Aluminum vs. magnesium, science!

Discussion in 'General foundry chat' started by chris.trotter, Apr 13, 2018.

  1. chris.trotter

    chris.trotter Copper

    Thought I'd contribute, might be helpful to those in future uncertain about "what does magnesium fizzing w. vinegar look like?".

    After reading about someone who'd accidentally dropped magnesium into their aluminum melt (and then had to wait out the ensuing inferno), I immediately became suspicious about this old belt grinder I just recycled (an old Elu that I stupidly dropped, cracked the casting). When disassembling it I kinda thought the castings felt much lighter than aluminum, but it certainly looked the part, so I did some tests.
    1. Filing - aluminum feels much coarser/grabbier under the file. The magnesium was MUCH easier to file, it came off with almost no effort.
    2. Appearance of exposed metal - the aluminum was a duller silver colour, the magnesium almost looked like polished steel.
    3. Vinegar - using freshly filed flat sections, it is painfully obvious which one fizzes, like you cannot mix them up.
    Here's a pic of two freshly filed sections. Aluminum on the left, magnesium on the right.
    2018-04-12 20.33.00.jpg

    And here's a quick video:
    oldironfarmer and DavidF like this.
  2. Tobho Mott

    Tobho Mott Silver Banner Member

    Nice example, thanks.

  3. Jason

    Jason Silver Banner Member

    Good demo. Might save some clueless individual some pain. Another obvious difference, magnesium drills like butter and the chips are way different than aluminium.
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    I remember awhile back.... There was this guy who was doing some tig welding on a intake off of a lawn tractor that turned out to be magnesium.... Would have been a big help if "he" knew about this then....:rolleyes:
    Tobho Mott likes this.
  5. Jason

    Jason Silver Banner Member

    Magnesium is one of those things, you should know it when you see it if you are half paying attention. Then again, some people have a hard time identifying steel from aluminium.:rolleyes:

    I'd pay money to see some tig welder light up on a mag lawnmower part. Bet he messed his shorts! :Do_O
  6. DavidF

    DavidF Administrator Staff Member Banner Member

    Hush it!!! LOL
    Jason likes this.
  7. chris.trotter

    chris.trotter Copper

    I will see if I can get some pics of chip differences.

    @DavidF Need more detail. Did the entire thing self-combust in a glorious inferno?
  8. DavidF

    DavidF Administrator Staff Member Banner Member

    Not so much, it actually would just pop with a bright flash leaving behind a BB sized crater and white smoke trails.
  9. crazybillybob

    crazybillybob Silver Banner Member

    Wait a minute.... You mean I can't go after the mower with my mig ? :eek::oops: So far I haven't had a problem. Maybe I just buy really cheap mowers :p
  10. _Jason

    _Jason Copper

    crazybillybob and Jason like this.

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