Loading ...
Sorry, an error occurred while loading the content.

RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and the occasional piece of magnesium

Expand Messages
  • Feiertag, Frederick J
    ... From: paul_probus [mailto:paul_probus@yahoo.com] Sent: Wednesday, May 01, 2002 12:41 PM To: hobbicast@yahoogroups.com Subject: [hobbicast] Re: Risks vs.
    Message 1 of 16 , May 1, 2002
    • 0 Attachment
      -----Original Message-----
      From: paul_probus [mailto:paul_probus@...]
      Sent: Wednesday, May 01, 2002 12:41 PM
      To: hobbicast@yahoogroups.com
      Subject: [hobbicast] Re: Risks vs. hazards, was Melting scrap and the
      occasional piece of magnesium
      Paul,

      Only a little agitated. I know that beginners ask lots of questions and I
      am really pleased that I can even help sometimes. My response to this
      issue was mostly editorial. I am wistful that so many young people do not
      have the chance to experience things in a context from which they can weigh
      the hazards and risks. Your message expressed the fear of having a
      magnesium fire that " could burn down their foundries at best or kill them
      at worst. " This is just the sort of statement that worries me. The hazard
      of having 20 or 100 lbs of propane released and igniting is far more of a
      risk to be managed than a small quantity magnesium fire in a multi-walled
      refractory vessel,(crucible furnace).

      I'll go back into my thaumaturgist's lair and wait for a chance to pounce on
      metallurgical confusion. I'll leave the field of social engineering to
      others for now.

      Sorry if I have carelessly bothered anyone. I do mean it when I say:

      Be careful and have fun!

      Fred Feiertag




      --- In hobbicast@y..., "Feiertag, Frederick J"
      <frederick.j.feiertag@b...> wrote:
      > I have been biting my tongue so to speak, but it is time to
      contribute to
      > this discussion.
      <snip an excellent response to hazards in melting metal>

      Fred,

      You have given an excellent response to the magnesium burning
      question and since you are an experienced metalcaster, I know that
      you are telling us the truth. However, I, too, had concerns if I
      were to mistakenly melt magnesium thinking its aluminum and I believe
      that that concern was a valid one. I take it by the tone of your
      response (and I could be reading into it wrong) that you were a bit
      agitated and I'm sure this question has already been asked here.
      However, please don't get agitated with us newbies to metalcasting
      for having concerns such as this. Afterall, most people do realize
      that magnesium burns so hot that putting out a magnesium fire is hard
      and it could burn down their foundries at best or kill them at
      worst. Now, because of your sharing your knowledge with us, we know
      that there is a much smaller risk of starting a magnesium fire during
      an accidental melt of the material than we (newbies) worry about.

      The majority of your posts have been very helpful and full of useful
      information, please keep sharing your experiences with us. Please,
      though, have patience with us (and future) newbies, we have a lot to
      learn and you have a lot of experience we could learn from. If I am
      wrong about your being agitated, I am sorry for the misunderstanding.

      Paul

      Paul
    • Greg Boyd
      I learned just exactly what mag can do when it catches fire . I have this habit of doing destructive testing on just about anything that can be dangerous . Yes
      Message 2 of 16 , May 1, 2002
      • 0 Attachment
        I learned just exactly what mag can do when it catches fire .

        I have this habit of doing destructive testing on just about anything that
        can be dangerous . Yes , releasing 100# of propane . Now I do this in an
        area that it is safe to do this kind of stuff in .

        When I decided to cast some 50/50 Mg/Al , I wanted to know what would happen
        if a pot of mag caught fire . Well when making the melt , it caught fire in
        the pot . HMMMMM kinda neat looking . How do I put it out ..... throw in a
        couple of wood coffee stirs . No oxy , no fire .

        So now I think .... what happens if I spill when pouring ?
        I took a small amount and poured it on the ground . HMMMMM. pretty bright
        light . No big deal . I kept working my way up , until I took about a half
        gallon of molten mag and tossed the cruc across the yard . Made a whole
        bunch of little white flares . Still no big deal .

        All this may sound like a stupid dumbass thing to do . Yes it was , but it
        also allowed me to see that all of the old scare tactics were over rated .
        Yes it would start fires , but I don't cast on a wood floor in my house .
        Spill a bunch of Al on your wood floor and you get a fire , same as with mag
        .

        Life is dangerous , as with anything , experiment ( SLOWLY) and find out
        what your limits are . Common since will carry you a long way .
        Greg
        >
        > Only a little agitated. I know that beginners ask lots of questions and I
        > am really pleased that I can even help sometimes. My response to this
        > issue was mostly editorial. I am wistful that so many young people do not
        > have the chance to experience things in a context from which they can
        weigh
        > the hazards and risks. Your message expressed the fear of having a
        > magnesium fire that " could burn down their foundries at best or kill
        them
        > at worst. " This is just the sort of statement that worries me.
      • awemawson
        Speaking as someone who has had an unexpected magnesium fire perhaps I can comment: Most of my (hobby) casting has been from scrap, so rarely do I know what is
        Message 3 of 16 , May 1, 2002
        • 0 Attachment
          Speaking as someone who has had an unexpected magnesium fire perhaps
          I can comment:

          Most of my (hobby) casting has been from scrap, so rarely do I know
          what is in it, and the metal tends to be selected by coming from a
          source similar to what my casting is going to be. Much of it has
          originated over the years from scrap cast chassis of large computer
          printers (source at work!), and these obviously have been sand cast
          from the surface texture.

          Over maybe 15 years I have only had one magnesium fire. The melt went
          fine, the pour went fine, but when I put down the crucible to scrape
          out any remaining crud, off went the small ammount of Magnesium left
          in the dross at the bottom.

          Ok there were a few white fumes, so I threw some dry sand over it and
          left it to burn out. No great panic. Now I suspect that the metal I
          was pouring had a significant percentage of Mg, but only caught
          alight when there was a high level of oxygen (ie me stirring arround
          cleaning up)

          I don't want to play down the seriousness of a full crucible of Mg
          popping off - that would be very nasty - but I suspect the risk of it
          happening is very small unless you're melting light aircraft!

          Oh how I wish I had a magic machine that would analyise my big pile
          of unknown light alloy ingots!

