Air compressor requirements for power sanding

I have burned up 2 cheap-o HF angle drills with power sanding and am considering going to a pneumatic sander. What capacity air compressor would I need to supply the sander for power sanding on the lathe? Any suggestions on a sander?

They usually use about 4cfm+ at 90PSI. They use quite a bit of air. Probably a 60+ gallon unit with a decent pump would work.


Alan

Eric,
I work for a large air compressor manufacturer and would venture to guess that your looking at a minimum of 5 hp ,18+ cfm and at least a 60 gallon tank. We have a great sander line from Aro and some of them require upwards of 25 cfm to be used continuosly. A lot of air sanders stae in there specifications that 3 to 8 cfm is sufficient but that is generally not in a continuos use. Really check your requirements on the sander side of the equation to save yourself alot of aggravation. Also,find a sander that runs at a slow speed or you will burn up your sandpaper.
Greg

I got this one for the same reason:
http://www.harborfreight.com/catalog...q=air%20sander
The specs say it uses 15 cfm and it certainly uses lots of air. I don't know how long it will last but it works great and is less tiring than the close quarter drills I had been using.

Thanks, guys, Great info.

Not really sure what kind of sanding you are doing but most air sanders take 15CFM or more. That's a lot of air. If you are just doing RO sanding then you could get a Mirka Ceros for a lot less than a new pneumatic sander and compressor. It has all the power of a Dynabrade and only uses 400 W of electricity, much less than a large compressor.

I would think that getting a nice quality electric angle sander would be better if you are thinking money. Maybe a Festool or a Makita or Bosch. If you have other uses for the large compressor you might just want to have it for those other reasons.

I tried a pneumatic sander, and quit using it. It requires oil, which can leak out on the bowls. There was minimal water, which also can leak out, but spotting was minimal. You can set up water traps in a line if you have one, and some times at the compressor. Main dis like was the air hose, which is way more in the way than the electrical cord, and it kept the compressor running non stop.

I did find out my drills last a lot longer if I use minimal pressure (the weight of the drill is almost too much), and slow speeds in the 300 to 600 rpm range, or the trigger pulled down less than half way. It actually seems to cut/sand better than the higher speeds, and the abrasives also last longer.

robo hippy

Hi Eric,
Good info! 60 Gallon or more, 90 PSI for a pnuematic random orbital sanders (ROS). Also random orbital sanders are good for the higher grits such as 180-220 grit and higher because of the finesse action they provide but for the lower grits I recommend something more as a drill that provides the torgue you will need to dig out the deep scratches and tool marks. ROS with a soft innerface pad, low speed and light touch work great on the higher grits. The disc is either cutting into the surface or skating over the surface because of too much speed! Generally it does a little of both! WHat I encourage is people try to feel the resistance from the abrasive to the material/wood! As you go up in grit... go down in sanding speed! When I get to 280-320 grit my lathe is spinning 50rpm! WHy go faster?!?! It is fine sanding at 320 grit!!! I have to give the abrasive a chance to cut the wood. All I am doing is what I call "clouding or fogging" the piece of wood at this point sanding 320, 400,600 etc. If your drills are burning up try to blow them out and keep them cool. Also, little to no heat when sanding on both the pads and the drill. It can be done! We forget these are drill and not sanders. They are not designed to kept wide open for extensive periods of time. I am not saying you do this but in my hundreds of conversations I can say this I something that happens alot. You have much good info here and I hope this helps. Vince

Eric, I just went through this and ended up replacing my little shop compressor, which was fine for pneumatic nailers, with an 80 gallon, 16.9 scfm @ 100 psi model. There have been several threads on high speed sanding and one by Dan Forman got me started. HF has several inexpensive angle grinders and some have air exhausts which point away from the work, thus minimizing the oil problem. There isn't that much oil involved, anyway, maybe a drop a day. HF also has a set of 2 and 3 inch sanding pads with 1/4" shafts and quick change aluminum oxide abrasives and Scotch type pads. They may not be as good as the expensive stuff, but they work well enough and fit the grinder collet.

I haven't timed it, but the grinders cycle the new compressor after about two minutes of use. The pump seems to almost keep up, but I have imagined a loss of power maybe 3 or 4 minutes into sanding, suggesting the pressure may have dropped. I haven't actually checked that, either. I have the regulator set at 90 psi.

I got some good advice on shopping for a compressor in the general woodworking forum. http://www.sawmillcreek.org/showthre...lue&highlight=

I have both and use both. However, you will save no money using air as versus electric sanders.You can burn out a lot of electric sanders for the cost of a good compressor and a selection of pneumatic sanders. My compressor is 5 hp with an 80 gallon storage tank and I run it up to 175 pounds in the tank. It runs as much as it rests running even a small bowl sander. I use good quality sanders, Chicago Pneumatic, Ingersoll and Dynabrade and they are still much louder than the electric angle drills. My compressor in in the next room with an insulated wall between and it still adds to the noise. Research carefully before jumping into a big compressor. "It can be the gift that keeps on taking."

I have a Makita angle drill that is more than 20 years old. I have dropped it on the floor at least 100 times and beat it every way possible and it just keeps on working. To me, if the a good angle drill is a better and more cost effective solution than buying a big compressor.

A compressor's output should only be expressed in"(#s air @ #psi) It is the rate that counts and not the max psi or max vol.