Pneumatic DA Sanders

[Never Enough Money]

I got one as a birthday gift, a Porter-Cable.

Seems my 3 gallon compressor ain't enough to keep it humming. I have to stop frequently to let the pressure rebuild. Just how a big a compressor is apprpriate?

[Knothead]

Minimal 120 gallon 2 stage and that will likely run constantly trying to keep up

[noOne]

Now I think they have a name for that type of gift. Let me think. Oh yeah, I think that's called a White Elephant:-b

[Jim Wilson]

It's all about CFM. And duty cycle. Check the manual or www.porter- cable.com for specs on your model, but continuous service for pneumatic DA ROS's typically consumes 15CFM at 90psi.

My compressor sustains perhaps 11CFM at 90psi. It runs a Dynabrade ROS slightly underpowered, but adequately for most work. If I have more than a half hour of continuous sanding to do, I lower the regulator pressure to 80 psi and set up an external fan to help cool the compressor. Under those conditions, the compressor is on about 80% of the time. Not ideal, but it does get the job done.

Jim

[Mike Marlow]

For most DA's you'll need at least 12SCFM.

[Mike Marlow]

Not at all. I have a single stage with two massive cylinders and a 60 gal tank and it cycles in an acceptable manner running my DA. It's all about air volume. Mine delivers 18.7 SCFM at 100lbs and 16 SCFM at 145lbs. Plenty for a DA.

[Never Enough Money]

Holy moly!

[Robert Galloway]

Eh? I have four cylinders, single stage, three HP. Not three HP "developed" or whatever the advertising hype says but 3 HP on the motor nameplate. Keeps up with sanders and everything I've tried except a big sandblast gun. Tank is 20 gal. I takes it a long time to shut off again but it gets there eventually, (running the sander).

bob g.

Never Enough M> I got one as a birthday gift, a Porter-Cable.

[Robert Galloway]

Just out of curiosity, "How many legit HP does your compressor have powering it?". I don't remember how many SCFM my two pumps are rated at. I have two, two cylinder pumps (single stage) on a 3HP motor, 20 gal tank. Runs and ROS OK, cycles, smells a little warm after an hour or so but doesn't get too hot to touch except the heads and air line to the tank.

bob g.

Mike Marlow wrote:

[Mike Marlow]

Don't know for sure what the real HP is since I've never measured the current flow. It's rated at 7HP max, so you can guess at what the real HP is.

-Mike-

[Greg O]

Porter Cable advertises 15 CFM needed to run their pneumatic DA sanders. That said I run a DA sander off my Porter Cable air compressor often. This model.

almost keeps up! It runs steady when the sander is running, and the pressure in the tank may drop to 80 PSI but no lower. Most of the time when sanding you do not run steady for more than a few minutes so it gives the compressor a chance to catch up. If you are serious about sanding you will need a bigger unit, perhaps an honest 5 HP. Perhaps this one, but be prepared to spend close to $1000!!

[Larry Jaques]

On Tue, 23 Nov 2004 19:21:09 GMT, "Mike Marlow" calmly ranted:

Y'know, if you guys would plane and scrape your wood, you wouldn't need so many sanders, and those you used would do the job on a much smaller air supply.

--- Is it time for your medication or mine?

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[Mike Marlow]

Are you running your DA in dual action mode Greg? I had a smaller compressor that would half operate a DA but it never delivered the air volume to properly rotate the thing. It would sand - sorta, but not really. Not compared to what a DA should do. Hook it up to a decent air delivery and it's a whole different story.

[Mike Marlow]

This is very true, but I do a lot of body work also and do you have any idea how hard it is to run a Stanley #4 over a fender? Makes you and expert at Scary Sharp technique...

[Never Enough Money]

[snip]

Hmm. I use hand planes and then sometimes touch up with a fine grit sanding (say 400). Also use sanding between finish coats. I assumed hand planes wouldn't be good for a shellac surface...

[Greg O]

Yup! Works fine. Greg