Grinding Aluminum: Can anyone five me advice on how to go about grinding and finishing a piece of aluminum? I had some cutting done on it and it is very jagged and I want to knock down...

Spiritof27 Loc: Lincoln, CA

Can anyone five me advice on how to go about grinding and finishing a piece of aluminum? I had some cutting done on it and it is very jagged and I want to knock down the sharp edges and smooth it down. I don't care what it looks like at all - just don't want it to cut me or scratch me when I handle it. I take a blood thinner every day and so that's one thing - bleed - that can do extremely well. I have a 4.5 inch angle grinder but the discs I have are just loading up with aluminum. Any suggestions on what type of disc to get?

Robert J Samples Loc: Round Rock, Texas

Spirit: Have you a handy pair of leather gloves? That would be my first step. Next, for the really rough edges I would start with a file if you have one, it is slow but sure. Once that was about all you can do, then perhaps a trip to the hardwarestore for new disc for the grinder. Just Sayin...RJS

Jeremy Loc: America

Your NOT supposed to grind soft metals on a grinding (abrasive wheel) wheel because the wheel gets plugged up and may explode later. Can you use a file? Course Sand paper on an electric sander. belt sander with course belts? I googled it. Guy suggests a die grinder with grinding grease it white. Good Luck Spirit. Be Careful if you take warafin or other blood thinners.

Salmoneater22 Loc: I live in S.E. Washington state.

I agree a file and card will take it down. As long as your not taking off more than you can chew.

Jefcon Loc: Washington state

First lesson I learned in Airframe & Powerplant school in sheet metal class was "... break all sharp edges". On 2024 aluminum, the usual aircraft grade AL, use a mill bastard file. And you don't have to take a lot. And don't forget to clean it every so often with a file card.

Spiritof27 Loc: Lincoln, CA

Oh I've got way way more than I could ever chew. It's a pretty big piece of aluminum with a lot of jagged edges. How does one go about preventing a file from loading up with aluminum? I do have a file, but I don't want to have to spend hours on this damn thing. RJ I do have several pairs of leather gloves and I've got the proper eye protection.

I have no idea what a die grinder is and I'm trying to save money by doing this myself. I could not find a machine shop that was willing to mill this thing to my specs - that would have been ideal.

A card? What's a "card"?

And if I'm going to get a new disc, what kind of disc should I get to do this job? T27? Flap? I know just about enough to be dangerous.

Smokypig Loc: Cheyenne, wyoming

In the category of not really any of my business, what aluminum product are you grinding. If it part of a boat bottom, o airplane wing, you should be very careful.

plumbob Loc: New Windsor Maryland

Jeremy wrote:

Your NOT supposed to grind soft metals on a grinding (abrasive wheel) wheel because the wheel gets plugged up and may explode later. Can you use a file? Course Sand paper on an electric sander. belt sander with course belts? I googled it. Guy suggests a die grinder with grinding grease it white. Good Luck Spirit. Be Careful if you take warafin or other blood thinners.

I agree with the young Jeremy. He isn't as bad as you guys said he was.

Between a file and 80 grit sand paper on a bench belt sander was my go to back in the day.

Jefcon Loc: Washington state

a file card is a small hand-held tool of about 1/4 inch thick wood, one side of which has a synthetic bristle brush and on the other is a brush made of short wire strands. When the file gets "loaded" with aluminum shavings, one uses the wire bristle side to clean the file and then finishes it off with the synthetic bristle side. You can find them at the hardware store. I use mine all the time.

DeeJay Loc: Southwest Virginia

4 1/2 " grinder with a sanding disc (layered sandpaper). If the disc clogs tun it over a piece of metal for a few seconds, it will clear it out. You can sand it to a shiny finish, no burrs. It will work, I have did that several times. DEEJAY

Robert J Samples Loc: Round Rock, Texas

Spirit: Some good advice floating around. I suspect you undertook a big job without much, or enough planning. Are we dealing with sheet aluminum or a solid block? I think Jefcon has offered a simple solution to your file(s) loading up. But, is that enough. It depends a lot on just how much more shaping, or cutting you are going to have to do. In any case, pace yourself, and be careful. Just Sayin...RJS

Video Bob Loc: Norfolk, Va

Spirit,
Worked in metal fabrication for many years. 1st regardless of what grit you use your not going to eliminate the aluminum clogging up your disc. Depending on the size & thickness of the piece your working with I recommend you NOT use a disc grinder or sander. If the piece your working on is flexible you take a chance of of it slicing into the disc causing possible injury to you or your hands. The best way to clean up/smooth the edges of what ever your working on is to clamp it to a 1x 8 - 10 or 12 leaving the edge of aluminum hanging over approx a inch. You then have 2 options. One is using a 1 inch steel hand file to clean up the jagged edges or a "flat board" with 80 grit. If you want a nice clean smooth edge just keep reducing the grit size until you get what you want.

Salmoneater22 Loc: I live in S.E. Washington state.

Good call VIDBOB

Spiritof27 Loc: Lincoln, CA

Jefcon wrote:

a file card is a small hand-held tool of about 1/4 inch thick wood, one side of which has a synthetic bristle brush and on the other is a brush made of short wire strands. When the file gets "loaded" with aluminum shavings, one uses the wire bristle side to clean the file and then finishes it off with the synthetic bristle side. You can find them at the hardware store. I use mine all the time.

Thank you jefcon - I will look for one. 80 grit on a flap disc? I can certainly do that.

I bought a 3' by 3" by 1/2" aluminum bar of aluminum and I'm using for the transom for a motor mount I'm building for my kayak. I don't really need all that aluminum, I just basically need the 3' by 3" frame and a couple of places for a couple of screws. So I took it to a shop and had them remove all the metal I don't need. I did this to reduce weight, as even though it is aluminum it is a very solid hunk of metal. The result will serve my purpose, but like I said it is very rough and jagged. So I don't care what it looks like when it's finished - the fish aren't going to care, but I don't want it to make me bleed when I handle it.

Barnacles Loc: Northern California

There's a type of file that's better for soft metals, it's called a vixen file. It has teeth that curve from one edge of the file to the other, and with a little space in between them. They can loaf up too, but not nearly as much as a regular file. Google vixen file.
Also - I think I remember a shop teacher telling us that if you wet the file with a little kerosene, it won't load up quite as bad.