• Devial@lemmy.world
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      1 hour ago

      Yes it would. Adding material generally makes thermal conductivity worse. There is no material with negative thermal resistance, so adding more will always increase thermal resistance by at least a bit.

      The only exception is 3D geometries, where an increase in surface area due to the extra material can outweigh the effect of the added material, and lead to a net increase in thermal transfer.

      This can lead to a paradoxical effect, where ADDING insulation around a pipe leads to HIGHER transfer than with less insulation material, because the added material increases the exterior diameter, and therefore surface area.

      (Heatsinks are also a good example. It is more material than just the component by itself, but increases surface area by such a massive amount that it more than outweighs the added material)

      • TargaryenTKE@lemmy.world
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        2 hours ago

        Brass is an alloy where the two metals are melted together, the pennies are a zinc core with a thin copper coating. Think of the former as a chocolate/vanilla swirl and the latter as a vanilla cone dipped in chocolate but ya know, with chemistry magic going on

    • OwOarchist@pawb.social
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      22 hours ago

      For most of them, yes. But if you get old enough pennies, they’ll be pure copper.

      However, it’s easy to tell just looking at this that many of these pennies have the newer design, so they’re definitely only copper plated.

        • OwOarchist@pawb.social
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          20 hours ago

          They’re all real copper on the outside. Even the fake ones are copper plated. So the surface you’re pissing on is copper regardless and would show the same reactions.

          If you want a simple way to find pure-copper pennies, you don’t need piss – just look at the dates on them. Dates before 1982 will be pure copper (with a few rare exceptions), and after 1982 are all copper-plated zinc (with one rare exception).

            • OwOarchist@pawb.social
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              5 hours ago

              Yeah, those are one of the pre-1982 exceptions.

              There are also some extremely rare copper plated aluminum pennies from the 70’s out there. (That was done as an experiment for reducing the cost of the penny, and they were never supposed to go into circulation. But a few of them did end up in circulation and are very valuable among collectors today.)

  • Imgonnatrythis@sh.itjust.works
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    20 hours ago

    Feeling weird/outed this is a shitpost. Just last year searched for copper bottomed carbon steel pan for this exact reason. Didn’t find anything, but I still like the idea. Carbon steel is pretty shit at conduction.

    • davetortoise@reddthat.com
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      17 hours ago

      Copper pans exist but they can be a pain to cook with. The high thermal conductivity means they heat up much faster than you expect, so it’s easier to accidentally burn stuff, and they also cool down much more quickly once off the heat which can also be annoying. Plus you need to worry about oxide formation and food sticking much more than you do with steel pans.

      • Imgonnatrythis@sh.itjust.works
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        5 hours ago

        I know but a copper bottom to improve conductivity really helps carbon steel pans which are really bad about getting hot spots. I have a copper plate I put under mine and it works great. You don’t want a pure copper pan as it doesn’t have the nonstick properties, easy maintenance, and it would also be expensive. But a coper bottom would be nice.

        • davetortoise@reddthat.com
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          4 hours ago

          I don’t want to contradict your lived experience but I’m quite sceptical that the improvement is real. Adding a layer of solid material between the heat source and the steel can only reduce the amount of energy transferred to the steel, as some will be absorbed by the material no matter how conductive it is.

          • Devial@lemmy.world
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            1 hour ago

            In this case it isn’t about improving heat transfer through the bottom of the pan, it’s about improving heat transfer across the bottom of the pan.

            The heat will travel through the pan more slowly because of the added material, but due to coppers extremely high heat conductivity, the copper base will heat very evenly, even if the heat source is unevenly applied, and therefore evenly transfer that heat through the steel layer.

          • Imgonnatrythis@sh.itjust.works
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            3 hours ago

            If you have the materials can avoid taking my word for it. Use a temp gun and check 5 spots or so on a carbon steel pan on the burner. Use a larger pan and smaller burner to exgaerate the effect. Repeat with a copper plate (needs to be at least size of pan bottom, bigger doesn’t seem to detract from effect. You’ll see much more consistent heating. Works for cast iron too - actually more notable at first and the the effect diminishes somewhat as the thick iron holds onto heat and becomes more uniform (still helps though)

            • davetortoise@reddthat.com
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              3 hours ago

              Oh right! I didn’t realise you were talking about distributing heat more evenly, that’s my bad. Yes I can definitely see that being effective.

              • Buddahriffic@lemmy.world
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                3 hours ago

                Another version that can work is if you have two pans where the bases are both say 5mm, but one of them is all steel while the other is 3mm copper welded to 2mm steel, the copper one should heat up faster than the all steel one. No idea how well copper welds to steel though.