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Re: Thermite was Re: [multimachine] Smelting Technologies

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  • Benjamin Bof
    Friend ; take care with amount of mix. Small quantities using electric arc to fire it adding other amounts after. Mix can blast. Magnesium is other option.
    Message 1 of 9 , May 3, 2009
      Friend ; take care with amount of mix.
      Small quantities using electric arc to fire it adding other amounts after.
      Mix can blast.
      Magnesium is other option.
      Regards, Ben

      On Sun, May 3, 2009 at 4:50 PM, Chris M <chrism3667@...> wrote:


      can anyone provide a primer on thermite? ---

      --- On Sat, 5/2/09, Keith Mc <acti@...> wrote:

      From: Keith Mc <acti@...>
      Subject: [multimachine] Smelting Technologies
      To: multimachine@yahoogroups.com
      Date: Saturday, May 2, 2009, 9:38 PM

      (Moved from thread  "Re: HAPPY WORKERS DAY FOR ALL"...
      Folks, let's please keep the Subject lines relevant to the discussion!  Thanks!)

      Besides forced aspirated burning and electric arcs, you can also use
      Thermite or other exothermic chemistry to initially heat your crucible of raw iron..

      If you do decide to use carbon in the mix and force an arc though it to heat from
      within, remember you also have the Bessemer Process, invented in the 1850s,
      that can then post process the melt to reduce the remaining carbon content.
      (See: http://en.wikipedia.org/wiki/Bessemer_process )

      Simply put, it's a lined vessel that receives a molten metal charge, which is then
      aspirated with oxygen.  This "consumes" the impurities by either converting them to
      a gas (which escapes), or collects them into a solid slag which can be separated out.

      (Avoid spambots: if quoting me, PLEASE don't quote my entire email address. Thanks!)

      - Keith Mc.


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    • Pierre Coueffin
      Finely ground aluminum mixed about 50-50 with finely ground rust. When ignited (as I recall you need a Magnesium strip to light the stuff), the aluminum will
      Message 2 of 9 , May 3, 2009
        Finely ground aluminum mixed about 50-50 with finely ground rust.
        When ignited (as I recall you need a Magnesium strip to light the
        stuff), the aluminum will burn, stripping oxygen off the rust to form
        aluminum oxide and iron. The process is very, very exothermic (that's
        actually an understatement...) So the iron comes out molten. If you
        put the thermite on top of a ceramic form and light it up, under the
        right circumstances the melted iron fills the form and when everything
        cools down, you break off the ceramic and have an iron casting. Once
        you start it, you stand well back and wait for it to burn out. You
        have little hope of putting it out before it finishes and are more
        likely to spread the very hot fire and melted metal around if you try
        to do something foolish like spraying water on it. They used to weld
        railroad tracks together this way at one point in some areas.

        There is also a commercial product called a CadWeld (made by Erico
        Products Inc of Cleveland Ohio) that uses a similar reaction (Cupric
        Oxide and Aluminum) to make melted copper. You can put a cadweld mold
        over the head of a grounding stake, put a bunch of heavy copper wires
        into the grooves in the top, load a charge of the compound and light
        it up.... When it cools down, you basically have a big block of copper
        with all the wires welded to the head of the stake. I have one of
        these left from a few a friend gave to me... They're impressive.

        I could probably scan and post the instructions that come with the
        CadWeld if you are looking for more information, they outline the
        process pretty well. Thermite would be much the same except that
        you'd have to prepare your own molds and mix your own chemicals. Very
        finely powdered aluminum dust (it will hang in the air for several
        minutes if shaken...) can be obtained from a paint supplier, they mix
        it with paint to make metallic colours for cars. Be careful not to
        breathe the stuff though, it will do bad things to your lungs. Rust
        can be made electrolytically and ground in a ball mill to the desired
        consistency. Safety precautions are a must with this stuff.