          Andrew Mawson
          Bromley,Kent, UK
        • Hal J. Schechner
          Fred, You ve explained away most of the fears of a complete meltdown due to getting some mag into a propane fired furnace. It was a great explanation, and I
          Message 4 of 16 , May 2, 2002
          • 0 Attachment
            Fred,

            You've explained away most of the fears of a complete
            meltdown due to getting some mag into a propane fired furnace.
            It was a great explanation, and I for one appreciate it. On
            the other hand, I use an electric furnace. Unlike propane, I'm
            not consuming all available O2, so I'm still a bit concerned.

            I've been very careful to not put any mag into my crucible (I
            use mostly pistonium, so it's really not a big problem) but I
            was wondering how much of a risk mag is in an electric furnace.

            The chamber is rather small (9"x9"x6") and the exhaust vent is
            maybe .5". I'd guess that while I'm not burning all available
            O2, I'm also not injecting air into the furnace so there wouldn't
            be enough O2 to sustain any large burn. Opinions? Of course, I'm
            not going to become more careless just because you say "dont worry",
            but it'll put my mind at ease a bit ;)

            -Hal


            ---------------------------------------------------------
            Hal Schechner
            hal-j@...
            http://www.palmstation.com
            _The_ place for up to date Palm/Pilot info
            ---------------------------------------------------------

            On Wed, 1 May 2002, Feiertag, Frederick J wrote:

            >
            >
            > -----Original Message-----
            > From: paul_probus [mailto:paul_probus@...]
            > Sent: Wednesday, May 01, 2002 12:41 PM
            > To: hobbicast@yahoogroups.com
            > Subject: [hobbicast] Re: Risks vs. hazards, was Melting scrap and the
            > occasional piece of magnesium
            > Paul,
            >
            > Only a little agitated. I know that beginners ask lots of questions and I
            > am really pleased that I can even help sometimes. My response to this
            > issue was mostly editorial. I am wistful that so many young people do not
            > have the chance to experience things in a context from which they can weigh
            > the hazards and risks. Your message expressed the fear of having a
            > magnesium fire that " could burn down their foundries at best or kill them
            > at worst. " This is just the sort of statement that worries me. The hazard
            > of having 20 or 100 lbs of propane released and igniting is far more of a
            > risk to be managed than a small quantity magnesium fire in a multi-walled
            > refractory vessel,(crucible furnace).
            >
            > I'll go back into my thaumaturgist's lair and wait for a chance to pounce on
            > metallurgical confusion. I'll leave the field of social engineering to
            > others for now.
            >
            > Sorry if I have carelessly bothered anyone. I do mean it when I say:
            >
            > Be careful and have fun!
            >
            > Fred Feiertag
            >
            >
            >
            >
            > --- In hobbicast@y..., "Feiertag, Frederick J"
            > <frederick.j.feiertag@b...> wrote:
            > > I have been biting my tongue so to speak, but it is time to
            > contribute to
            > > this discussion.
            > <snip an excellent response to hazards in melting metal>
            >
            > Fred,
            >
            > You have given an excellent response to the magnesium burning
            > question and since you are an experienced metalcaster, I know that
            > you are telling us the truth. However, I, too, had concerns if I
            > were to mistakenly melt magnesium thinking its aluminum and I believe
            > that that concern was a valid one. I take it by the tone of your
            > response (and I could be reading into it wrong) that you were a bit
            > agitated and I'm sure this question has already been asked here.
            > However, please don't get agitated with us newbies to metalcasting
            > for having concerns such as this. Afterall, most people do realize
            > that magnesium burns so hot that putting out a magnesium fire is hard
            > and it could burn down their foundries at best or kill them at
            > worst. Now, because of your sharing your knowledge with us, we know
            > that there is a much smaller risk of starting a magnesium fire during
            > an accidental melt of the material than we (newbies) worry about.
            >
            > The majority of your posts have been very helpful and full of useful
            > information, please keep sharing your experiences with us. Please,
            > though, have patience with us (and future) newbies, we have a lot to
            > learn and you have a lot of experience we could learn from. If I am
            > wrong about your being agitated, I am sorry for the misunderstanding.
            >
            > Paul
            >
            > Paul
            >
            > Please visit our sponsor: Budget Casting Supply
            > http://budgetcastingsupply.com/
            >
            > Files area and list services are at:
            > http://groups.yahoo.com/group/hobbicast
            >
            > To unsubscribe from this group, send an email to:
            > hobbicast-unsubscribe@egroups.com
            >
            >
            >
            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            >
            >
          • Feiertag, Frederick J
            Hal, I wondered if any electric melters would ask... I still think you have little to worry about. Inside that nice quiet little furnace there is next to no
            Message 5 of 16 , May 2, 2002
            • 0 Attachment
              Hal,

              I wondered if any electric melters would ask...

              I still think you have little to worry about. Inside that nice quiet little
              furnace there is next to no free oxygen. Why is that? The aluminum melt
              has fully consumed it creating dross. Now if your furnace has a big hole in
              the bottom and top and you leave them open, you can create a good draft that
              would support a fire. But, it would be hard to melt much with the barn door
              open.

              Burning magnesium is just like burning any other fuel. Imagine instead if
              you asked me what would happen if a lump of charcoal were to be accidentally
              charged into the melt. Would it burn up the furnace and so on? Of course
              your experience can help you understand that charcoal burns quietly and
              slowly. One lump doesn't contain enough fuel to burn much of anything.

              The same almost applies to magnesium. If you charged a piece into your
              melt, and there were enough air currents to support combustion, you would
              get a small quiet fire that just happens to be very very bright. It could
              at worst mess up your melt and your crucible. But, I sincerely think that
              is unlikely.

              If you ever have the chance, visit a foundry that melts and pours magnesium.
              The melting furnaces are typically gas fired with welded steel pots that are
              lifted out for pouring. Yes, they do use cover gas or flux to reduce
              burning. That is as much to reduce metal waste as to prevent fires.

