Pneumatic sander for fab work?

[Ingram306]

Anyone running a 5/6” pneumatic sander for doing steel fab work ? Just some small shop projects, nothing structural or anything but Ive always used an angle grinder with a flap disc to finish everything before paint. I tried a milwaukee electric random orbit palm sander and wasn’t really impressed with it.

Just wondering if a pneumatic sander would do that much better of a job and/or if anyone had any recommendations.

Thanks in advance

 

[tarbellb]

They are great for high detail fabrication work. knocking off rust, final blend for paint, breaking edges, etc...
Pneumatic Sanders will go all day, stay cool, and quality brands don't vibrate.

Look at 3M or Dynabrade, you can find deals.

 

[The Cobbler]

I've got a 6" pneumatic sander but in my opinion they're not great at removing metal. they are good on paint, wood, bondo etc.
lately I've been using sanding discs with a backer pad on angle grinders for finishing and I seem to like the results better than with flap wheels

 

[dnschmidt]

Point 1) You need a big compressor to power an air sander (5hp 80 gallon is what I use) they consume 17 SCFM and you're not getting that out of a Harbor Freight compressor.
Point 2) I like AirVantage sanders although Dynabrade Supreme are fine. Dynabrade's Spirit line *****. 3M's air sanders with the red trim are in fact made by AirVantage.
Point 3) These are not made for removing metal but for giving it a nice surface finish. For that they're excellent. For steel I typically use P80 grit and for aluminum P120 grit. You can go finer if you want shinny.

 

[tarbellb]

Agree with both posts above, Cobbler is spot on with removal expectations

If I only had one option it would be a variable speed grinder w backing pad and 40-220 grits replaceable pads

A random orbital sander is for high detail minimal removal scenarios (stroke length can make big difference, but still applies)

 

[nadogail]

High powered pneumatic tools consume a lot of compressed air. My garage shop is not equipped to handle one efficiently.

I have enough air compressor to paint a small job, like a bicycle; if I need to paint a fence, both my compressors are needed to be running.

 

[Ingram306]

I have a 60 gallon Quincy 5hp, so I’ll be a little short on CFM (I think I’m at 15.4) but I’m just looking for something to clean things up a little better than the flap disc prior to my professional rattle can job .

Thanks for all the suggestions, im going to give the fiber disc/ backing pad for the angle grinder first and see how that goes

 

[The Cobbler]

for that I would try a spot putty or a few coats if high build primer

 

[Jswain]

Fibre disc on an angle grinder is amazing IMO. If you are grinding welds etc 36 grit will hold up MUCH longer and work faster until you get it relatively smooth then step it up for a nice smooth finish.

If I have a lot of welds to grind smooth I start with a regular grinding disc to get it close then finish off with a resin fibre & the results are seamless, fast, & cheap

 

[scooby074]

Pneumatic sanders arent really the answer for moving metal.

You need to change abrasive systems. for your grinder. Things have come a long way from the old school "stone" grinding wheels.

First thing Id try is going to flap wheels. I like walter (and 3m), but there are other brands. They blend more than grind. Go with a higher grit than your typical 40, Walter has up to 120 in their flappers. With the right discs you can get a mirror polish (or a grain effect , or several other textures)

 

[tarbellb]

Pneumatic sanders arent really the answer for moving metal.

You need to change abrasive systems. for your grinder. Things have come a long way from the old school "stone" grinding wheels.

First thing Id try is going to flap wheels. I like walter (and 3m), but there are other brands. They blend more than grind. Go with a higher grit than your typical 40, Walter has up to 120 in their flappers. With the right discs you can get a mirror polish (or a grain effect , or several other textures)

Scooby do yourself a favor and try the fibre resin pad/backer combo.

much cheaper and better overall performance.

flappers have their place, but it's usually in the drawers

 

[scooby074]

Scooby do yourself a favor and try the fibre resin pad/backer combo.

much cheaper and better overall performance.

flappers have their place, but it's usually in the drawers

Absolutely! I was just thinking about the OP and getting him into something better relatively cheap (HF has flap discs under $5). Big problem with the quality discs are minimum order quantities and local availability. Cheaper on a per disc basis, but not overall when you have to buy a sleeve of 25. Discs can also warp with humidity and turn into a potato chip which is a PITA. Ive used backer pads and discs on my Bluepoint autobody pneumatic grinder/sander for years.

On the topic, I just got a new backer pad and a sleeve of 3M's Cubitron II 982cx discs to run on my electric RA grinders and so far they are kick ***. 2x as aggressive as flappers or the Sait discs I used before. Super impressive. Im going to post a followup when I get some time with them.

 

[tarbellb]

Nice

and yeah 3M abrasives are wildly effective even compared to other quality brands