Shop air advice needed

[Swede]

I hope this is on-topic enough for the CNC Zone. My shop compressed air system needs an upgrade. I am moving into a bigger shop (yay ) in a few months, and need to upgrade my compressor. Right now I am using a tiny little job that's really nothing more than a roofer's portable. I'd rather save my money for CNC stuff, so I am trying to do this cheap.

My demands are no more elaborate than mist coolant, simple air tools, etc. I'd like a vertical job to save on floor space.

Anyone have any experience with Harbor Freight's compressors? What is the advantage of a two-stage system?

Finally, would it be practical to add, say, a 15 to 20 gallon air storage tank (just the tank, no motor) onto my pancake compressor to add capacity? Would this help, or would the compressor cycle just as often as it does now, which is TOO often?

Thanks for any insights...

Swede

[nervis1]

I got a new AC a year ago from Home Depot, a Husky brand (made by CH) 7.5 hp (yea right more like 4, maybe less?) 60 gal. Feeds all my tools, blast cab, and VMC just fine. It was just under 1k from what I remember. 15 cfm @ 90 psi, takes up about two sq. feet of floor space, uses a 1 ph 220 30 amp breaker.

It's a two stage, with oil lube. It's been very reliable even in 100 + degree heat in the summer and 40 in the winter.


http://www.cnczone.com/ub...c;f=8;t=000039


Heres all you need to know thanks to Forrest Addy.

[Ken_Shea]

Dave you beat me to an exact recommendation, they have excellent prices and very respectable units. Swede with what you mention I doubt that you would need the extra storage, but it will not hurt, compressor will kick in less oftem but also for a longer period of time, personally I would prefer it kick in more often and then shut up quicker

[Swede]

That is a GREAT link, thanks guys! Off to Home Despot tomorrow. My poor circuit breaker panel cannot handle too much more.

P.S. the final "straw" was my new Trico Micro-drop system. From what I have seen so far it's really nice. No fog!!

[ViperTX]

Yeah either the 7.5 at $1k or the 5.? at $429 at Home Depot or Lowes....both seem well built one is a 2 stage and the other is a single stage 15 CFM versus 11 or so CFM and both are vertical units...so a 2 stage is generally a 2 cylinder and a single stage is a single cylinder pump.....save the portable for field use....*chuckle*

[Ken_Shea]

Yes Swede, if you can bite the bullet definitely get the greater CFM 2 stage, normally these have higher pressure and will pump up quicker, a big plus, I hate that noise

[kenlambert]

I went with one of the oiless type compressors with the 60 gal tank and 220 volt 6 HP motor it is going on Ten years old now .I used to have an auto repair shop so it has had a lot of usage and still pumps up quik and maintains 95# of pressure running my blast cabinate I gave 350.00 at sears

[Swede]

Did a bit of online search for both Lowes and Home Depot (Sorry non U.S. Zone guys - I always feel weird discussing U.S. merchants like Home Depot on an international forum). There is an obvious and big jump in price and capability going from 1 to 2 stage AC. I probably cannot justify the 2-stage jobs. This particular model looks good - nice, medium range AC for the home, not too small, not too big.

http://www.homedepot.com/prel80/HDUS...4+3966&pos=n24

It is one stage, 2 cylinder, oil lube, 60 gallon, 10.3 CFM @ 90. Changeable air filter. $429.

My new shop will be in a hangar, and looking into the future, and the types of activities I may be into, I can really see needing more compressor than this one. Darn it, this is probably one of those decisions that I may look back on and regret, not getting the better 2-stage unit.

I'll check out Lowes and Home Depot today and will report back. Thanks for the advice. One last question - Lowes features Campbell-Hausfeld compressors. They range from tiny jobs to bigger, 2-stage units. Any thoughts on Campbell-Hausfeld? (Leaning towards 2-stage... talking myself into it!!)

[ViperTX]

Swede...you could always purchase another unit and place it in a different part of the hangar. Also, I believe that when they say twin cylinder it is really a dual piston in one cylinder. The real 2 cyclinder units are V-twins.

[InventIt]

Dual and single stage compressors:

Single stage can be one or more pistons. The pump (compressor) intakes ambient air and compresses it in one stroke. The compressed air is then pushed into the holding tank.

Two Stage compressors: Have two or more pistons. One piston is large in dia and one is small in dia. The large piston intakes ambient air compresses it to about 90 PSI and exhausts that compressed air into the chamber of the smaller piston. The smaller piston compresses the air further to its final PSI and then into the holding tank. Usually there is a cooler in-between the stages to extract heat.

The advantage to two stage is higher PSI with lower HP req. and usually higher CFM ratings. When comparing units pay attention to PSI rating as well as CFM. CFM will drop off dramatically as PSI increases. So a unit rated 10 CFM at 120 PSI is much smaller then a unit rated 10 CFM at 175 PSI. Also, most of the better units run the pump at a slower speed, 900 – 1200 rpm, this means more air pumping and less wear with less heat buildup.

An air compressor is a life long investment. A good one will last a LONG time. Good units are usually serviceable as well. Get one that will fill your requirements into the future.

Anyway, all this is probably moot if your requirements are light duty or short term.

Whatever your decision, be sure to install a valve at the bottom of the tank to drain condensate.

[InventIt]

One more note, from what I have heard, USA made motors have 2x the power of their China made counterparts. A China brand 5hp is actually only 2.5 hp or less. I forget the reasoning for this but I think it had something to do with rating standards.

I have a Emco compressor with a 3hp GE TEFC motor that performs much better then my dads CH 5hp made overseas job.

[ViperTX]

Well take 746 watts for 1 HP and look at what the motor uses and you'll have the HP.....developed versus actual HP.