              So when should you worry? Well if you got really careless and melted a
              whole pot full of mag and went to pour it into a sand mold you could have
              quite a mess. However, there are a number of hidden safeguards that you
              already have going for you. First, you just might recognize that the scrap
              is lighter. Second, you would find it harder to melt, mag alloys melt a bit
              higher than aluminum. Third, the dross would be very different, (white and
              fluffy). Fourth, there might be some brilliant white spots of burning
              around the top of the melt. Fifth, when you pull the crucible for pouring,
              there would likely be some of that burning. And fifth, when you poured the
              metal into the mold there would be burning that you could not ignore. The
              melt would burn inside the mold and would produce clouds of white smoke.
              The molding sand would be ruined and possibly your flask. If you poured
              more than a couple pounds of metal you could burn through the mold and make
              a mess on the floor. The only thing that makes me a bit frightened by this
              picture is if the careless founder were to panic and try to put out the fire
              with water. Don't do that and the story will have a happy ending. "The
              shop was cleaned up and they lived happily ever after......"

              Fred Feiertag
              Boeing Materials Technology



              -----Original Message-----
              From: Hal J. Schechner [mailto:hal-j@...]
              Sent: Thursday, May 02, 2002 6:25 AM
              To: 'hobbicast@yahoogroups.com'
              Subject: RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
              the occasional piece of magnesium


              Fred,

              You've explained away most of the fears of a complete
              meltdown due to getting some mag into a propane fired furnace.
              It was a great explanation, and I for one appreciate it. On
              the other hand, I use an electric furnace. Unlike propane, I'm
              not consuming all available O2, so I'm still a bit concerned.

              I've been very careful to not put any mag into my crucible (I
              use mostly pistonium, so it's really not a big problem) but I
              was wondering how much of a risk mag is in an electric furnace.

              The chamber is rather small (9"x9"x6") and the exhaust vent is
              maybe .5". I'd guess that while I'm not burning all available
              O2, I'm also not injecting air into the furnace so there wouldn't
              be enough O2 to sustain any large burn. Opinions? Of course, I'm
              not going to become more careless just because you say "dont worry",
              but it'll put my mind at ease a bit ;)

              -Hal
            • Col. Zach Northway
              Being new to this... Just one question??? Why not h2o to put out the fire of mag. I know this is going to be a DUH kind of question and all. Is it be cause
              Message 6 of 16 , May 2, 2002
              • 0 Attachment
                Being new to this...
                Just one question???

                Why not h2o to put out the fire of mag. I know this is going to be a
                DUH kind of question and all. Is it be cause of oxygen in the water?

                Thanks,
                Col. Zach Northway








                Feiertag, Frederick J wrote:
                > Hal,
                >
                > I wondered if any electric melters would ask...
                >
                > I still think you have little to worry about. Inside that nice quiet little
                > furnace there is next to no free oxygen. Why is that? The aluminum melt
                > has fully consumed it creating dross. Now if your furnace has a big hole in
                > the bottom and top and you leave them open, you can create a good draft that
                > would support a fire. But, it would be hard to melt much with the barn door
                > open.
                >
                > Burning magnesium is just like burning any other fuel. Imagine instead if
                > you asked me what would happen if a lump of charcoal were to be accidentally
                > charged into the melt. Would it burn up the furnace and so on? Of course
                > your experience can help you understand that charcoal burns quietly and
                > slowly. One lump doesn't contain enough fuel to burn much of anything.
                >
                > The same almost applies to magnesium. If you charged a piece into your
                > melt, and there were enough air currents to support combustion, you would
                > get a small quiet fire that just happens to be very very bright. It could
                > at worst mess up your melt and your crucible. But, I sincerely think that
                > is unlikely.
                >
                > If you ever have the chance, visit a foundry that melts and pours magnesium.
                > The melting furnaces are typically gas fired with welded steel pots that are
                > lifted out for pouring. Yes, they do use cover gas or flux to reduce
                > burning. That is as much to reduce metal waste as to prevent fires.
                >
                > So when should you worry? Well if you got really careless and melted a
                > whole pot full of mag and went to pour it into a sand mold you could have
                > quite a mess. However, there are a number of hidden safeguards that you
                > already have going for you. First, you just might recognize that the scrap
                > is lighter. Second, you would find it harder to melt, mag alloys melt a bit
                > higher than aluminum. Third, the dross would be very different, (white and
                > fluffy). Fourth, there might be some brilliant white spots of burning
                > around the top of the melt. Fifth, when you pull the crucible for pouring,
                > there would likely be some of that burning. And fifth, when you poured the
                > metal into the mold there would be burning that you could not ignore. The
                > melt would burn inside the mold and would produce clouds of white smoke.
                > The molding sand would be ruined and possibly your flask. If you poured
                > more than a couple pounds of metal you could burn through the mold and make
                > a mess on the floor. The only thing that makes me a bit frightened by this
                > picture is if the careless founder were to panic and try to put out the fire
                > with water. Don't do that and the story will have a happy ending. "The
                > shop was cleaned up and they lived happily ever after......"
                >
                > Fred Feiertag
                > Boeing Materials Technology
                >
                >
                >
                > -----Original Message-----
                > From: Hal J. Schechner [mailto:hal-j@...]
                > Sent: Thursday, May 02, 2002 6:25 AM
                > To: 'hobbicast@yahoogroups.com'
                > Subject: RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                > the occasional piece of magnesium
                >
                >
                > Fred,
                >
                > You've explained away most of the fears of a complete
                > meltdown due to getting some mag into a propane fired furnace.
                > It was a great explanation, and I for one appreciate it. On
                > the other hand, I use an electric furnace. Unlike propane, I'm
                > not consuming all available O2, so I'm still a bit concerned.
                >
                > I've been very careful to not put any mag into my crucible (I
                > use mostly pistonium, so it's really not a big problem) but I
                > was wondering how much of a risk mag is in an electric furnace.
                >
                > The chamber is rather small (9"x9"x6") and the exhaust vent is
                > maybe .5". I'd guess that while I'm not burning all available
                > O2, I'm also not injecting air into the furnace so there wouldn't
                > be enough O2 to sustain any large burn. Opinions? Of course, I'm
                > not going to become more careless just because you say "dont worry",
                > but it'll put my mind at ease a bit ;)
                >
                > -Hal
                >
                > Please visit our sponsor: Budget Casting Supply
                > http://budgetcastingsupply.com/
                >
                > Files area and list services are at:
                > http://groups.yahoo.com/group/hobbicast
                >
                > To unsubscribe from this group, send an email to:
                > hobbicast-unsubscribe@egroups.com
                >
                >
                >
                > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                >
                >
                >
                >
                >
              • Feiertag, Frederick J
                Not a duh question. One aspect of burning light metals, like magnesium, is their extremely high combustion temperature. This is another way of talking
                Message 7 of 16 , May 2, 2002
                • 0 Attachment
                  Not a "duh" question. One aspect of burning light metals, like magnesium,
                  is their extremely high combustion temperature. This is another way of
                  talking about how reactive they are. So your guess is basically correct.
                  When molten, (and/or burning), magnesium contacts water the magnesium tears
                  apart the water molecule to get the oxygen. So putting out a mag fire with
                  water does not work. The preferred method is to smother the fire to starve
                  it of oxygen. A good way to do this is to shovel on powdered talc. Now you
                  know what to do with the rest of that five gallon bucket of parting powder!

