What can my air compressor do?

[rjvjeepster]

Picked one just like this off of CL a few years back for $150 or something with a hose and dryer.
http://www.machinerymax.com/Event/LotDetails/5429447

(DeVilbiss Air America 5hp/20 gal) 7.1 CFM @ 90 PSI and 8.7 @ 40 PSI.

I want to start getting more air tools but won't invest in them if this compressor isn't up to the task. From my limited understanding, as long as the tank has enough air in it, the CFM doesn't matter. The CFM is just the rate at which it refills and matters when you deplete the tank enough as then you'll have to wait that much longer till you can use the tool to its potential...aka the duty cycle?

Plans would be to use mainly an impact wrench, impact ratchet and possibly an air hammer.

Please correct me/ed-u-muh-cate me! Thanks!

 

[JazzBlueRT]

I thought it was impossible to get more than 2.5 HP from a 120v x 15amp outlet.

 

[Marctrees]

Well, the "5 hp" is bs, it is more like a 1.5.

Nevertheless, it wiil be a good start in your shop.

You paid more or less what it's worth.

From this, you will figure out if your needs validate more. Marc

 

[Marctrees]

And, for many, really most folk here, that is a smallish tank for anything over pretty light use.

But hey, it's an ok start. Marc

 

[Schurkey]

I USED TO HAVE THAT COMPRESSOR. Well, one just like it, anyway. Same brand, same decals, same everything except I think it was advertised at an exaggerated 4 hp. (Not real clear on the HP rating. It was in 1997, August or September-ish.) I removed the regulator, because I never needed less than every PSI it could generate.

It would run my air hammer for about three seconds. I was trying to remove the ball joint rivets from my new-to-me 4x4 pickup. Took me all damn day. Did fine with an impact wrench pulling lug-nuts, but that's not really a challenge.

Traded the compressor for a rusty '66 Toronado. Bought a "real" 5 horse single-stage, 60 gallon tank which worked acceptably well for everything except the die grinder. Got damaged in a fire.

Now I have a "real" 5-horse@1725 rpm, two stage, 80-gallon job that does all I need, if not all I want.

 

[disston]

Better than one of those "Oil Less" models.

 

[Bighead38]

Used a husky model that looked identical to yours. It ran the entire time but did keep up with 2 nail guns for the most part. It was able to fill a flat tire but once again it was running. I don't think it could run an impact gun for more than a couple seconds at a time. I think it would have no chance trying to run a sander or a grinder wide open. It might work for a couple seconds before running out of power.

 

[AA/FC]

I thought it was impossible to get more than 2.5 HP from a 120v x 15amp outlet.

Correct. But that doesnt sound as good as saying 5 horsepower when marketing a product. Just another case of false advertising. Lol.

120 volts, at 15 amps = 1800 watts available from your typical residential electrical outlet..... 746 watts is equal to 1 horsepower...... which makes for a total of 2.41 horsepower.

Now, lets say you're lucky and you have a 20 amp circuit in your garage..... it's still only 3.21 horsepower.

These are general figures and they do not include inefficiencies, voltage drops, etc, etc. Your mileage may vary...... but either way, 5 horsepower aint happenin'.

 

[Ole Slewfoot]

I have that in the garage too. Move 2 wires and you can plug it into 220. It is a continuous duty motor. Still not ideal for heavy impacting, so you will want a gun that hits pretty hard. Multiple recharges for 240 ft/lb would get old fast. runs my nailers, runs plasma, runs blower no problem. I used it for the ball joints on a friends Dodge 3500 and it was fine.

 

[sberry]

A 1 hp motor draws about 12A. 746 watts is an exact calculation, with losses it takes 2x that to make air, most machines do not draw a full 20,, the circuit it's on is different than the draw.

 

[gungatim]

my first compressor was a CH 2hp 20gal. model with similar specs. It did everything I needed for many years before I upgraded.

ran impact and other air tools no problem; with the exception of DA sanders and cut off tools. those will run a minute or two and you have to let the compressor catch up. you learn to work around it.

I painted many vehicles with it, even some mild sandblasting, though plumbing an extra tank will help extend the up time.

I upped my regulator to 125psi, it was set from the factory around 100 and that helped. do so at your own risk however...

 

[theoldwizard1]

I thought it was impossible to get more than 2.5 HP from a 120v x 15amp outlet.

Actually, 1.0 - 1.5 is more realistic and with a hard starting appliance like a compressor, you probably should have a 20A circuit.

 

[rjvjeepster]

Thanks for insight everyone! So it sounds like it's about at capacity to run an impact unless you're really going ********.

 

[theoldwizard1]

I have a 2hp (240V) compressor very similar to that. It will run a cut off wheel, but not for more than a couple of minutes. It will run some die grinders.

It is not going to run most sanders, or sand blasters.

 

[sberry]

7.1 at low pressure is the max from the circuit. At those pressures it is a pinch over 4 cfm per hp, maybe 5 in that type of comp.
The rule of thumb for a 2 stage is 4 per hp.