I am finally going to make the plunge on a compressor. This will be for home use and I will be using it as I go through my '53 F100. Besides tools, what else is needed for a compressor. I saw a CH at Harbor Freight, it loked like a pretty good unit. 3 Cylinder, 60 Gallon, 13.5CFM @90. Would this thing need a mag starter (that seems to be an option). Initially I'll be using it for sanding and eventully paint (primer). What would be other items to go along with it? Pressure regulator? Oiler? Filters?

I'm also considering a Ingersol Rand unit at Northern tools (2 Cylinder, 60 gal, 11.5 CFM @90), and also saw a 2 Stage General Air (1 Cylinder, 5HP rated, 60gal, 13.5 CFM@90).

At this point I am leaning towards the CH. They are all about the same price.

 

If you plan on using tools that have high air consumption like sanders, die grinders etc.., I would recommend a 2 stage. The reason for this is they'll fill up quicker thus take breaks more frequently and keep up with your tool a lot more. Though they are more pricey this will prolong compressor life. If you opt for a single stage I would go with 80 gallon tank if you have room for it. IR make great quality units. Oh and an obvious choice would be with an oil base.

But I'm sure others have good ideas also.

Madmike33

 

I would look at something with a minimum of 15 scfm@90, preferably more. Mine is 220V, 80 gal, 15.5scfm@90 psi, and with my cut-off tool, sander, or sandblaster going, the unit runs frequently. I almost wish I had gotten a bigger one.
Oh- you would also need a regulator, and a GOOD drier. Add some quick connect fittings, hoses, etc. for a basic setup. And of course, power.

 

Thanks! Is a regulator used with all tools, or just when painting? I wonder about the mag starter. Is that a nice to have or a must have? Why would an electric motor need a starter? (probably a dumb question).

 

This is the one I plan on getting.
http://www.lowes.com/lowes/lkn?actio...60V&lpage=none

 

A magnetic motor starter is a big relay, usually combined with some sort of overload sensor. The relay coil is driven by the pressure switch. When the pressure switch calls for air, the relay coil closes the contacts and powers up the motor. When the pressure switch is satisfied, the relay coil is de-energized and the contacts open, powering down the motor. The overload sensor protects the motor by opening the control or power circuits if they sense sustained current in excess of the full-load-amps of the motor.

Motor starters are essential for three phase motors and bigger single phase motors. At the 5HP level, it is possible to get by with the pressure switch directly controlling the motor (no relay). Overload protection is provided by a thermal sensor inside the motor itself.

I would consider the magnetic starter the more robust solution. The pressure-switch controlled designs may give adequate service for consumer grade hobby models.

A good sized regulator right at your compressor is a good idea if you have a two-stage unit and want to run it up to the full 175 psi. Otherwise, the shop air lines and everything attached to them is subjected to the full pressure. Some things aren't rated for that high a pressure.

All two stage compressors have at least two cylinders. There's no such thing as a "one cylinder" two-stage compressor. It may look like only one cylinder, but if you examine it closely, you'll find that it has two cylinders (one large and one small) in the same block and head. The output of the big cylinder goes to the small cylinder and the output of the small cylinder goes to the tank.

Put a ball valve right at the output of your compressor tank. When you leave the shop, you can shut off the valve and trap the air in the tank. Shop air piping and quick connects all tend to leak, and will bleed down the compressor over night. You then have to wait to pressurize the tank before you can use air in your shop. With the ball valve, you flip on the electrical switch and open the ball valve, and you instantly have air available to fill up a tire or operate that impact wrench.

If the compressor is to be operated at temperatures below about 40 degrees, you should consider a crankcase heater.

If you plan to put the compressor in the same space as where you will be working, be advised that the consumer models are really, really, incredibly, disgustingly LOUD. They usually are designed with small pumps spun really fast. This would give unacceptably short service life in an industrial setting, but is OK for hobby use. A good example is my 5HP Ingersoll Rand 2340L compressor. It has what is actually a 3 HP pump spun faster than normal by a 5HP 3600 RPM motor and a 2:1 pulley speed reduction. It has given me reasonable service (at 14.8 CFM it is just barely adequate for sandblasting). But it is LOUD.

I resurrected an older compressor that came with my farm. It has a 5HP 3-phase motor running at 1800 RPM spinning a big two cylinder pump through a 2.5 to 1 reduction. After working next to the 720 RPM of the older compressor, it is tough to go back to the other shop and listen to the IR screaming its head off. It's much like the difference between the pleasant throaty rumble of a big block V8 and the obnoxious blaaat of a 4 cylinder rice-mobile. Both solutions get the job done, but the slow turning compressor just sounds happier doing its job.

