Re: a new question: Magnesium

Discussion in 'Cycling Equipment' started by maxxevv, Jul 8, 2004.

  1. maxxevv

    maxxevv Guest

    Brad Behm wrote:
    > Hello, I posted the question below about my bent frame. Thank you
    > everyone for your excellent advice. Anyway I found what looks to be a
    > good deal on a magnesium frame. But I know nothing about magnesium
    > frames. Apparently it's a little like al. right? but lighter?
    > This is what I found: Merida magnesium 909 road frame with carbon ahead
    > fork for $250
    > Is this a pretty good deal? pros and cons of magnesium? Your opinions
    > are greatly appreciated.
    > Thanks again,
    > Andrew




    Wow ... where's that ? Anywhere online ??

    Would be interested in magnesium. Would be glad if you can post
    me a link.

    Thanks. ;)



    --
     
    Tags:


  2. TomD

    TomD Guest

    maxxevv <[email protected]> wrote in message news:<[email protected]>...
    > Brad Behm wrote:
    > > Hello, I posted the question below about my bent frame. Thank you
    > > everyone for your excellent advice. Anyway I found what looks to be a
    > > good deal on a magnesium frame. But I know nothing about magnesium
    > > frames. Apparently it's a little like al. right? but lighter?
    > > This is what I found: Merida magnesium 909 road frame with carbon ahead
    > > fork for $250
    > > Is this a pretty good deal? pros and cons of magnesium? Your opinions
    > > are greatly appreciated.
    > > Thanks again,
    > > Andrew

    >
    >
    >
    > Wow ... where's that ? Anywhere online ??
    >
    > Would be interested in magnesium. Would be glad if you can post
    > me a link.


    http://www.chucksbikes.com/
     
  3. ZeeExSixAre

    ZeeExSixAre Guest

    maxxevv wrote:
    > Brad Behm wrote:
    > > Hello, I posted the question below about my bent frame. Thank you
    > > everyone for your excellent advice. Anyway I found what looks to

    > be a > good deal on a magnesium frame. But I know nothing about
    > magnesium > frames. Apparently it's a little like al. right? but
    > lighter? > This is what I found: Merida magnesium 909 road frame
    > with carbon ahead > fork for $250
    > > Is this a pretty good deal? pros and cons of magnesium? Your

    > opinions > are greatly appreciated.
    > > Thanks again,
    > > Andrew

    >
    >
    >
    > Wow ... where's that ? Anywhere online ??
    >
    > Would be interested in magnesium. Would be glad if you can post
    > me a link.


    That would be so cool if it were actually (pure) magnesium. You could set
    one portion aflame and it would erupt in a gigantic fireworks display. You
    could then say, "I could have either ridden it or set it on fire... the fire
    was so much more fun!"

    --
    Phil, Squid-in-Training
     
  4. Prometheus

    Prometheus Guest

    --On Thursday, July 08, 2004 5:51 PM -0400 ZeeExSixAre
    <[email protected]> wrote:

    > That would be so cool if it were actually (pure) magnesium. You could set
    > one portion aflame and it would erupt in a gigantic fireworks display.
    > You could then say, "I could have either ridden it or set it on fire...
    > the fire was so much more fun!"
    >
    > --
    > Phil, Squid-in-Training


    Unfortunately for you and the other pyros, this stuff isn't pure magnesium.
    I saw some examples of what I assume is similar stuff at SAE World
    Congress, and its a magnesium/aluminum alloy, that has strength properties
    similar to magnesium but can be worked and machined like aluminum. And its
    1/3 the weight of aluminum. But, its 3 times the price (per weight, which
    isn't how you buy stock). So given those, the pricing is similar to
    aluminum as well. Looks like it might have a future in the automotive
    industry, so it may make it into mainstream bikes before too long as well.

    Mike
    Mechanical Engineering 2006, Carnegie Mellon University
    Remove nospam to reply.
     
  5. ZeeExSixAre

    ZeeExSixAre Guest

    Prometheus wrote:
    > --On Thursday, July 08, 2004 5:51 PM -0400 ZeeExSixAre
    > <[email protected]> wrote:
    >
    >> That would be so cool if it were actually (pure) magnesium. You
    >> could set one portion aflame and it would erupt in a gigantic
    >> fireworks display. You could then say, "I could have either ridden
    >> it or set it on fire... the fire was so much more fun!"
    >>
    >> --
    >> Phil, Squid-in-Training

    >
    > Unfortunately for you and the other pyros, this stuff isn't pure
    > magnesium.


