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  • aluminium foam

    How is it made?
    Can it be machined?
    Is it expensive?
    Can it be made at home?

  • #2
    That's interesting. Can't answer any of your questions but I have one of my own...
    What does the end-view of that piece look like (cross section)?
    Thanks,
    Gordon

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    • #3
      I first saw aluminum foam in about 1960. A fellow student at university got a piece from his dad. The story that I was told was that it was developed at NRC while working on stuff for the Avro Arrow. They were looking for a way to produce seamless, rivetless wing sections by moulding. It did not work.
      I believe that it is foamed with a high-temperature sulfur-based foaming agent, likely similar to the one used to produce Foamglas. They both stink!
      Is it expensive? Almost certainly, (after all, it is likely made from molted BILLET!)
      Can it be made at home? Not likely, although a gassey casting MIGHT be called foamed aluminum!
      I have always thought that this was an idea that just never went anywhere.
      Duffy, Gatineau, Quebec

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      • #4
        http://en.wikipedia.org/wiki/Metal_foam

        Wiki has some information and dates.
        "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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        • #5
          Where did you get a picture of my welding?
          Any products mentioned in my posts have been endorsed by their manufacturer.

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          • #6
            Yes, HOW IS IT MADE? Precisely, how was this sample made with foam in the middle and fairly consistent solid sides? I mean, the obvious answer of "blowing a gas through the molten metal" does not answer that question. Was this made in one step? Or is it an assembly of two sheets of solid metal with the foam metal between them? The flat sides of some of the bubbles seem to support this sandwich method. But how would you do that? If it is assembled, the welds look almost perfect.

            Probably getting into trade secrets here, but something must be known about how it is done.


            Originally posted by Elninio View Post
            How is it made?
            Can it be machined?
            Is it expensive?
            Can it be made at home?
            Paul A.
            SE Texas

            Make it fit.
            You can't win and there is a penalty for trying!

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            • #7
              Ok I know a bit about how they make closed-cell skinned foam out of styrene-plastic.

              The outer layer "skin" is created by maintaining the die/mold at a specific temp. Basically, the skin forms first while the bubbles churn within.

              If you get blowout or skin ruptures you adjust the die/mold temps, then you adjust your fill-rate/extrusion rate, finally you adjust your chemistry.

              One assumes the principles are the same for metal-foams just at different heats and chemistry.
              "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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              • #8
                I would envisage casting the part with mould wall and injecting gas to foam the middle of the material when an appropriate skin thickness had solidified. That would probably be far more reliable than trying to fabricate a composite structure.

                Edit:- Like what Grind-Hard says :-)
                Location- Rugby, Warwickshire. UK

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                • #9
                  Shame on you guys for not sussing the production methods out before this , It is made in a top secret underground factory somewhere in the mid west of the U.S A, I might get into a lot of hassle for giving you all the low down, It is simple Great big economy size wasps, making nests in the stuff , The workforce are very highly paid, for danger money.

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                  • #10
                    Originally posted by oil mac View Post
                    Shame on you guys for not sussing the production methods out before this , It is made in a top secret underground factory somewhere in the mid west of the U.S A, I might get into a lot of hassle for giving you all the low down, It is simple Great big economy size wasps, making nests in the stuff , The workforce are very highly paid, for danger money.
                    ABSOLUTE Bull**** and you know it.

                    This was outsourced years ago as Asian Hornets have a much lower cost per unit than American Wasps.
                    "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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                    • #11
                      I do know that there is a great deal of interest in producing foamed metals in micro-gravity conditions. That would be one of the highest priority applications for orbital manufacturing along with production of medical materials including drugs where convection does not cause separation of the constituents. They have been discovering some unanticipated effects that operate at high temperatures (and low) when gravity is absent. Flames in particular work in ways not at all predicted. A little known form of combustion of plain diesel fuel was recently verified on the ISS. The fuel actually burns at a temperature of about 120C, just above water boiling temp.

                      Cool Flames and Autoignition: Thermal-Ignition Theory of Combustion Experimentally Validated in Microgravity

                      At temperatures as low as 120 °C, fuel-air mixtures react chemically and produce very weak flames called cool flames. Unlike conventional flames—which generate large amounts of heat, carbon dioxide, and water—cool flames generate very little heat (e.g., a temperature rise of only 10 °C), carbon dioxide, and water. At low temperatures, the fuel and oxygen molecules have little energy and therefore do not react vigorously. The reaction never proceeds to complete combustion; rather, the molecules break down and recombine to produce a variety of stable chemical compounds including alcohols, acids, peroxides, aldehydes, and carbon monoxide. The weak temperature rise is produced by the breaking and reforming of the chemical bonds.
                      http://www.grc.nasa.gov/WWW/RT/RT1999/6000/6711wu.html

                      Foamed metals would be of high value if the material can be held in zero gee for a long enough time for the foam to arrange itself in a least energy packing configuration, unlike the sample shown. Such a configuration would produce predictable and consistent properties, the lack of which makes current products much less useful.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        Originally posted by Grind Hard View Post
                        ABSOLUTE Bull**** and you know it.

                        This was outsourced years ago as Asian Hornets have a much lower cost per unit than American Wasps.
                        Still bigger labor problems using Asian hornets ,Grindhard, They are bad tempered, vindictive & stubborn , The work study guys found, You will never get inside the mind of a hornet , Better importing some of our Scottish wasps, "Dear little things" Speak to Alistair Hosie he has a cheap source for them & stop outsourcing work, & bring jobs back home!

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                        • #13
                          If you read through this long list there may be information on foamed materials. I haven't looked yet.

                          http://www.grc.nasa.gov/WWW/RT/RT199.../contents.html
                          Free software for calculating bolt circles and similar: Click Here

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                          • #14
                            Originally posted by winchman View Post
                            Where did you get a picture of my welding?
                            That was my first thought, Someone just forgot to turn on the shielding gas when they welded those two sheets of steel. :P
                            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                            • #15
                              I guess that, the heat dispersion in aluminium occurs so fast, that heating the mold or cooling it would not be like pouring bubbly aluminium onto some chilled surfaces. There's no foamy steel and aerogel (foamed glass) has much smaller pores. It's used for sound and heat insulation, and outperformed honeycomb aluminium, which has been used for a long time (in crumple zones for example). The homogeneity of the foaming agent is amazing - look at some larger pieces, they are very consistent.

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