                  Fred Feiertag
                  Boeing Materials Technology Single Aisle Platform Support
                  425-237-8255


                  -----Original Message-----
                  From: Col. Zach Northway [mailto:swapmeet@...]
                  Sent: Thursday, May 02, 2002 7:51 AM
                  To: hobbicast@yahoogroups.com
                  Subject: Re: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                  the occasional piece of magnesium


                  Being new to this...
                  Just one question???

                  Why not h2o to put out the fire of mag. I know this is going to be a
                  DUH kind of question and all. Is it be cause of oxygen in the water?

                  Thanks,
                  Col. Zach Northway








                  Feiertag, Frederick J wrote:
                  > Hal,
                  >
                  > I wondered if any electric melters would ask...
                  >
                  > I still think you have little to worry about. Inside that nice quiet
                  little
                  > furnace there is next to no free oxygen. Why is that? The aluminum melt
                  > has fully consumed it creating dross. Now if your furnace has a big hole
                  in
                  > the bottom and top and you leave them open, you can create a good draft
                  that
                  > would support a fire. But, it would be hard to melt much with the barn
                  door
                  > open.
                  >
                  > Burning magnesium is just like burning any other fuel. Imagine instead if
                  > you asked me what would happen if a lump of charcoal were to be
                  accidentally
                  > charged into the melt. Would it burn up the furnace and so on? Of course
                  > your experience can help you understand that charcoal burns quietly and
                  > slowly. One lump doesn't contain enough fuel to burn much of anything.
                  >
                  > The same almost applies to magnesium. If you charged a piece into your
                  > melt, and there were enough air currents to support combustion, you would
                  > get a small quiet fire that just happens to be very very bright. It could
                  > at worst mess up your melt and your crucible. But, I sincerely think that
                  > is unlikely.
                  >
                  > If you ever have the chance, visit a foundry that melts and pours
                  magnesium.
                  > The melting furnaces are typically gas fired with welded steel pots that
                  are
                  > lifted out for pouring. Yes, they do use cover gas or flux to reduce
                  > burning. That is as much to reduce metal waste as to prevent fires.
                  >
                  > So when should you worry? Well if you got really careless and melted a
                  > whole pot full of mag and went to pour it into a sand mold you could have
                  > quite a mess. However, there are a number of hidden safeguards that you
                  > already have going for you. First, you just might recognize that the
                  scrap
                  > is lighter. Second, you would find it harder to melt, mag alloys melt a
                  bit
                  > higher than aluminum. Third, the dross would be very different, (white
                  and
                  > fluffy). Fourth, there might be some brilliant white spots of burning
                  > around the top of the melt. Fifth, when you pull the crucible for
                  pouring,
                  > there would likely be some of that burning. And fifth, when you poured
                  the
                  > metal into the mold there would be burning that you could not ignore. The
                  > melt would burn inside the mold and would produce clouds of white smoke.
                  > The molding sand would be ruined and possibly your flask. If you poured
                  > more than a couple pounds of metal you could burn through the mold and
                  make
                  > a mess on the floor. The only thing that makes me a bit frightened by
                  this
                  > picture is if the careless founder were to panic and try to put out the
                  fire
                  > with water. Don't do that and the story will have a happy ending. "The
                  > shop was cleaned up and they lived happily ever after......"
                  >
                  > Fred Feiertag
                  > Boeing Materials Technology
                  >
                  >
                  >
                  > -----Original Message-----
                  > From: Hal J. Schechner [mailto:hal-j@...]
                  > Sent: Thursday, May 02, 2002 6:25 AM
                  > To: 'hobbicast@yahoogroups.com'
                  > Subject: RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                  > the occasional piece of magnesium
                  >
                  >
                • kirkbecnel@comcast.net
                  water and molten metal do not mix. Water is a definite no no in the casting area. Once I poured molten lead into a wet mold and a volcano erupted sort of. I
                  Message 8 of 16 , May 2, 2002
                  • 0 Attachment
                    water and molten metal do not mix. Water is a definite no no in the casting
                    area. Once I poured molten lead into a wet mold and a volcano erupted sort
                    of. I suspect other metals to have similar behaviours. White hot metal
                    spewing everywhere is not fun.

                    ----- Original Message -----
                    From: "Col. Zach Northway" <swapmeet@...>
                    To: <hobbicast@yahoogroups.com>
                    Sent: Thursday, May 02, 2002 9:51 AM
                    Subject: Re: [hobbicast] Re: Risks vs. hazards, was Melting scrap and the
                    occasional piece of magnesium