        On Sun, May 3, 2009 at 12:50 PM, Chris M <chrism3667@...> wrote:
        >
        >
        > can anyone provide a primer on thermite? ---
      • Benjamin Bof
        [edit ] The Aston process In 1925, James Aston
        Message 3 of 9 , May 3, 2009

          [edit] The Aston process

          In 1925, James Aston of the United States developed a process for manufacturing wrought iron quickly and economically. It involves taking molten steel from a Bessemer converter and pouring it into cooler liquid slag. The temperature of the steel is about 1500 °C and the liquid slag is maintained at approximately 1200 °C. The molten steel contains a large amount of dissolved gases so when the liquid steel hits the cooler surfaces of the liquid slag the gases are liberated. The molten steel then freezes to yield a spongy mass having a temperature of about 1370 °C.[21] This spongy mass must then be finished by being shingled and rolled as described under puddling (above). Three to four tons can be converted per batch with this method.[21]

          Wrought iron is no longer commercially produced. The last wrought iron facility shut down in 1969.[1] In the 1960s the price of steel production was dropping due to recycling and even using the Aston process wrought iron production was a labor intensive process. It has been estimated that the production of wrought iron costs approximately twice as much as the production of low carbon steel.[1]

          [edit] Properties

          The microstructure of wrought iron, showing dark slag inclusions in ferrite (iron)

          The slag inclusions in wrought iron give it properties not found in other forms of ferrous metal. There are approximately 250,000 inclusions per square inch.[1] A fresh fracture shows a clear bluish color with a high silky luster and fibrous appearance.

          Wrought iron lacks the carbon content necessary for hardening through heat treatment, but in areas where steel was uncommon or unknown, tools were sometimes cold-worked (hence cold iron) in order to harden them. An advantage of its low carbon content is its excellent weldability.[1] Furthermore, sheet wrought iron cannot bend as much as steel sheet metal (when cold worked).[29][30][31] Wrought iron can be cast, however there is no engineering advantage as compared to cast iron; cast iron is much easier to produce and thus cheaper, so it is exclusively chosen over wrought iron.[32][33]

          Due to the variations in iron ore origin and iron manufacture, wrought iron can be inferior or superior in corrosion resistance compared to other iron alloys.[34][1][35][36] There are many mechanisms behind this corrosion resistance. Chilton and Evans found that nickel enrichment bands reduce corrosion.[37] They also found that in puddled and forged and piled the working over of the iron spread out copper, nickel and tin impurities, which produce electrochemical conditions that slow down corrosion.[35] The slag inclusions have been shown to disperse corrosion in to an even film to resist pitting.[1] Another study has shown that slag inclusions are pathways to corrosion.[38] Other studies show that sulfur impurities in the wrought iron decrease corrosion resistance,[36] but phosphorus increase corrosion resistance.[39] Environments with a high concentration of chlorine ions also decreases wrought iron's corrosion resistance.[36]

          Wrought iron has a rough surface so it can hold platings and coatings better. For instance, a galvanic zinc finish is approximately 25–40% thicker than the same finish on steel.[1]

          In Table 1, the chemical composition of wrought iron is compared to that of pig iron and carbon steel. Although it appears that wrought iron and plain carbon steel have similar chemical compositions, this is deceiving. Most of the manganese, sulfur, phosphorus, and silicon are incorporated into the slag fibers present in the wrought iron, so wrought iron really is purer than plain carbon steel.[25]

          Table 1: Chemical composition comparison of pig iron, plain carbon steel, and wrought iron
          [25]
          MaterialIronCarbonManganeseSulfurPhosphorusSilicon
          Pig iron91–943.5–4.50.5–2.50.018–0.10.03–0.10.25–3.5
          Carbon steel98.1–99.50.07–1.30.3–1.00.02–0.060.002–0.10.005–0.5
          Wrought iron99–99.80.05–0.250.01–0.10.02–0.10.05–0.20.02–0.2
          All units are percent weight
          Table 2: Properties of wrought iron
          PropertyValue
          Ultimate tensile strength [psi (MPa)][40]34,000–54,000 (234–372)
          Ultimate compression strength [psi (MPa)][40]34,000–54,000 (234–372)
          Ultimate shear strength [psi (MPa)][40]28,000–45,000 (193–310)
          Yield point [psi (MPa)][40]23,000–32,000 (159–221)
          Modulus of elasticity (in tension) [psi (MPa)][40]28,000,000 (193,100)
          Melting point [°F (°C)][41]2,800 (1,540)
          Specific gravity7.6–7.9[42]
          7.5–7.8[43]

