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I'm working on a project that uses rolled aluminum, the kind for repairing chimney flashing, eavestroughs, etc. It's 0.0125" thick and has very sharp edges, especially after making sized cuts from the roll.

I've read in a few places that certain grinding/sanding accessories aren't a good idea for aluminum as it can clog the abrasive. I have a basic Dremel 100 which has a single speed of 35,000 rpm. I just got a bunch of accessories in a new kit but don't have access to it or the list of items in it at the moment.

Can anyone tell me which Dremel accessory by number would work best to remove the sharp edges from the aluminum sheet, and for cutting it as well? If the rpm is too high, what other tools or methods are recommended? I have been using a utility knife to make my cuts so far, easy but tough to be accurate.

  • Have you tried other tools (for example aviation/tin snips)? These wouldn't solve the sharpness issue, but you shouldn't have any trouble cutting the sheet with it (I've cut ~2mm aluminium sheet with snips without any issues). – walrus Oct 23 '17 at 9:56
  • Other than the rough cuts made with a utility knife, I only tried a pair of wire cutters as that's all I had on-hand. I found it deformed the aluminum a lot more than doing straight cuts with the utility knife. – dugost Oct 23 '17 at 14:55
  • Yeah, you have to be careful with them and use something to keep the sheet from deforming too much. The heavy duty scissors that fred_dot_u recommends are much the same thing. – walrus Oct 24 '17 at 8:50
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    Turns out a pair of scissors was all I needed. I was worried it would ruin them so I used an old pair and no problem because the sheet is so thin. Made for cutting curves a lot easier than a utility knife. Didn't deform the metal either. Then I used a sanding bit on my Dremel to deburr the edges. Not smooth by any means but no jagged bits and it took off the sharp edge. – dugost Oct 24 '17 at 13:53
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For material that thin, even a set of heavy duty scissors will work well enough. Harbor Freight sells stainless steel multipurpose scissors for six bucks US that should do well enough for 0.0125" stock.

HF scissors

For the sharp edges, especially in aluminum, a deburring tool should do well for your purposes. A quality tool will be somewhat expensive, but there's such a large price range in this item that you should be able to find something in your budget.

deburring tool

I have a tool similar to that in the photo and use it frequently on aluminum and plastic sheets to chamfer the edges. In your case, such thin material will need support. It may be necessary to place the edge on a solid surface such as a countertop or sharp edged table to provide the necessary support. Deburr one edge, flip the piece over and deburr the other side.

In the above photo, it appears that the E200 bit would give the best results. Light pressure, drag the cutter along the edge and you would see a curl of aluminum from the cutter. Too much pressure and you'll create a new sharp edge.

Alternative solution involves a hand file and the aforementioned support table or countertop. Push the file downward over the material creating the chamfer as you progress along the length. Dremel-type rotary tools also have burr bits that would work, but with a single speed (high speed) tool such as yours, the possibility of removing too much material is quite high.

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  • Thanks. I think my dad has pair of those scissors so I can give that a try. For the edge, I actually came across a video showing one of the deburring tools you mentioned. As the sheet is so thin, I think you're right about trying a hand file. I'll also do some tests with a Dremel bit on a piece of scrap. From what I could see in other videos, aluminum oxide and silicon carbide grinder bits don't work well as they get gummed up. One of the sandpaper bits may do the trick. (youtu.be/IBiAsSGjNMQ?t=6m21s / youtube.com/watch?v=ZA3HDDOOY9A&hd=1) – dugost Oct 23 '17 at 15:03
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    Burr bits for the Dremel class of tools are cylinders and cones and spheres constructed of cutting edges, not abrasives. They may get gummed up a bit, but not usually. It's the equivalent of a fast rotating file. They cut like crazy especially at high speed and may be challenging to handle. If you have a full Dremel kit, you may have a few included. If you get clogging on that type of bit with aluminum, a bit of kerosene or WD-40 applied periodically will prevent that. I use kerosene on my mini-mill when machining aluminum with great results. – fred_dot_u Oct 23 '17 at 15:14
  • Great tips, thanks. I think I do have some bits like that but I'll have to check later this evening. If I do, I'll be doing tests on scrap first. A comment I came across while looking into this also mentioned using 3-in-1 oil to prevent the clogging. – dugost Oct 23 '17 at 15:17
  • A copper or brass hammer can work in a pinch, easy to accidentally mar the surface however. If it is a small area you can just use a fine file. – John Oct 27 '17 at 22:17

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