                    > Being new to this...
                    > Just one question???
                    >
                    > Why not h2o to put out the fire of mag. I know this is going to be a
                    > DUH kind of question and all. Is it be cause of oxygen in the water?
                    >
                    > Thanks,
                    > Col. Zach Northway
                    >
                    >
                    >
                    >
                    >
                    >
                    >
                    >
                    > Feiertag, Frederick J wrote:
                    > > Hal,
                    > >
                    > > I wondered if any electric melters would ask...
                    > >
                    > > I still think you have little to worry about. Inside that nice quiet
                    little
                    > > furnace there is next to no free oxygen. Why is that? The aluminum
                    melt
                    > > has fully consumed it creating dross. Now if your furnace has a big
                    hole in
                    > > the bottom and top and you leave them open, you can create a good draft
                    that
                    > > would support a fire. But, it would be hard to melt much with the barn
                    door
                    > > open.
                    > >
                    > > Burning magnesium is just like burning any other fuel. Imagine instead
                    if
                    > > you asked me what would happen if a lump of charcoal were to be
                    accidentally
                    > > charged into the melt. Would it burn up the furnace and so on? Of
                    course
                    > > your experience can help you understand that charcoal burns quietly and
                    > > slowly. One lump doesn't contain enough fuel to burn much of anything.
                    > >
                    > > The same almost applies to magnesium. If you charged a piece into your
                    > > melt, and there were enough air currents to support combustion, you
                    would
                    > > get a small quiet fire that just happens to be very very bright. It
                    could
                    > > at worst mess up your melt and your crucible. But, I sincerely think
                    that
                    > > is unlikely.
                    > >
                    > > If you ever have the chance, visit a foundry that melts and pours
                    magnesium.
                    > > The melting furnaces are typically gas fired with welded steel pots that
                    are
                    > > lifted out for pouring. Yes, they do use cover gas or flux to reduce
                    > > burning. That is as much to reduce metal waste as to prevent fires.
                    > >
                    > > So when should you worry? Well if you got really careless and melted a
                    > > whole pot full of mag and went to pour it into a sand mold you could
                    have
                    > > quite a mess. However, there are a number of hidden safeguards that you
                    > > already have going for you. First, you just might recognize that the
                    scrap
                    > > is lighter. Second, you would find it harder to melt, mag alloys melt a
                    bit
                    > > higher than aluminum. Third, the dross would be very different, (white
                    and
                    > > fluffy). Fourth, there might be some brilliant white spots of burning
                    > > around the top of the melt. Fifth, when you pull the crucible for
                    pouring,
                    > > there would likely be some of that burning. And fifth, when you poured
                    the
                    > > metal into the mold there would be burning that you could not ignore.
                    The
                    > > melt would burn inside the mold and would produce clouds of white smoke.
                    > > The molding sand would be ruined and possibly your flask. If you poured
                    > > more than a couple pounds of metal you could burn through the mold and
                    make
                    > > a mess on the floor. The only thing that makes me a bit frightened by
                    this
                    > > picture is if the careless founder were to panic and try to put out the
                    fire
                    > > with water. Don't do that and the story will have a happy ending. "The
                    > > shop was cleaned up and they lived happily ever after......"
                    > >
                    > > Fred Feiertag
                    > > Boeing Materials Technology
                    > >
                    > >
                    > >
                    > > -----Original Message-----
                    > > From: Hal J. Schechner [mailto:hal-j@...]
                    > > Sent: Thursday, May 02, 2002 6:25 AM
                    > > To: 'hobbicast@yahoogroups.com'
                    > > Subject: RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                    > > the occasional piece of magnesium
                    > >
                    > >
                    > > Fred,
                    > >
                    > > You've explained away most of the fears of a complete
                    > > meltdown due to getting some mag into a propane fired furnace.
                    > > It was a great explanation, and I for one appreciate it. On
                    > > the other hand, I use an electric furnace. Unlike propane, I'm
                    > > not consuming all available O2, so I'm still a bit concerned.
                    > >
                    > > I've been very careful to not put any mag into my crucible (I
                    > > use mostly pistonium, so it's really not a big problem) but I
                    > > was wondering how much of a risk mag is in an electric furnace.
                    > >
                    > > The chamber is rather small (9"x9"x6") and the exhaust vent is
                    > > maybe .5". I'd guess that while I'm not burning all available
                    > > O2, I'm also not injecting air into the furnace so there wouldn't
                    > > be enough O2 to sustain any large burn. Opinions? Of course, I'm
                    > > not going to become more careless just because you say "dont worry",
                    > > but it'll put my mind at ease a bit ;)
                    > >
                    > > -Hal
                    > >
                    > > Please visit our sponsor: Budget Casting Supply
                    > > http://budgetcastingsupply.com/
                    > >
                    > > Files area and list services are at:
                    > > http://groups.yahoo.com/group/hobbicast
                    > >
                    > > To unsubscribe from this group, send an email to:
                    > > hobbicast-unsubscribe@egroups.com
                    > >
                    > >
                    > >
                    > > Your use of Yahoo! Groups is subject to
                    http://docs.yahoo.com/info/terms/
                    > >
                    > >
                    > >
                    > >
                    > >
                    >
                    >
                    >
                    >
                    > Please visit our sponsor: Budget Casting Supply
                    > http://budgetcastingsupply.com/
                    >
                    > Files area and list services are at:
                    > http://groups.yahoo.com/group/hobbicast
                    >
                    > To unsubscribe from this group, send an email to:
                    > hobbicast-unsubscribe@egroups.com
                    >
                    >
                    >
                    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                    >
                    >
                  • Col. Zach Northway
                    Great I understand now. But one more question as always... Someone said you can check to see if your metal is mag with vinager. Anyone know how todo this?
                    Message 9 of 16 , May 2, 2002
                    • 0 Attachment
                      Great I understand now.

                      But one more question as always...

                      Someone said you can check to see if your metal is mag with vinager.
                      Anyone know how todo this? Thanks,
                      Col. Zach Northway