          Amongst its other properties, wrought iron becomes soft at red heat, and can be easily forged and forge welded.[44] It can be used to form temporary magnets, but cannot be magnetized permanently,[45][46] and is ductile, malleable and tough.[25]



          On Sun, May 3, 2009 at 4:50 PM, Chris M <chrism3667@...> wrote:


          can anyone provide a primer on thermite? ---

          --- On Sat, 5/2/09, Keith Mc <acti@...> wrote:

          From: Keith Mc <acti@...>
          Subject: [multimachine] Smelting Technologies
          To: multimachine@yahoogroups.com
          Date: Saturday, May 2, 2009, 9:38 PM

          (Moved from thread  "Re: HAPPY WORKERS DAY FOR ALL"...
          Folks, let's please keep the Subject lines relevant to the discussion!  Thanks!)

          Besides forced aspirated burning and electric arcs, you can also use
          Thermite or other exothermic chemistry to initially heat your crucible of raw iron..

          If you do decide to use carbon in the mix and force an arc though it to heat from
          within, remember you also have the Bessemer Process, invented in the 1850s,
          that can then post process the melt to reduce the remaining carbon content.
          (See: http://en.wikipedia.org/wiki/Bessemer_process )

          Simply put, it's a lined vessel that receives a molten metal charge, which is then
          aspirated with oxygen.  This "consumes" the impurities by either converting them to
          a gas (which escapes), or collects them into a solid slag which can be separated out.

          (Avoid spambots: if quoting me, PLEASE don't quote my entire email address. Thanks!)

          - Keith Mc.


          ------------------------------------

          Yahoo! Groups Links

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              (Yahoo! ID required)

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        • Benjamin Bof
          Pierre; in case of iron oxide is 70/30 percent of aluminium powder. Regards, Ben
          Message 4 of 9 , May 3, 2009
            Pierre; in case of iron oxide is 70/30 percent of aluminium powder.
            Regards, Ben

            On Sun, May 3, 2009 at 5:18 PM, Pierre Coueffin <pcoueffin@...> wrote:


            Finely ground aluminum mixed about 50-50 with finely ground rust.
            When ignited (as I recall you need a Magnesium strip to light the
            stuff), the aluminum will burn, stripping oxygen off the rust to form
            aluminum oxide and iron. The process is very, very exothermic (that's
            actually an understatement...) So the iron comes out molten. If you
            put the thermite on top of a ceramic form and light it up, under the
            right circumstances the melted iron fills the form and when everything
            cools down, you break off the ceramic and have an iron casting. Once
            you start it, you stand well back and wait for it to burn out. You
            have little hope of putting it out before it finishes and are more
            likely to spread the very hot fire and melted metal around if you try
            to do something foolish like spraying water on it. They used to weld
            railroad tracks together this way at one point in some areas.

            There is also a commercial product called a CadWeld (made by Erico
            Products Inc of Cleveland Ohio) that uses a similar reaction (Cupric
            Oxide and Aluminum) to make melted copper. You can put a cadweld mold
            over the head of a grounding stake, put a bunch of heavy copper wires
            into the grooves in the top, load a charge of the compound and light
            it up.... When it cools down, you basically have a big block of copper
            with all the wires welded to the head of the stake. I have one of
            these left from a few a friend gave to me... They're impressive.

            I could probably scan and post the instructions that come with the
            CadWeld if you are looking for more information, they outline the
            process pretty well. Thermite would be much the same except that
            you'd have to prepare your own molds and mix your own chemicals. Very
            finely powdered aluminum dust (it will hang in the air for several
            minutes if shaken...) can be obtained from a paint supplier, they mix
            it with paint to make metallic colours for cars. Be careful not to
            breathe the stuff though, it will do bad things to your lungs. Rust
            can be made electrolytically and ground in a ball mill to the desired
            consistency. Safety precautions are a must with this stuff.