    Well, of course!

    I saw some examples of what I assume is similar stuff at
    > SAE World Congress, and its a magnesium/aluminum alloy, that has
    > strength properties similar to magnesium but can be worked and
    > machined like aluminum. And its 1/3 the weight of aluminum. But


    Innnnteresting....

    > 3 times the price (per weight, which isn't how you buy stock). So
    > given those, the pricing is similar to aluminum as well. Looks like
    > it might have a future in the automotive industry, so it may make it
    > into mainstream bikes before too long as well.



    But this $240 frame can hardly be the kind of alloy you speak of. It
    probably doesn't have anything special in it other than the regular amount
    of mag that's alloyed with aluminum for 6061 and such.

    --
    Phil, Squid-in-Training
     
  6. Chalo

    Chalo Guest

    "ZeeExSixAre" <[email protected]> wrote:
    >
    > That would be so cool if it were actually (pure) magnesium. You could set
    > one portion aflame and it would erupt in a gigantic fireworks display. You
    > could then say, "I could have either ridden it or set it on fire... the fire
    > was so much more fun!"


    Pure magnesium would be useless for a bicycle frame, just like pure
    aluminum is useless for that purpose. However, there are several
    structural alloys of Mg that have been used for bike frames in the
    past, by Kirk Precision and Litech among others. Merida has been
    using magnesium alloy for some time:

    http://www.merida.com/s0_global/main_control.php?group0=tech&group1=magnesium&group2=0&

    It's only 2/3 as dense as aluminum, and similarly less stiff and less
    strong. So most of the benefits, characteristics and tradeoffs of
    aluminum frames will also be exhibited in a magnesium frame.

    I am curious as to how well magnesium copes with fatigue.

    FWIW, I have machined magnesium structural alloys before, and their
    shavings burn similarly to those of pure magnesium. It would be tough
    to spot-heat a piece as large as a bike frame enough to ignite it,
    without resorting to something like an oxyacetylene torch, though.

    Chalo Colina
     
  7. Chalo

    Chalo Guest

    "ZeeExSixAre" <[email protected]> wrote:
    >
    > That would be so cool if it were actually (pure) magnesium. You could set
    > one portion aflame and it would erupt in a gigantic fireworks display. You
    > could then say, "I could have either ridden it or set it on fire... the fire
    > was so much more fun!"


    Pure magnesium would be useless for a bicycle frame, just like pure
    aluminum is useless for that purpose. However, there are several
    structural alloys of Mg that have been used for bike frames in the
    past, by Kirk Precision and Litech among others. Merida has been
    using magnesium alloy for some time:

    http://www.merida.com/s0_global/main_control.php?group0=tech&group1=magnesium&group2=0&

    It's only 2/3 as dense as aluminum, and similarly less stiff and less
    strong. So most of the benefits, characteristics and tradeoffs of
    aluminum frames will also be exhibited in a magnesium frame.

    I am curious as to how well magnesium copes with fatigue.

    FWIW, I have machined magnesium structural alloys before, and their
    shavings burn similarly to those of pure magnesium. It would be tough
    to spot-heat a piece as large as a bike frame enough to ignite it,
    without resorting to something like an oxyacetylene torch, though.

    Chalo Colina
     
  8. bfd

    bfd Guest

    "Chalo" <[email protected]> wrote in message
    news:[email protected]
    > "ZeeExSixAre" <[email protected]> wrote:
    > >
    > > That would be so cool if it were actually (pure) magnesium. You could

    set
    > > one portion aflame and it would erupt in a gigantic fireworks display.

    You
    > > could then say, "I could have either ridden it or set it on fire... the

    fire
    > > was so much more fun!"