                      Feiertag, Frederick J wrote:
                      > Not a "duh" question. One aspect of burning light metals, like magnesium,
                      > is their extremely high combustion temperature. This is another way of
                      > talking about how reactive they are. So your guess is basically correct.
                      > When molten, (and/or burning), magnesium contacts water the magnesium tears
                      > apart the water molecule to get the oxygen. So putting out a mag fire with
                      > water does not work. The preferred method is to smother the fire to starve
                      > it of oxygen. A good way to do this is to shovel on powdered talc. Now you
                      > know what to do with the rest of that five gallon bucket of parting powder!
                      >
                      > Fred Feiertag
                      > Boeing Materials Technology Single Aisle Platform Support
                      > 425-237-8255
                      >
                      >
                      > -----Original Message-----
                      > From: Col. Zach Northway [mailto:swapmeet@...]
                      > Sent: Thursday, May 02, 2002 7:51 AM
                      > To: hobbicast@yahoogroups.com
                      > Subject: Re: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                      > the occasional piece of magnesium
                      >
                      >
                      > Being new to this...
                      > Just one question???
                      >
                      > Why not h2o to put out the fire of mag. I know this is going to be a
                      > DUH kind of question and all. Is it be cause of oxygen in the water?
                      >
                      > Thanks,
                      > Col. Zach Northway
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      > Feiertag, Frederick J wrote:
                      >
                      >>Hal,
                      >>
                      >>I wondered if any electric melters would ask...
                      >>
                      >>I still think you have little to worry about. Inside that nice quiet
                      >
                      > little
                      >
                      >>furnace there is next to no free oxygen. Why is that? The aluminum melt
                      >>has fully consumed it creating dross. Now if your furnace has a big hole
                      >
                      > in
                      >
                      >>the bottom and top and you leave them open, you can create a good draft
                      >
                      > that
                      >
                      >>would support a fire. But, it would be hard to melt much with the barn
                      >
                      > door
                      >
                      >>open.
                      >>
                      >>Burning magnesium is just like burning any other fuel. Imagine instead if
                      >>you asked me what would happen if a lump of charcoal were to be
                      >
                      > accidentally
                      >
                      >>charged into the melt. Would it burn up the furnace and so on? Of course
                      >>your experience can help you understand that charcoal burns quietly and
                      >>slowly. One lump doesn't contain enough fuel to burn much of anything.
                      >>
                      >>The same almost applies to magnesium. If you charged a piece into your
                      >>melt, and there were enough air currents to support combustion, you would
                      >>get a small quiet fire that just happens to be very very bright. It could
                      >>at worst mess up your melt and your crucible. But, I sincerely think that
                      >>is unlikely.
                      >>
                      >>If you ever have the chance, visit a foundry that melts and pours
                      >
                      > magnesium.
                      >
                      >>The melting furnaces are typically gas fired with welded steel pots that
                      >
                      > are
                      >
                      >>lifted out for pouring. Yes, they do use cover gas or flux to reduce
                      >>burning. That is as much to reduce metal waste as to prevent fires.
                      >>
                      >>So when should you worry? Well if you got really careless and melted a
                      >>whole pot full of mag and went to pour it into a sand mold you could have
                      >>quite a mess. However, there are a number of hidden safeguards that you
                      >>already have going for you. First, you just might recognize that the
                      >
                      > scrap
                      >
                      >>is lighter. Second, you would find it harder to melt, mag alloys melt a
                      >
                      > bit
                      >
                      >>higher than aluminum. Third, the dross would be very different, (white
                      >
                      > and
                      >
                      >>fluffy). Fourth, there might be some brilliant white spots of burning
                      >>around the top of the melt. Fifth, when you pull the crucible for
                      >
                      > pouring,
                      >
                      >>there would likely be some of that burning. And fifth, when you poured
                      >
                      > the
                      >
                      >>metal into the mold there would be burning that you could not ignore. The
                      >>melt would burn inside the mold and would produce clouds of white smoke.
                      >>The molding sand would be ruined and possibly your flask. If you poured
                      >>more than a couple pounds of metal you could burn through the mold and
                      >
                      > make
                      >
                      >>a mess on the floor. The only thing that makes me a bit frightened by
                      >
                      > this
                      >
                      >>picture is if the careless founder were to panic and try to put out the
                      >
                      > fire
                      >
                      >>with water. Don't do that and the story will have a happy ending. "The
                      >>shop was cleaned up and they lived happily ever after......"
                      >>
                      >>Fred Feiertag
                      >>Boeing Materials Technology
                      >>
                      >>
                      >>
                      >>-----Original Message-----
                      >>From: Hal J. Schechner [mailto:hal-j@...]
                      >>Sent: Thursday, May 02, 2002 6:25 AM
                      >>To: 'hobbicast@yahoogroups.com'
                      >>Subject: RE: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                      >>the occasional piece of magnesium
                      >>
                      >>
                      >
                      >
                      > Please visit our sponsor: Budget Casting Supply
                      > http://budgetcastingsupply.com/
                      >
                      > Files area and list services are at:
                      > http://groups.yahoo.com/group/hobbicast
                      >
                      > To unsubscribe from this group, send an email to:
                      > hobbicast-unsubscribe@egroups.com
                      >
                      >
                      >
                      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                      >
                      >
                      >
                      >
                      >
                    • paul_probus
                      Fred, I didn t want you to take my reply as a flame and I am sorry if you did. I was merely trying to point out that we newbies need someone with your
                      Message 10 of 16 , May 2, 2002
                      • 0 Attachment
                        Fred,

                        I didn't want you to take my reply as a flame and I am sorry if you
                        did. I was merely trying to point out that we newbies need someone
                        with your experience and knowledge to take a breath and let the
                        agitation with our questions subside a little and give us the benefit
                        of your experience. I do not mean for you to "shut up, sit down and
                        wait to be called on", I want you to continue to jump in and correct
                        our mis-information. I have learned a lot from you and have saved
                        many of your messages with useful information, I don't want you to
                        stop, like someone else mentioned, I would like to see you write a
                        book to share with us what you know.

                        I have read your other responses to the magnesium issue and I now
                        feel better that melting magnesium by mistake will probably not end
                        up "... burn(ing) down their foundries at best or kill them at
                        worst." When I wrote that statement in my original post, I did not
                        mean that statement as a fact or something I experienced. It was
                        meant to be taken as what I fear could happen, as someone who has a
                        little knowledge of magnesium but no experience attempting to melt
                        it. As I said at the beginning of this paragraph, now I know, from
                        your other posts, that this is unlikely and I thank you for sharing
                        what happens if someone were to melt a crucible full of magnesium.
                        You can be sure I have saved that article as well.

