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  1. #1
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    Default Induction heater/furnace. Are they useless?

    I am not a blacksmith - have only swung a hammer against hot metal a few times


    I have a customer job to create many small steel buttons, rustic door studs. Was planning to bash mild steel rod slugs - 12mm round, about 18mm long - into a die. Some of the buttons need a pattern, so the die will have machined and the slugs will have to be quite hot.

    Probably yellow hot, maybe closer to white?
    Butane or propane won't do it. Maybe MAP or Oxy Acetylene?



    I was thinking about building one of those little induction heating gizmos with the water-cooled coils, that they claim can heat steel to red hot in seconds, can melt small amounts of Gold in a crucible, et c.

    From what I understand of the physics, it is a magnetic effect that causes the heating. Which would stop at red hot (Curie point)?


    Has anyone used one of these with steel?

  2. #2
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    Default

    I did a similar job about 3 years ago, just under 200 fake rivets, with patina. I used Oxy Acetylene because thats what I have on hand. One of the single most frustrating paid jobs Ive done, ever. How are you intending to create the patina?

  3. #3
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    Patina?

    I was contemplating acid, but have a bucket of cast iron filings ready to soak them in with other reagents.


    Better suggestions?

  4. #4
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    Sorry, I meant make them look old and knocked about physically, not so much stained. Kind of like a golf ball. If its not part of your brief please return to regular programming

  5. #5
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    The samples he gave me were actually cast.

    Inside surface typical iron sand casting,
    but outside surface was mostly smooth. Some looked lacquered.


    I did think about reheating the slugs, and hammering them into iron shavings for some texture. It will depend on how efficient I am in making them. If I go the electric induction "furnace" route, that will take extra time to build/setup, but should be faster to heat the slugs and churn them out.

  6. #6
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    Id be looking at something to heat them in quantity, and bribe a suitable helper to grab the next one with tongs and hand it to you for forming.
    Small pot of charcoal and hair drier sort of setup??

    Steve

  7. #7
    BobL is offline Member: Blue and white apron brigade
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    I used an induction furnace at work in the US to melt small amounts (grams) mixture of rock powders and flux in a platinum crucible. It got to about 1500C in very quick time (<minute) and gave off all sorts of RF noise so had to be done inside a Faraday cage. Very spectacular. The resulting "glass bead" was then easily dissolved in strong acids and analysed in a mass spectrometer or a spectrophotometer. Once we tried it outside the Faraday cage and succeeded in damaging a bunch of sensitive electronic instruments in the lab next door which cost a couple of grand to fix

  8. #8
    BobL is offline Member: Blue and white apron brigade
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    Default

    Here's one on Banggood
    Claim is 1200C in 5 minutes

    Capacity claims is 3kg gold, or 150 cc - not much really,
    Screen Shot 2021-09-22 at 5.03.02 pm.png

    https://www.banggood.com/MM-TC-3000-...N&rmmds=search

  9. #9
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    Quote Originally Posted by BobL View Post
    Capacity claims is 3kg gold, or 150 cc - not much really,
    $235,800 in fact!
    Chris

  10. #10
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    Bob, thanks for that link, 5000W is a decent amount of power/heat,
    though at nearly $2000US is out of my price range for one small job



    1200C would certainly be hot enough for soft working of steel,

    but I suspect getting that hot requires the graphite crucible;
    graphite gets super hot, metal sitting on the graphite heats up,
    and a lot of heat radiates out of the top of the crucible.

    (which is why they have a quartz thing to hold the graphite thing)



    Also, 1200C in 5 minutes? Sounds like nicely made up round numbers, doesn't it?

  11. #11
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    Default Finally found some useful info

    https://spaco.org/Blacksmithing/ZVSI...eaterNotes.htm

    Basically, his conclusion is that they are no good for forging steel.




    Also found some good forums that talk about melting alloys for casting, and annealing bullet casings:

    https://highvoltageforum.net/index.php?topic=530.80

    https://forum.accurateshooter.com/th...3908353/page-2

  12. #12
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    Default

    For many times less than those sort of prices you could build a simple gas forge.

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