    >
    > Pure magnesium would be useless for a bicycle frame, just like pure
    > aluminum is useless for that purpose. However, there are several
    > structural alloys of Mg that have been used for bike frames in the
    > past, by Kirk Precision and Litech among others. Merida has been
    > using magnesium alloy for some time:
    >

    I would recommend staying far away from the Kirk Precision Mg frames. JUNK!
    You never ever see one as just about every single one broke! This may be the
    last remaining one alive:

    http://www.firstflightbikes.com/KirkPrecision.html
     
  9. bfd

    bfd Guest

    "Chalo" <[email protected]> wrote in message
    news:[email protected]
    > "ZeeExSixAre" <[email protected]> wrote:
    > >
    > > That would be so cool if it were actually (pure) magnesium. You could

    set
    > > one portion aflame and it would erupt in a gigantic fireworks display.

    You
    > > could then say, "I could have either ridden it or set it on fire... the

    fire
    > > was so much more fun!"

    >
    > Pure magnesium would be useless for a bicycle frame, just like pure
    > aluminum is useless for that purpose. However, there are several
    > structural alloys of Mg that have been used for bike frames in the
    > past, by Kirk Precision and Litech among others. Merida has been
    > using magnesium alloy for some time:
    >

    I would recommend staying far away from the Kirk Precision Mg frames. JUNK!
    You never ever see one as just about every single one broke! This may be the
    last remaining one alive:

    http://www.firstflightbikes.com/KirkPrecision.html
     
  10. Jim Smith

    Jim Smith Guest

    [email protected] (Chalo) writes:

    > FWIW, I have machined magnesium structural alloys before, and their
    > shavings burn similarly to those of pure magnesium. It would be tough
    > to spot-heat a piece as large as a bike frame enough to ignite it,
    > without resorting to something like an oxyacetylene torch, though.
    >


    I know for a fact that a medium sized camp-type fire will readily
    ignite one of those magnesium alloy engine cases from an old
    air-cooled volkswagen, with spectacular results.
     
  11. Werehatrack

    Werehatrack Guest

    On 8 Jul 2004 19:11:50 -0700, [email protected] (Chalo) wrote:

    >I am curious as to how well magnesium copes with fatigue.


    In my experience, very poorly.

    One stunning example: For their 1970 model, Volkswagen increased the
    amount of Mg in the alloy for their engine block. They'd been having
    some problems with the blocks for the 1500 and 1600 engines, and I
    heard that the expectation was that the stiffer alloy that they could
    get by going to a higher Mg content would reduce the rate of certain
    failures. They'd been having a problem with bearing saddles wallowing
    out, and with cylinder head studs shearing out threads in the block
    It turned out to be a really bad move. With the stiffer high-Mg
    alloy, the studs took longer to pull out, but the blocks were cracking
    in a dozen places where they'd never had problems before, including
    across the bearing saddles, down the back of the block at the base of
    a cylinder, etc. For 1971, they reduced the Mg content and changed a
    couple of other things, and the cracking problem vanished.

    I've heard numerous disparaging remarks about Mg as a major component
    of Mg-Al alloys from a couple of metallurgists over the years, one of
    whom was in R&D with a major fastener manufacturer for quite a while.
    He commented that it made alloys that were really nice to work with,
    but if you used too much Mg, the material got very brittle.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Surrealism is a pectinated ranzel.
     
  12. Tim Izod

    Tim Izod Guest

    Prometheus <[email protected]> wrote:
    > --On Thursday, July 08, 2004 5:51 PM -0400 ZeeExSixAre
    > <[email protected]> wrote:


    >> That would be so cool if it were actually (pure) magnesium. You could set
    >> one portion aflame and it would erupt in a gigantic fireworks display.
    >> You could then say, "I could have either ridden it or set it on fire...
    >> the fire was so much more fun!"
    >>
    >> --
    >> Phil, Squid-in-Training


    > Unfortunately for you and the other pyros, this stuff isn't pure magnesium.

    [snip]

    No, but if you put enough energy into it you can still make it
    burn. Iron dust, zinc dust, aluminium filings and even aluminium bodied
    pencil sharpeners were all found to burn with a nice bright flame in our
    undergraduate labs. Though the bright light had the downside of causing
    the imminent arrival of a grumpy lab technician telling us we were
    supposed to be doing chemistry and not playing:)

    --
    Tim.
     