            On Sun, May 3, 2009 at 12:50 PM, Chris M <chrism3667@...> wrote:
            >
            >
            > can anyone provide a primer on thermite? ---


          • David LeVine
            ... http://en.wikipedia.org/wiki/Thermite is a good one. -- David G. LeVine Nashua, NH 03060
            Message 5 of 9 , May 3, 2009
              Chris M wrote:
              >
              >
              > can anyone provide a primer on thermite? ---
              >
              http://en.wikipedia.org/wiki/Thermite is a good one.

              --
              David G. LeVine
              Nashua, NH 03060
            • Benjamin Bof
              Very good refrence David but beware; It is possible to start the reaction using a propane torch if done
              Message 6 of 9 , May 3, 2009
                Very good refrence David but beware;
                """""It is possible to start the reaction using a propane torch if done correctly.
                The torch can preheat the entire pile of thermite which will make it explode
                instead of burning slowly when it finally reaches ignition temperature."""""
                Regards, Ben
                On Sun, May 3, 2009 at 7:54 PM, David LeVine <dlevine144@...> wrote:


                Chris M wrote:
                >
                >
                > can anyone provide a primer on thermite? ---
                >
                http://en.wikipedia.org/wiki/Thermite is a good one.

                --
                David G. LeVine
                Nashua, NH 03060


              • aaadams@rocketmail.com
                I d only add that apparently (I m convinced of the accuracy but have not done the experiment) ordinary Plaster of Paris can be substituted for iron oxide as an
                Message 7 of 9 , May 4, 2009
                  I'd only add that apparently (I'm convinced of the accuracy but have not done the experiment) ordinary Plaster of Paris can be substituted for iron oxide as an oxygen source with little or no reduction in temperature. Of course, this is for heating only - there is no smelted metal end product. Also, my understanding is that other, more reactive metals (e.g., Mg) may be substituted for Al, but that Al has the best oxidation temperature to maintain the reaction. Finally, a lot of links to this technology can be found on the Web generally and on YouTube (try both "Thermite" and "Thermit" as search arguments). It might be best not to get into an extended discussion of this and similar kinds of reactions on the list.

                  --- In multimachine@yahoogroups.com, Pierre Coueffin <pcoueffin@...> wrote:
                  >
                  > Finely ground aluminum mixed about 50-50 with finely ground rust.
                  > When ignited (as I recall you need a Magnesium strip to light the
                  > stuff), the aluminum will burn, stripping oxygen off the rust to form
                  > aluminum oxide and iron. The process is very, very exothermic (that's
                  > actually an understatement...) So the iron comes out molten. If you
                  > put the thermite on top of a ceramic form and light it up, under the
                  > right circumstances the melted iron fills the form and when everything
                  > cools down, you break off the ceramic and have an iron casting. Once
                  > you start it, you stand well back and wait for it to burn out. You
                  > have little hope of putting it out before it finishes and are more
                  > likely to spread the very hot fire and melted metal around if you try
                  > to do something foolish like spraying water on it. They used to weld
                  > railroad tracks together this way at one point in some areas.
                  >
                  > There is also a commercial product called a CadWeld (made by Erico
                  > Products Inc of Cleveland Ohio) that uses a similar reaction (Cupric
                  > Oxide and Aluminum) to make melted copper. You can put a cadweld mold
                  > over the head of a grounding stake, put a bunch of heavy copper wires
                  > into the grooves in the top, load a charge of the compound and light
                  > it up.... When it cools down, you basically have a big block of copper
                  > with all the wires welded to the head of the stake. I have one of
                  > these left from a few a friend gave to me... They're impressive.
                  >
                  > I could probably scan and post the instructions that come with the
                  > CadWeld if you are looking for more information, they outline the
                  > process pretty well. Thermite would be much the same except that
                  > you'd have to prepare your own molds and mix your own chemicals. Very
                  > finely powdered aluminum dust (it will hang in the air for several
                  > minutes if shaken...) can be obtained from a paint supplier, they mix
                  > it with paint to make metallic colours for cars. Be careful not to
                  > breathe the stuff though, it will do bad things to your lungs. Rust
                  > can be made electrolytically and ground in a ball mill to the desired
                  > consistency. Safety precautions are a must with this stuff.
                  >
                  > On Sun, May 3, 2009 at 12:50 PM, Chris M <chrism3667@...> wrote:
                  > >
                  > >
                  > > can anyone provide a primer on thermite? ---
                  >
                • Eric Smith
                  ... Point taken. Personally, I d investigate http://www.backyardmetalcasting.com/ That was the place I first went, when I was making my gingery style lathe
                  Message 8 of 9 , May 5, 2009
                    >It might be best not to get into an extended discussion of this and >similar kinds of reactions on the list.

