is stored air - no real air tool will ever use just 6 CFM @ 90 psi when under load. You could have a 1000 gallon tank with 3000 psi and it would power an air tool the same as a 10 gallon tank at 150 psi as long as you are using the exact same regulated pressure, air line, and fittings.

What is more important in small 120v compressors is storage. More storage = longer run time at full power. I like the suggestion above to run these compressors in tandem with your main compressor. Use your main compressor to come on and fill the tank and run when under heavy load but these quiet compressors to run as you use and air ratchet or impact sporadically.

 

[joshmodelskidoo]

my compressor in my shed is a 6 cfm @90psi i believe and a 33 gal tank. its great as long as i stay away from the cut off wheel. although loud and it works i would go with something bigger like 10cfm @ 90psi and oil lubed

 

[theoldwizard1]

Biggest air tool I run is a 1/2 air drill and 1/2 impact. Its just me in the shop.

6 CFM is fine for a 1/2" impact. Depending on the drill and how much you use it (or maybe I should how long you use it), it could be an issue.

6 CFM would be very marginal for cut off wheel, sanders or most sand blasters. As mentioned, a large tank (> 30 gallons) would help a lot, but when you are out of air, recovery would be long.


(When they installed vinyl siding on my garage, the must have used 3" nails for the hangers, because at least 1" was protruding through the old wooden lap board siding. With no insulation or interior walls, the place looked like an iron maiden !! I only have a 2hp compressor with a 20 gallon tank. I think it is rated at 4-6 CFM @ 90psi. Using my cut off wheel on those nails, I would have to stop every 5-10 minutes and wait 5-10 for the compressor to build back to max pressure, 125 psi.)