  13. Chalo

    Chalo Guest

    Jim Smith <[email protected]> wrote:
    >
    > [email protected] (Chalo) writes:
    > >
    > > FWIW, I have machined magnesium structural alloys before, and their
    > > shavings burn similarly to those of pure magnesium. It would be tough
    > > to spot-heat a piece as large as a bike frame enough to ignite it,
    > > without resorting to something like an oxyacetylene torch, though.

    >
    > I know for a fact that a medium sized camp-type fire will readily
    > ignite one of those magnesium alloy engine cases from an old
    > air-cooled volkswagen, with spectacular results.


    It takes a little while to ignite, though, because the case's thermal
    conductivity requires that the whole case be brought close to the
    ignition temperature before any one part of it can reach that
    temperature. It's not something one could do to a bike frame, laptop
    computer, or crankcase with just a match or a cigarette lighter
    (though those means will ignite shavings nicely).

    Chalo Colina
     
  14. In article <[email protected]>,
    [email protected] says...

    >It takes a little while to ignite, though, because the case's thermal
    >conductivity requires that the whole case be brought close to the
    >ignition temperature before any one part of it can reach that
    >temperature. It's not something one could do to a bike frame, laptop
    >computer, or crankcase with just a match or a cigarette lighter
    >(though those means will ignite shavings nicely).


    I forget where I read the article, but I do recall reading an article about
    a journalist who wanted ignite a magnesium computer case. I think it was
    a Next computer case. He went to a lot of trouble trying to do it, and
    it was not easy to do.
    --------------
    Alex
     
  15. In article <[email protected]>,
    Alex Rodriguez <[email protected]> wrote:

    > In article <[email protected]>,
    > [email protected] says...
    >
    > >It takes a little while to ignite, though, because the case's thermal
    > >conductivity requires that the whole case be brought close to the
    > >ignition temperature before any one part of it can reach that
    > >temperature. It's not something one could do to a bike frame, laptop
    > >computer, or crankcase with just a match or a cigarette lighter
    > >(though those means will ignite shavings nicely).

    >
    > I forget where I read the article, but I do recall reading an article about
    > a journalist who wanted ignite a magnesium computer case. I think it was
    > a Next computer case. He went to a lot of trouble trying to do it, and
    > it was not easy to do.


    MacWorld or MacUser. It was for a cover shoot. They wanted to do
    something special for either the return of Steve to Apple, the purchase
    of NeXT, or the intro of the Power Mac Cube.

    The special problem they had was that the Next case had a 1' cube-shaped
    shell. It was very hard to get it up to the flashpoint of magnesium.
    They went to a...well, a fire-simulation laboratory. The eventual
    technique was probably something like a big pile of magnesium shavings
    used as kindling, or just a hellaciously hot thermal start.

    Once it got burning though, whoa!

    --
    Ryan Cousineau, [email protected] http://www.wiredcola.com
    President, Fabrizio Mazzoleni Fan Club
     
  16. On Sun, 11 Jul 2004 10:55:04 -0400, Alex Rodriguez
    <[email protected]> wrote:

    >In article <[email protected]>,
    >[email protected] says...
    >
    >>It takes a little while to ignite, though, because the case's thermal
    >>conductivity requires that the whole case be brought close to the
    >>ignition temperature before any one part of it can reach that
    >>temperature. It's not something one could do to a bike frame, laptop
    >>computer, or crankcase with just a match or a cigarette lighter
    >>(though those means will ignite shavings nicely).

    >
    >I forget where I read the article, but I do recall reading an article about
    >a journalist who wanted ignite a magnesium computer case. I think it was
    >a Next computer case. He went to a lot of trouble trying to do it, and
    >it was not easy to do.
    >--------------
    >Alex


    Dear Alex,

    Yes, the NeXT case was magnesium. That choice of material
    and the rest of its design made the case a wonderful example
    of imbecile design--your library may have "Steve Jobs & the
    NeXT Big Thing" by Randall Stoss, which has a page or two on
    all the problems with the NeXT case. It's bad enough to make
    you admire modern bicycle design.

