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Thread: Metal melting: using fuel or induction?

  1. #1

    Metal melting: using fuel or induction?

    Most forumers here, including myself, use fuel for melting metals as electric melting with an electric Kanthal furnace is too slow and induction too expensive.
    On the site copper.org I found:
    Quote Originally Posted by copper.org
    In contrast to aluminum die-casting, where gas or electric resistance furnaces are typically used, the higher melting temperatures associated with copper mean that induction furnaces are generally used for the melting of copper.
    Well that seems valid for commercial copper melting, but for us, amateurs, induction furnaces are, despite being much cleaner and much more efficient, way too expensive, unless you use the ebay one I posted recently for very small quantities.

    What are your opinions ?

  2. #2
    I think you pretty much summed it up. The required power supply is inherently expensive and adjustment required with the changing inductive load makes controlling it complex. Even with carbon electrode electric arc you still have an expensive power supply to deal with, at least at any meaningful melt capacity. I suspect even big capacity welding power supplies still may struggle with that continuous duty cycle.

    Best,
    Kelly
    My furnace build ----- I toil and fettle then foam turns to metal!

  3. #3
    Senior Member Spelter's Avatar
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    What copper.org is saying is, induction is easier (as an industrial operation) than resistance at copper temps. It does not mention combusted fuel.

    In terms of effeciency, resistance trumps induction; all of the power drawn is inside the furnace. The problem with resistance heaters is the hazard of the resistors melting themselves.

    Heating with electricity is inherently more expensive than heating with fuel. Where electricity shines, is keeping the heat from escaping (easy to insulate). Since the heat doesn't escape, less is needed. It can be competitive when done right.
    "The former lives of objects need not interfere with their current use."

  4. #4
    Used motor oil or veggie oil is KING.. If it's free, it's for me.
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  5. #5
    Senior Member Spelter's Avatar
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    It would be expensive to tool up for an eighty pound casting with induction. But for small work, you can cast ultrapure metal in minutes from a cold start...in your livingroom.
    "The former lives of objects need not interfere with their current use."

  6. #6
    Quote Originally Posted by Spelter View Post
    It would be expensive to tool up for an eighty pound casting with induction. But for small work, you can cast ultrapure metal in minutes from a cold start... in your livingroom.
    For me, melting small quantities (up to 400g) I do indoors using a natural gas fueled furnace, not in my living room, but in a hobby room equipped with a fume hood. When induction becomes feasible, I will join the club. Currently, the 1000W eBay induction kits allow one to melt only small quantities of aluminum, not copper or steel. For the latter I use electric arc furnace melting using my DC welder.

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