                        Paul

                        --- In hobbicast@y..., "Feiertag, Frederick J"
                        <frederick.j.feiertag@b...> wrote:
                        >
                        >
                        > -----Original Message-----
                        > From: paul_probus [mailto:paul_probus@y...]
                        > Sent: Wednesday, May 01, 2002 12:41 PM
                        > To: hobbicast@y...
                        > Subject: [hobbicast] Re: Risks vs. hazards, was Melting scrap and
                        the
                        > occasional piece of magnesium
                        > Paul,
                        >
                        > Only a little agitated. I know that beginners ask lots of
                        questions and I
                        > am really pleased that I can even help sometimes. My response to
                        this
                        > issue was mostly editorial. I am wistful that so many young people
                        do not
                        > have the chance to experience things in a context from which they
                        can weigh
                        > the hazards and risks. Your message expressed the fear of having a
                        > magnesium fire that " could burn down their foundries at best or
                        kill them
                        > at worst. " This is just the sort of statement that worries me.
                        The hazard
                        > of having 20 or 100 lbs of propane released and igniting is far
                        more of a
                        > risk to be managed than a small quantity magnesium fire in a multi-
                        walled
                        > refractory vessel,(crucible furnace).
                        >
                        > I'll go back into my thaumaturgist's lair and wait for a chance to
                        pounce on
                        > metallurgical confusion. I'll leave the field of social
                        engineering to
                        > others for now.
                        >
                        > Sorry if I have carelessly bothered anyone. I do mean it when I
                        say:
                        >
                        > Be careful and have fun!
                        >
                        > Fred Feiertag
                        >
                        >
                        >
                        >
                        > --- In hobbicast@y..., "Feiertag, Frederick J"
                        > <frederick.j.feiertag@b...> wrote:
                        > > I have been biting my tongue so to speak, but it is time to
                        > contribute to
                        > > this discussion.
                        > <snip an excellent response to hazards in melting metal>
                        >
                        > Fred,
                        >
                        > You have given an excellent response to the magnesium burning
                        > question and since you are an experienced metalcaster, I know that
                        > you are telling us the truth. However, I, too, had concerns if I
                        > were to mistakenly melt magnesium thinking its aluminum and I
                        believe
                        > that that concern was a valid one. I take it by the tone of your
                        > response (and I could be reading into it wrong) that you were a bit
                        > agitated and I'm sure this question has already been asked here.
                        > However, please don't get agitated with us newbies to metalcasting
                        > for having concerns such as this. Afterall, most people do realize
                        > that magnesium burns so hot that putting out a magnesium fire is
                        hard
                        > and it could burn down their foundries at best or kill them at
                        > worst. Now, because of your sharing your knowledge with us, we
                        know
                        > that there is a much smaller risk of starting a magnesium fire
                        during
                        > an accidental melt of the material than we (newbies) worry about.
                        >
                        > The majority of your posts have been very helpful and full of
                        useful
                        > information, please keep sharing your experiences with us. Please,
                        > though, have patience with us (and future) newbies, we have a lot
                        to
                        > learn and you have a lot of experience we could learn from. If I
                        am
                        > wrong about your being agitated, I am sorry for the
                        misunderstanding.
                        >
                        > Paul
                        >
                        > Paul
                      • Feiertag, Frederick J
                        Paul, Don t worry. As most hobbicast fellows seem to have thick skins, I ll stick around. My skin might not be as thick as some, but my head sure is.... I m
                        Message 11 of 16 , May 2, 2002
                        • 0 Attachment
                          Paul,

                          Don't worry. As most hobbicast fellows seem to have thick skins, I'll stick
                          around. My skin might not be as thick as some, but my head sure is.... I'm
                          glad that everyone here wants to contribute what they can; questions,
                          answers, opinions, and even worries. For awhile I'll try not to stomp too
                          hard on the worries!

                          I do like this group, even when the threads stray from perfect civility,
                          they seem to find their was back quickly. Nice.

                          Fred F.



                          -----Original Message-----
                          From: paul_probus [mailto:paul_probus@...]
                          Sent: Thursday, May 02, 2002 10:03 AM
                          To: hobbicast@yahoogroups.com
                          Subject: [hobbicast] Re: Risks vs. hazards, was Melting scrap and the
                          occasional piece of magnesium


                          Fred,

                          I didn't want you to take my reply as a flame and I am sorry if you
                          did. I was merely trying to point out that we newbies need someone
                          with your experience and knowledge to take a breath and let the
                          agitation with our questions subside a little and give us the benefit
                          of your experience. I do not mean for you to "shut up, sit down and
                          wait to be called on", I want you to continue to jump in and correct
                          our mis-information. I have learned a lot from you and have saved
                          many of your messages with useful information, I don't want you to
                          stop, like someone else mentioned, I would like to see you write a
                          book to share with us what you know.

                          I have read your other responses to the magnesium issue and I now
                          feel better that melting magnesium by mistake will probably not end
                          up "... burn(ing) down their foundries at best or kill them at
                          worst." When I wrote that statement in my original post, I did not
                          mean that statement as a fact or something I experienced. It was
                          meant to be taken as what I fear could happen, as someone who has a
                          little knowledge of magnesium but no experience attempting to melt
                          it. As I said at the beginning of this paragraph, now I know, from
                          your other posts, that this is unlikely and I thank you for sharing
                          what happens if someone were to melt a crucible full of magnesium.
                          You can be sure I have saved that article as well.

                          Paul

                          --- In hobbicast@y..., "Feiertag, Frederick J"
                          <
                        • Doug
                          I have actually tried to ignite one of those magnesium alloy mower decks with no success. First in a bonfire being used to melt down large aluminum pieces,
                          Message 12 of 16 , May 2, 2002
                          • 0 Attachment
                            I have actually tried to ignite one of those magnesium alloy mower decks
                            with no success. First in a bonfire being used to melt down large aluminum
                            pieces, then in the furnace itself, with only very small "fizzles" of the
                            white light typical of magnesium.

                            Doug Freeland
                            Brighton, MI.
                            ----- Original Message -----
                            From: "Feiertag, Frederick J" <frederick.j.feiertag@...>
                            To: <hobbicast@yahoogroups.com>
                            Sent: Wednesday, May 01, 2002 2:53 PM
                            Subject: [hobbicast] Risks vs. hazards, was Melting scrap and the occasional
                            piece of magnesium