    Carl Fogel
     
  17. In article <[email protected]>,
    [email protected] wrote:

    > On Sun, 11 Jul 2004 10:55:04 -0400, Alex Rodriguez
    > <[email protected]> wrote:


    > >I forget where I read the article, but I do recall reading an article about
    > >a journalist who wanted ignite a magnesium computer case. I think it was
    > >a Next computer case. He went to a lot of trouble trying to do it, and
    > >it was not easy to do.
    > >--------------
    > >Alex

    >
    > Dear Alex,
    >
    > Yes, the NeXT case was magnesium. That choice of material
    > and the rest of its design made the case a wonderful example
    > of imbecile design--your library may have "Steve Jobs & the
    > NeXT Big Thing" by Randall Stoss, which has a page or two on
    > all the problems with the NeXT case. It's bad enough to make
    > you admire modern bicycle design.


    Mind summarizing? Offhand, I suspect the rather odd magneto-optical
    drive and the attempt to do primary ventilation through the MO drive
    slot were the big ones. The latter solution was adequate for cooling,
    but the dust destroyed the drive.

    I had a NextStation (the NeXT slab) with associated monitor for a while,
    and it's a pretty nice design. much less aggressively weird than the
    cube, and it fit nicely under the monitor. Those 17" grayscale monitors
    were a delight to use.

    --
    Ryan Cousineau, [email protected] http://www.wiredcola.com
    President, Fabrizio Mazzoleni Fan Club
     
  18. On Sun, 11 Jul 2004 16:00:08 -0700, Ryan Cousineau
    <[email protected]> wrote:

    >In article <[email protected]>,
    > [email protected] wrote:
    >
    >> On Sun, 11 Jul 2004 10:55:04 -0400, Alex Rodriguez
    >> <[email protected]> wrote:

    >
    >> >I forget where I read the article, but I do recall reading an article about
    >> >a journalist who wanted ignite a magnesium computer case. I think it was
    >> >a Next computer case. He went to a lot of trouble trying to do it, and
    >> >it was not easy to do.
    >> >--------------
    >> >Alex

    >>
    >> Dear Alex,
    >>
    >> Yes, the NeXT case was magnesium. That choice of material
    >> and the rest of its design made the case a wonderful example
    >> of imbecile design--your library may have "Steve Jobs & the
    >> NeXT Big Thing" by Randall Stoss, which has a page or two on
    >> all the problems with the NeXT case. It's bad enough to make
    >> you admire modern bicycle design.

    >
    >Mind summarizing? Offhand, I suspect the rather odd magneto-optical
    >drive and the attempt to do primary ventilation through the MO drive
    >slot were the big ones. The latter solution was adequate for cooling,
    >but the dust destroyed the drive.
    >
    >I had a NextStation (the NeXT slab) with associated monitor for a while,
    >and it's a pretty nice design. much less aggressively weird than the
    >cube, and it fit nicely under the monitor. Those 17" grayscale monitors
    >were a delight to use.


    Dear Ryan,

    While the library closes here early on Sunday, I can recall
    these problems among others with the magnesium NeXT case.
    The case fiasco was driven purely by cosmetics and serves as
    an example of the sort of things that kept going wrong when
    Steve Jobs controlled things.

    Jobs insisted on a special magnesium case, even though this
    metal has no engineering advantage over plain sheet steel
    for making computer cases.

    Magnesium just sounds cool.

    Jobs also insisted that the needlessly magnesium case had to
    be a true cube with 90-degree angles everywhere. Normally,
    casting moulds have a slight and invisible-to-the-eye taper
    of about half a degree, just as cake moulds have a much
    larger taper to help the baked cake drop out. If you want
    no-taper square moulds, they have to come apart in several
    expensive directions.

    But a perfect cube sounds cool.

    Achieving the invisible perfect 90-degree angles required
    not only special casting moulds but also touch-up work on
    the finished cases that cost the already dead-in-the-water
    NeXT company extra millions of dollars.

    Jobs also specified a brain-dead flat black paint job.

    But "black" sounds cool.

    But flat black paint is idiotic because it highlights even
    the slightest surface blemishes, which Stoss pointed out is
    why car makers reserve the very best sheet metal panels for
    the cars that they plan to paint black. With its cool flat
    black paint job, the NeXT computer often arrived showing
    scuff-marks from normal styrofoam shipping inserts, which
    cost NeXT even more money that it couldn't afford.

    While Jobs was busy with pointless materials, invisible
    angles, and bad paint choices, the rest of the project fell
    apart.

    Carl Fogel
     
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