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Grex Sander-how many CFM

K

KEW

Joined
Jun 9, 2005
Messages
340
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Location
North Metro Atlanta
Grex's own specs say it only requires 2.2 CFM.

Is this correct. I'd appreciate it if anyone who uses this sander could share their thoughts on how much air it takes to run it.

I need to know if a 30 gallon compressor rated at 4cfm @ 90psi and 6cfm at 40psi would work.

Thanks!
 
grex

i use a 70 gal 7 hp works just great but i only use it for higher grits .
your compressor will work it will just run almost all the time let it rest now and then to cool down and keep an eye on the oil level.
 
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Kurt,
I use the Grex with my 5 HP Black Max oilless compressor rated at 9.1 CFM @ 40 PSI and 7.3 CFM @ 90 PSI with a 20 gallon tank and it basically never shuts off. If you know what an oilless sounds like when running you can understand that it is not fun. I am planning on moving my big 80 gallon compressor from upstairs in the garage down into the shop as it is quieter and has greater capacity, the portable can then go upstairs and take care of garage duty. Even adjusting the screw on the Grex has done little to slow its appetite for air, I think their 2.2 is a little off. It does do a nice job though!
Bill
 
Moving the Compressor

Bill,
I don't know your layout, but why not leave the compressor in the garage and just run a line to the basement? That way you'll never have to hear the noise. Just a thought!
KurtB:)
 
Kurt,
The woodworking area of my shop is below the garage and family room, 34 X 33, the floor is 14" of concrete. My turning area is in an ell that I built off the shop that is 24 X 36. Seeing that the big compressor is still sitting on the pallet that it was shipped on (never got around to taking it off) it will be easier to move it down stairs into the shop than drilling through the concrete. It will still be about 40 feet away from where I'm turning and be a lot quieter than the oilless. And one other fact is that my wife wants a pantry and the only place to put one is to go out into the garage and that is where the compressor now sits anyway. As I write this I'm thinking that I could have gone ten feet and ran it through the wall and down into the turning area. Oh well the pantry is scheduled to start soon.
Bill
 
Kurt, I've seen cfm requirements for the Grex all over the place, from the low you mention up to close to 15 cfm. :eek: I ran mine for a long time with a 27 gal Coleman compressor with an imitation 5 HP motor. While it worked, I would have to stop and let the compressor catch up from time to time. Now I am running it with an 80 gal IR and a real 5 HP motor, and even that will kick on if I really run the Grex. But it is rated for continuous duty, so it keeps up.

Bill
 
Not So Thin Air

Kurt,

Unless electricity is free where you live, or you use a lot of air for other tasks anyway, you might want to reconsider your plans for an air sander. Remember that with a compressor big enough to run the thing, you're spending real dollars to run a 3 or 5 hp motor just to spin that little 2 or 3" abrasive disc. Air tools such as this were designed for industrial settings running monster compressors with many workstations running many air tools. Even a smaller commercial shop running air tools is marginally inefficient outside of the automotive context with lifts, body work, and such.

If you're looking for a small orbital sander for turnings, consider the Metabo SXE400 [ http://www.allprotools.com/store/page310.html ] or one of the Sioux/Milwaukee angle drills (I use the Sioux 2,500 rpm). They will do a very credible job at less than a 100th of the cost to run and maintain.

I have a 12CFM I-R compressor, but I spray finish my furniture and turnings, plus I use air tools in the garage.

Just some alternative thoughts.
 
I have the Metabo SXE400. The head is bulky and the handle is always in the way. Unless there is some accessories for extending the sanding pad, it has limited usage on interior of bowls.

Gordon
 
Pad Extenders

Gordon Seto said:
I have the Metabo SXE400. The head is bulky and the handle is always in the way. Unless there is some accessories for extending the sanding pad, it has limited usage on interior of bowls.

Gordon
Click to expand...

Packard and others sell sanding pad extenders in various stiffnesses for velcro mountings that will give you up to an extra inch of depth with reasonable stability. Next time I'm at my friend's (who has the Metabo) I'll check to see if something more can be rigged without too much trouble. I use several extension shafts for my Sioux.
 
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I also have the Sioux 2500 RMP right angle drill. Mine needed a new cord just a few days after the warrranty wore out and the repair center Sioux suggested I use charged me a little over $35 to put a new cord on it--and took six weeks to do the job. All my other electric tools are Porter-Cable, some of which are nearly 45 years old, and I've never had to replace a power cord. In short, I think the Sioux is a good, maybe even unique product, but their service is expensive and lousy.

For the life of me, I can't see why Porter-Cable or Dewalt don't make a competing product.

I've been getting the AAW magazine for about two years. Someone told me that in an issue further back there were plans for making sanding pad holders of various lengths. I'd be interested in seeing those if they are available.
 
Gordon Seto said:
I have the Metabo SXE400. The head is bulky and the handle is always in the way. Unless there is some accessories for extending the sanding pad, it has limited usage on interior of bowls.
Click to expand...

Just yesterday I was sanding a bowl interior with a heavily overhanging rim with my Metabo. I turned a wood disk, 3" diameter x 2" with Velcro on each end. Viola~ a head extender. I put my innerface pad on the sandpaper end and it sands just fine.

BTW, I love the results using my Metabo on the exterior of turnings.
 
HF sells a cheapo "close quarters" VSR drill for $34, sometimes on sale for much less. The bearings are not terribly durable, but you can buy 4 or more of them for the price of a "good" one. Mine recently shorted between the power cord and the commutator, but no big deal to fix it myself.

Is difficult to see the logic of running a 5 hp compressor to do the work of a 1/4 hp (or less) electric tool.
 
Texian said:
Is difficult to see the logic of running a 5 hp compressor to do the work of a 1/4 hp (or less) electric tool.
Click to expand...

True, even without the noise problem. Not "green," at all. Once again, the flex system seems to answer the last two complaints particularly well, and sands like a dream. The Flex edge does fast curves, the stiff edge the slow. http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=150Sand-1.flv

Every time I see one of these threads about pneumatic or RO sanders, I like to look and see how many of their proponents insist that sanding slow is superior to sanding fast in other threads. :rolleyes:
 

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btw

MichaelMouse said:
True, even without the noise problem.
Click to expand...

Assuming that is the "noise" of the compressor of which Michael speaks, let's not forget the noise of the air tool itself. The Grex is listed at 80+ dB with a very annoying high pitch. Thus hearing protection is required unless you plan on going deaf early. In addition, if your shop is a stand-alone building with nobody else around, that's fine. But if your shop is in your home [basement - garage], plan on getting the family to wear protection and/or forego TV and other things while you're sanding your stuff. That'll go over real well. :rolleyes:

When I got my compressor rigged and piped into the basement shop, I was all set to start acquiring/using those nifty air tools. Picked up a 3/8" air drill and tried it out that evening. Didn't have anything near the torque of my cordless drill, ntm the corded tools, but did ok on smaller holes. However SWMBO promptly paid a rare visit to the shop to inform me that either she or that screeching tool was leaving, my choice.

Result: All air-driven tools have been banished for exterior use only.
 
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Noise

Neglected to mention that the aforementioned HF tool is also a bit loud (cheap gears). I do wear ear plugs when using it, but not when using conventional straight drill for sanding. Have some hearing loss, so trying to save what is left.
 
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