Where is true information on air compressors?

I am looking for an air compressor for my workshop. The first task will be to drive nailers to build a shed and then spray paint the shed. After this the compressor will primarily be used to run nailers a vacuum clamp and press system (4.2 cfm advertised requirements) the occasional air tool (sanders, nailers, impact wrenches) and some finishing. I don't have a lot of 220 volt access or abundant space. The current benchmark I am considering is a Campbell_Hausfeld direct drive oil less 6.5 HP 28Gal compressor at Lowe's $270. The problem I am having is finding real information. I am under the impression that the advertised capacities are like a politicians promises. and I can find almost nothing on what the duty cycles of various compressors are. The CH web site is sad. I have done google news group searches. Does anybody have a good source of experience or information? Thanks in advance Marty

Reply to
rmball28
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Reply to
Dan Parrell

Reply to
JGS

The CFM and pressure specs are generally fairly accurate, the HP ratings are grossly overstated. The compressor cycle time is dependant on the air use of the tool and the size of the tank. Ultimate maximum continuous flow is determined by the compressor itself.

Greg G.

Reply to
Greg G.

This is a vacuum system that uses a compressor and an air ejector to produce a vacuum ?

IMHO, don't do it. They're hungry for air and awfully inefficient. In practice this means sharing your workshop with a fairly large compressor and having it running near-continuously. It works, but it's an unpleasant way to work.

_Much_ better is to find a vacuum pump. You can buy one (a _very_ rough vacuum is adequate) or you can eBay a S/H lab vacuum pump (you can get them for about $75 locally). Because this is more efficient (it's not using an ejector) it's a lot smaller and thus quieter, for a given vacuum capacity.

Make sure you get something that's happy pumping down a closed vacuum chamber all day. Fridge compressors can be rigged to work as vacuum pumps, but they start to arc-over if they're left running closed off.

As for nailers, then almost any compressor can run them. Doesn't need much air. Random orbital sanders are one of my favourite air tools (for woodworking) and they're a bit thirstier though - depends on the quality too.

-- Klein bottle for rent. Apply within.

Reply to
Andy Dingley

Reply to
Wilson Lamb

Marty,

Here is the scoop on air compressors:

1 true HP will make 4-5cfm @ 90psig for an oil-lubed compressor. The ratings you will see on the el-cheapo units are peak HP or locked rotor HP and have nothing to do with true running HP. Motor Mfg's do not make 6.5 HP motors! These are probably 2-3 HP. Large tanks can provide extra air for peak demands, but cannot make up for large continuous flows. Also, taking oil out of a compressor makes it noisier, reduces the output cfm/HP, and cuts the life expectancy of the unit. Duty cycle for an oilless is 50% at best, vs 80-100% for an oil-lubed compressor. That said, you do have to remove the oil from the air stream with good filters. Most paint sprayers need >10cfm, so you are looking at ~3HP of real compressor. Check
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for SS3L3 shop compressor. makes 11.3cfm @ 90psig for 3HP(7.9 peak) 15amps 230V. 5year warranty and 100% duty cycle. Plus this unit is worth rebuildingwhen the time comes.

Let me know if you have any more questions.

Best Regards,

Momo

Reply to
momo99

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