Q&A for How to Anneal Copper

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  • Question
    Can copper be annealed without water quenching? Is the quenching a way to work with it faster than waiting for it to cool in the air?
    Community Answer
    Yeah. You do not have to quench it, but quenching also helps blow off some of the oxide that forms during annealing. Some alloys like all types of steel, and antimony/lead alloys harden if you quench them.
  • Question
    Can I anneal copper tubing with a propane torch?
    Community Answer
    Yes, but it will take much longer to get red hot compared to using MAP gas or oxy/acetylene.
  • Question
    I heard that running my microwave with copper in it will remove any bad smells and stains. Is this true?
    Community Answer
    No, it's not. Someone is trying to get you to damage your microwave. Microwaves work by exciting water particles, so a microwave actually will evaporate water. Microwaves would do nothing to the copper, except for produce sparks.
  • Question
    Can I anneal any grade copper?
    Community Answer
    Yes, but doing so changes the characteristics of the copper. Be careful, and make sure that the copper will still be within the parameters required for whatever job is expected of it. Also, not all copper products are pure copper, and those that aren't will react differently than those that are.
  • Question
    Can I use a gas cylinder of LPG for heating copper?
    Community Answer
    Assuming you mean using an LPG-fueled torch, yes, you just have to be able to heat the copper red hot.
  • Question
    Can I use annealing with other metals like iron or nickel? If so, then what temperature?
    Community Answer
    Nickel can be annealed using several different methods; the torch method is the least desirable since it heats unevenly and will form heavy oxidation on the surface. Open annealing of "pure" nickel is done from 1500 F to 1700 F. Leave it at that temperature for a while to fully soften so that crystals can reform. Note that different alloys of nickel have different annealing temps and will behave differently in a quench; "pure" nickel (nickel 200) will anneal while other alloys will harden or temper. Iron can also be annealed, at 1600 F - 1650 F, but it should be allowed to cool slowly afterwards rather than quenched.
  • Question
    Should I always turn off acetylene before oxygen?
    Community Answer
    Doesn't really matter. One benefit in turning the acetylene off first is that you avoid the soot produced from burning acetylene with too little O2.
  • Question
    How do I return copper back to its hard state later after it is annealed?
    Community Answer
    The process of hardening copper is called "work hardening". Bending, hammering, and tumbling in a tumbler are all methods of hardening the copper.
  • Question
    How do I know if I need to anneal copper?
    Community Answer
    Do you want it to be softer or harder? Harder is more brittle, softer is less brittle but easier to bend. Annealing lets all of the crystals in the metal reform, so they can be bend up again, till they are fragile, but harder again. It is a cycle you go through when you are cold forming something. (For making a copper rose, I pound on the copper till it gets hard to work, anneal it, then beat on it some more till I have what I want. If I could not anneal it, my arms would be much more worn out after the work. That is, I am not beating on it hot, it is room temperature, but after so many beatings, it gets hard and brittle, so I anneal it again.)
  • Question
    Why can I quench ferrous metals, but not nonferrous metals? Why is it okay to quench copper, but not carbon steel?
    Community Answer
    You can quench any metal through the act of plunging it into a bath of oil or water when it is hot. If you want to anneal it, though, you have to know what metal/alloy you are working with. You quench carbon steel to make it harder. It all has to do with how large the resulting crystalline structure is. Fast cooling results in a fine-grained structure, thus a hard but brittle material. Slow cooling allows the crystal grains to grow to a larger size, which results in a more malleable annealed steel. So, to anneal a hardened steel, you heat it red and then let it cool very slowly. It doesn't matter whether you quench copper, as just the act of heating it red anneals it.
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