                    Point taken. Personally, I'd investigate http://www.backyardmetalcasting.com/
                    That was the place I first went, when I was making my gingery style lathe years ago.

                    And you're right about the thread too... I'll take up any further discussions of the kind, either in e-mails, or on another list, more closely related to casting/welding.

                    Thanks for keeping my enthusiasm in check. I sometimes get a little carried away :-)




                    --- In multimachine@yahoogroups.com, "aaadams@..." <aaadams@...> wrote:
                    >
                    > I'd only add that apparently (I'm convinced of the accuracy but have not done the experiment) ordinary Plaster of Paris can be substituted for iron oxide as an oxygen source with little or no reduction in temperature. Of course, this is for heating only - there is no smelted metal end product. Also, my understanding is that other, more reactive metals (e.g., Mg) may be substituted for Al, but that Al has the best oxidation temperature to maintain the reaction. Finally, a lot of links to this technology can be found on the Web generally and on YouTube (try both "Thermite" and "Thermit" as search arguments). It might be best not to get into an extended discussion of this and similar kinds of reactions on the list.
                    >
                    > --- In multimachine@yahoogroups.com, Pierre Coueffin <pcoueffin@> wrote:
                    > >
                    > > Finely ground aluminum mixed about 50-50 with finely ground rust.
                    > > When ignited (as I recall you need a Magnesium strip to light the
                    > > stuff), the aluminum will burn, stripping oxygen off the rust to form
                    > > aluminum oxide and iron. The process is very, very exothermic (that's
                    > > actually an understatement...) So the iron comes out molten. If you
                    > > put the thermite on top of a ceramic form and light it up, under the
                    > > right circumstances the melted iron fills the form and when everything
                    > > cools down, you break off the ceramic and have an iron casting. Once
                    > > you start it, you stand well back and wait for it to burn out. You
                    > > have little hope of putting it out before it finishes and are more
                    > > likely to spread the very hot fire and melted metal around if you try
                    > > to do something foolish like spraying water on it. They used to weld
                    > > railroad tracks together this way at one point in some areas.
                    > >
                    > > There is also a commercial product called a CadWeld (made by Erico
                    > > Products Inc of Cleveland Ohio) that uses a similar reaction (Cupric
                    > > Oxide and Aluminum) to make melted copper. You can put a cadweld mold
                    > > over the head of a grounding stake, put a bunch of heavy copper wires
                    > > into the grooves in the top, load a charge of the compound and light
                    > > it up.... When it cools down, you basically have a big block of copper
                    > > with all the wires welded to the head of the stake. I have one of
                    > > these left from a few a friend gave to me... They're impressive.
                    > >
                    > > I could probably scan and post the instructions that come with the
                    > > CadWeld if you are looking for more information, they outline the
                    > > process pretty well. Thermite would be much the same except that
                    > > you'd have to prepare your own molds and mix your own chemicals. Very
                    > > finely powdered aluminum dust (it will hang in the air for several
                    > > minutes if shaken...) can be obtained from a paint supplier, they mix
                    > > it with paint to make metallic colours for cars. Be careful not to
                    > > breathe the stuff though, it will do bad things to your lungs. Rust
                    > > can be made electrolytically and ground in a ball mill to the desired
                    > > consistency. Safety precautions are a must with this stuff.
                    > >
                    > > On Sun, May 3, 2009 at 12:50 PM, Chris M <chrism3667@> wrote:
                    > > >
                    > > >
                    > > > can anyone provide a primer on thermite? ---
                    > >
                    >
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