                            > I have been biting my tongue so to speak, but it is time to contribute to
                            > this discussion.
                            >
                            > First the practical, if a bit of mag alloy found its way into your
                            crucible
                            > no real harm would happen. Your alloy would be compromised and if you are
                            > melting odd scrap it might even be improved.
                            >
                            > Could you start a fire? Yes, funny thing about that. Don't you have a
                            > "fire" burning to melt this stuff anyway? So you might have more
                            combustion
                            > that planned.... But how could this occur? In order to have significant
                            > combustion you need enough air to support the fire. If your furnace is
                            > burning properly there should be little free oxygen available to support
                            the
                            > fire. I know how vigorous mag is about getting the oxygen it needs to
                            burn.
                            > But it still needs ample contact with air to get a good start. Bulk mag
                            in
                            > a crucible does not burn well. It can be smothered with a scoop of dry
                            > sand, talc is preferred. So even if you start a small fire it can be
                            > managed with little trouble.
                            >
                            > Now on to the real issue: Hazards and Risks. This is an underlying topic
                            > for many threads for the hobbicasters. Just recently we have read
                            messages
                            > about carbon monoxide, magnesium, and the dangers of a cluttered desk!
                            All
                            > these are valid hazards. Are they significant risks? Casting molten
                            metal
                            > is a wild mixture of hazards and risks. To succeed safely we need to
                            > balance and mange both the hazards and the risks. In our modern world it
                            > seems to be "politically" correct to confuse both and treat the risks the
                            > same as the hazards. I have trouble with that.
                            >
                            > There are hazards we do nothing about, such as being hit by an asteroid,
                            or
                            > having all the oxygen in the room spontaneously move to the roof. Why
                            don't
                            > we do anything about these hazards? Because the risk of them happening in
                            > our lifetime is so vanishingly small. Major risk, minor hazard. On the
                            > other hand we wear shoes to manage the risk of stepping on something that
                            > would make us uncomfortable or injure our feet. Minor hazard, major
                            risk.
                            > Risk is the probability of trouble happening. Hazard is trouble
                            independent
                            > of odds.
                            >
                            > In the foundry we have lots of hazards, most can be managed to reduce the
                            > risk of injury without too much trouble. All I'm pleading for is to keep
                            > your eyes open to the real risks and let the long odds take a back seat.
                            >
                            > For example:
                            >
                            > Always check out your scrap. You don't want to put mag into your melt for
                            > many reasons, starting a fire should be a minor one. Combustion can
                            produce
                            > CO, but it does not have to be a serious risk. Ventilation at the very
                            > least is a good way to put the odds in your favor. The smokers reading
                            this
                            > get a bigger dose of CO each day that the rest of use do standing around a
                            > well tuned propane burner.
                            >
                            > Phew, now I feel better.
                            > Have fun, stay up wind, keep your eyes open!
                            >
                            > Fred F.
                            > Whose opinions are his own and rarely shared by his spouse.
                            >
                            >
                            >
                            >
                            > -----Original Message-----
                            > From: Col. Zach Northway [mailto:swapmeet@...]
                            > Sent: Wednesday, May 01, 2002 10:53 AM
                            > To: hobbicast@yahoogroups.com
                            > Subject: Re: [hobbicast] Melting scrap and the occassional piece of
                            > magnesium
                            >
                            >
                            > I have an engine shop that saves me engine blocks and any scrap they
                            > have laying around. So this could be a problem for me. How do you test
                            > with vinagar? Thanks,
                            > Col. Zach Northway
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            > Please visit our sponsor: Budget Casting Supply
                            > http://budgetcastingsupply.com/
                            >
                            > Files area and list services are at:
                            > http://groups.yahoo.com/group/hobbicast
                            >
                            > To unsubscribe from this group, send an email to:
                            > hobbicast-unsubscribe@egroups.com
                            >
                            >
                            >
                            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                            >
                            >
                          • Bruce Mowbray
                            ... FWIW, Those mower decks to burn, especially when you try to put out a garden shed fire with water. My father was a fireman and I used to go with him (when
                            Message 13 of 16 , May 3, 2002
                            • 0 Attachment
                              At 07:02 PM 5/2/02 -0400, you wrote:
                              > I have actually tried to ignite one of those magnesium alloy mower decks
                              >with no success. First in a bonfire being used to melt down large aluminum
                              >pieces, then in the furnace itself, with only very small "fizzles" of the
                              >white light typical of magnesium.
                              >

                              FWIW,
                              Those mower decks to burn, especially when you try to put out a garden
                              shed fire with water. My father was a fireman and I used to go with him
                              (when I was much younger) to some of the less serious fire calls. One of
                              them was a garden shed fire. The structure was fully invloved and when the
                              unsuspecting man on the nozzle hit the now red hot mower deck with a stream
                              of water, you would have thought it was the fourth of july. Bright white
                              sparks and a white cloud of smoke shot skyward. Fortunatly, he and
                              everybody else was a good distance away. Spectacular!!

                              Magnesium does burn, but only with a good supply of oxygen.




                              Bruce Mowbray
                              trainhead@...
                              http://www.geocities.com/trainhead391/
                              TMB Manufacturing and Locomotive Works
                              1 1/2" Scale & 2 1/2" Scale (Narrow Gauge) Live Steamer
                            • John
                              ... tears ... This can acutally happen at a much lower temperature than magnesium burns at. It s not really that the magnesium is heating the water to a point
                              Message 14 of 16 , May 3, 2002
                              • 0 Attachment
                                > Not a "duh" question. One aspect of burning light metals, like magnesium,
                                > is their extremely high combustion temperature. This is another way of
                                > talking about how reactive they are. So your guess is basically correct.
                                > When molten, (and/or burning), magnesium contacts water the magnesium
                                tears
                                > apart the water molecule to get the oxygen.

                                This can acutally happen at a much lower temperature than magnesium burns
                                at. It's not really that the magnesium is heating the water to a point where
                                it splits (That'd take a lot of energy for sure). If you take some hot steam
                                and pass it over very warm magnesium you get the very bright flare of
                                magnesium oxidising. If you just put very warm magnesium in hot water
                                nothing happens though.

                                The steam is hot enough that all the water is going round as gas molecules
                                and these in turn have lots of energy since the steam is very hot. When they
                                hit the warm magnesium the energy is enough that the steam oxidises the
                                magnesium. Once it starts the heat released supports any more oxidisation.
                                And yes, hydrogen is release. We do it with a little test tube and about 4cm
                                of ribbon magnesium. Enough hydrogen is released to burn at the tip of the
                                tube for about 10 seconds are so. It's very impressive!

                                We were told that occasionally titanium scrap heaps go on fire and that when
                                they do the fire brigade just watch them burn down rather than trying to put
                                it out.

                                John H.
                              Your message has been successfully submitted and would be delivered to recipients shortly.