 

i put a wix filter and dryer on my compressor. the filters are awsome

Matt

 

Your probably right about the cylinders. This is the one I was refering too:

http://www.harborfreight.com/cpi/cta...emnumber=93274

The IR I was looking at is here http://www.northerntool.com/webapp/w...11720&R=211720 (can't link directly to the page, it's the first one when you click the compressor link). Seeing now that it is rated at 18CFM@90 makes it a bit more attractive (along with the free shipping). Need to spend another $75 for the startup kitfor warranty purposes.

Don't have a link for the CH as I can't find a 3 Cylinder on the web.

Great info Fefarms! Thanks!

 

The US General looks to have a two cylinder two-stage Chinese made pump. If it is a Fu-Shen pump then it may not be too bad. It probably has a Chinese made Emerson motor. Probably has a mag starter built into the connection box on the side of the motor, hence you don't have to put one on the wall. Typical Chinese clone product -- it might give you good service or might break after 500 hours.

The IR SS5 is a single stage. On IR's web site, they rate it at 18CFM at 40PSI, not 90 PSI. I would expect the IR to be closer to 16 CFM at 90PSI, given the 40 PSI rating. I don't know where Northern is getting their figures. 30 amps at 230 volts for the motor is a real honest-to-god 5HP motor. The pump may be US made, or may be made in Taiwan or China under US supervision. The supervision makes a big difference in many Chinese goods. The belt reduction ratio looks to be 3:1 from what I can make out from the picture. It is probably quieter than mine. IR used to buy their motors from Baldor, an old line U.S. vendor. I've heard they may be using Emerson motors now. The single stage will run hotter than the two stage and will have more of a tendency to "make water" in the tank, especially in Austin. At 60 gallons and 135 PSI you have less reserve capacity than with a two-stage model and the same gallonage, or a single stage model with an 80 gallon tank.

You might watch Craig's list and/or ebay and/or auctions for used models that you could pick up locally. I got a 7.5 HP, three phase, two-stage, three cylinder monster that way for $400. Supposed to be 26 CFM at 175 PSI, though there is still "some assembly required" to get it working.

 

Thanks again fefarms. I have been watching auctions (although only recently). Are the Fu-shen/Emerson pumps marked some how (they had one of these at the local store). General Air has a 2 year warranty on this model, but as I read it, if something goes wrong you have to pay to ship it too them.

 

A Fu-shen pump has the letters F/S embossed inside a triangular emblem cast right into the crankcase. Emerson motors will say "Emerson Electric" on the data plate.

One big advantage of IR over general is that you should be able to get parts and support locally. But it is often cheaper to replace a whole component. Think of a compressor as a pump, a motor, and a tank. Each component should cost about 1/3 the price of the compressor, although the tanks tend to be priced so high that the compressor is junk if the tank rusts out.

 

Dual action sander, Die grinder, Drill, Chisel.
Not to mention the fastening tools... brad nailer, stick nailer and 90 wire stapler. Very handy and they all plug into the same source. The air sweeper is handy for blowing the garage out without moving anything.

I spec'd a pump big enough to run 2 D.A.'s and also no spark on the startup incase I was painting or working in closed quarters. Ended up with a 4 lung emglo pump belted to a grain elevator motor on top of a 30 gal horizontal tank. Probably 600 invested but boy does it go. Single stage and I set it up for constant run or cycle start. Love it.

It's nice working with good stuff. It makes for an enjoyable time fixing and building.

Peace

 

Thanks again all. Based on what I have read it does sound like a 2 Stage is the way to go. Granted a General Air may not be tops on a compressor wish list, but the specs fit the need and it is in the right price range. I'm thinking if the pump does go out (hopefully I would get 2 years out of it), I could always replace it with something more desirable. At this point at least, I think I am now leaning towards that one.

 

That's good, I'm pretty sure you're not starting up a body and for that reason I think that is a wise move without breaking the bank. Besides the 2 stage is in many ways the better way to go anyways, no matter it's rating. That will still make for a better compressor than most of us have anyways.

Have fun!

Madmiike33

 

John,
It sounds like you are getting plenty of good advice about the compressor and tools. Don't forget about the piping.

You'll need to have a good dryer and filters and a way to drain any moisture out of the system. Also, a pressure regulator off the tank will keep a constant pressure in your piping system. The ball valve at the tank outlet upstream of the regulator is a good idea. Drops should come off the top of the line and then turn 180 degrees down to your connection point.

Use copper pipe for the piping. Yes, it may be a pain to solder, but its worth the effort. Steel pipe will corrode on the inside from the water and the rust will be a problem. Copper is always used in commercial air piping systems.

DO NOT USE PVC or any other type of plastic pipe!!! Plastic pipe will fracture in compressed gas service and the sharp pieces are dangerous missiles that can cause serious injury. I speak from experience, as I am a professional engineer who designs this stuff for a living.

Send me a PM if you have any detailed questions.