Sandpaper for Polishing Aluminum

Discussion in 'Workshop Tips and Secrets / Tools' started by Marc W, Jan 27, 2018.

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  1. Jan 27, 2018 #1

    Marc W

    Marc W

    Marc W

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    This may be old news but I found an alternative to sandpaper to polish out scratches and corrosion on aluminum. Regular wet and dry paper breaks down quickly and just doesn't last very long. I have some mesh or screen paper that is sold to sand drywall with. This stuff is great! It lasts a long time and cuts well. The fine grade is 220 grit so it is a little on the coarse side for fine finishing. Once it breaks down a little it leaves a finish that is fine enough to polish with scotch brite pads. The product I have is Norton Wallsand. I haven't looked but there might be finer grit mesh sandpapers available if you want a finer finish.
     
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  2. Jan 28, 2018 #2

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    Cloth backed sand paper from industrial distributors doesn't break down like the cheap stuff. Easily found online. Klingspore and Norton are brands I buy and use.
     
  3. Jan 28, 2018 #3

    Dan Thomas

    Dan Thomas

    Dan Thomas

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    A couple of things regarding sanding aluminum:

    2024-T3 has a really thin layer of pure aluminum rolled onto each side of the sheet. This amounts to between 2% and 5% of the total sheet thickness, so it's really thin. It's there to protect the copper-alloyed aluminum from the atmosphere and moisture; the copper makes aluminum corrode in short order. Pure aluminum will oxidize almost instantly, and that oxide layer is nearly inert and will stop or slow further corrosion. Sanding, even with scotchbrite, can eat through that thin layer quickly and expose that corrosion-prone alloy to all sorts of grief.

    Some cloth-backed waterproof stuff is emery cloth. It has iron oxide as part of its makeup, and that iron will embed in the aluminum and cause monstrous and rapid corrosion. The right stuff is nothing but silicon carbide or aluminum oxide.
     
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  4. Jan 29, 2018 #4

    Marc W

    Marc W

    Marc W

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    What I speak of is not a cloth backed sandpaper. It is a mesh or screen. In fact it looks like window screen.

    I am using 6061-T6 so I don't have to worry about sanding the alclad off.
     
  5. Jan 30, 2018 #5

    Marc W

    Marc W

    Marc W

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    The abrasive in the Norton Wallsand that I have is silicon carbide. Hard stuff, it cuts well and lasts.
     

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