1000W Induction Heater

[Tim Williams] likes to heat things up with this induction heater he built. At peak it can use 1000W and as you can see in the video, that’s more than enough power to heat, burn, and melt a plethora of different objects. The case design uses a center divider to isolate switching noise from the magnetic field with the whole unit housed in aluminum because it won’t heat up from stray magnetic fields. He’s selling plans and kits in case you want one, but we just don’t know what we’d use it for.


[Thanks Arcen]

60 thoughts on “1000W Induction Heater

  1. Mike said: “…we just don’t know what we’d use it for.”

    I can think of several things to use this for:

    a) heat the interior of homebrew vacuum tubes during final evacuation to drive off adsorbed gasses on electrodes

    b) melt metals in small graphite crucibles for casting machine parts or jewelry

    c) applying heat to temper knives, machine parts, or custom springs

    d) annealing small metal parts to reduce/relieve work hardening.

    1. yes, many have posted youtube videos of their induction furnaces melting (and even levitating molten blobs of) aluminum. Works with copper too, but due to the lower reaistivity, copper takes a higher induced current, or will take longer to heat (less efficiently).

  2. @tanjent: Not everything has to be so black-and-white. I know there have been cases of people dying from zinc inhalation, but as long as it’s done with care (do it in a ventilated area or outside, and don’t intentionally breathe or smell the smoke), it is perfectly harmless. I am in the process of building a gokart with a galvanized tubing frame, and after having welded plenty of the stuff, I am happy to say I do not feel dead at all.

    1. As an ex-certified welder, I have had the displeasure of having to weld galvanized steel many times. You can be killed by the fumes, but it takes a lot to do that job. Most common is zinc poisoning, which can be fixed by drinking whole milk. Be prepared, you will throw up after. The proteins in the milk absorb the zinc from the galvanizing and you get it our of your system by throwing up. Trust me if you are suffering from it, you will throw up, no choice. I suffered from this while in the Air Force working on some material that had to be brazed. Hospital sent me home with orders to drink as much whole milk as I could and didn’t warn me about what would happen. Next day I was feeling better and went back to complain and was told that it is a normal reaction, they didn’t inquire at the time if it was my first time with zinc poisoning. Keep clear of the yellow-white fumes and whatever you do, do NOT breathe in the white feathery pieces, they will make you more than just sick.
      Warning to the wise.

    2. I personally cut too much galvanized steel when younger. I got very sick my grandfather was a welder and to me they used to do it outside and drank milk? I don’t know why but he died at 97

  3. Use? Very simple – forging. Heat treating anything with something that powerful would be overkill (and frankly require more skill with perfect timing than I have, since the temperature required to temper steel is < 600 degrees), but it would be perfect for heating steel/iron to good working temperatures very quickly. Ideal for bladesmithing.

    I would vote that unless you know exactly what you're doing, stay away from heating/welding galvanized steel. The risk isn't worth the reward – particularly since you loose the benefits of galvanized steel when you do heat it to that point.

    Plus, since it's a heavy metal, the effects will add up over time – a hundred small doses can kill you as effectively as a single large dose.

    1. This may be a little late; but, heat treating and tempering are not the same thing. You are correct that tempering is done well below 600 but the initial hardening requires temps from 1200 to near 2000 depending on the alloy and hardness required. Something for which induction heating is ideal and indeed for which it has been used for many years. Besides the relative ease and quickness over using a forge or kiln, induction has the added benefit of being able to be tuned for surface hardening which results in the equivalent of differential tempering and indeed obviates the need for a tempering phase altogether.

  4. @op: I think you can achieve the same with a Prescott P4. AMDs are good too. I have an old laptop with an Athlon XP that would be good for this and is portable too :P

  5. @falcolas – I used induction heaters to heat treat steels at my job for almost thirty years. Yes, it takes a bit of skill to do it properly, but it is a very viable way to do this because the core of the work heats along with the outside evenly and quickly. This is how one prevents decard.

    Furthermore, one should never heat treat galvanized steel under any circumstances above 350F, as not only will the coating be damaged, but the zinc will migrate into the parent metal giving the item a list of undesirable properties.

  6. Wow, I can honestly say that it’s been years since I’ve seen such an unsafe setup. I don’t even know where to begin. Inhalation, fragmentation, electrocution, etc… Heating galvanized pipe, to the point that the galvanization is smoking? Big no-no. Do this enough times thinking it’s not a big deal, and you’ll be wondering why you have psychosis and heart disease in 5 years. Let’s hope there are no kids with access to this ‘lab.’ How many amps did he say he was pulling again? Yup, this guy is begging for a ‘hurtin.’ If he keeps up these habits, odds are he’ll be crazy, missing and eye, severely burned or just down right crispy and dead in due time. I love the “smarts” in this community–and some of the people experimenting are clearly brilliant–but I’m seeing a pattern across many of these posts of throwing safety to the wind. Not having been hurt badly doing foolish things in the past is no guarantee of not being hurt badly doing foolish things in the future. Ever drop a screwdriver on a high-amperage source? Think: fragmentation grenade.

  7. I love induction heaters and miss working with them. The coil looks a lot like the induction coil on some 80-150kW plasma torches that were used in the PECVD process at an optical fiber facility where I was employed.

    Great project Tim!

  8. Awesome!
    By the way , if any one is concerned about safety; just use the correct safety precautions necessary.
    It is not like working/forging metal is overtly safe to begin with.
    Just consider that people that work in foundries use a lot of safety gear ventilation and lots of practice before being good at it.
    For those that know what they are doing, this looks like a real nice start.

  9. DUH!

    Been there, done that.

    1. Build a resonant circuit out of the working coil and some WIMA (metal-foil, “FKS-2” e.g.) capacitors.

    2. Couple that to a push-pull MosFET stage running off 325V EU / 162V US power. Coupling must be done via a series-coil to filter out the hard switching harmonics.

    3. Use a constant-current-mode to drive the push-pull stage. An SG3525 is the right integrated circuit to do the job.

    4. Enjoy!
    (And don’t kill yourself)

  10. Hi guys,

    Thanks again for putting up my project :)

    The most recent video (you can find it on my YouTube channel) is the best, it shows the control circuit in action, and the project is nicely boxed in a professional chassis. I also melted cast iron. :)

    Some comments on comments:
    I took adequate precautions when heating the galvanized pipe. Obviously, you can’t see my face, but I was wearing a mask. I also left the area for several hours afterwards to let the fumes clear out. I know personally that I am practically immune to zinc fumes, so it doesn’t seem to matter much for me. Some people are dangerously allergic to the fumes, so you should never be careless. It’s bizarre how zinc fumes seem to affect different people so differently, and anything so curious is sure to draw lots of comments…

    @Ulrich: that seems to describe the LLC output network, which I decided earlier (page 7-8 on my website) sucks, at least for the values I was using. This setup uses an output transformer and series resonant tank, which operates much more smoothly. I used a TL494 oscillator, which is similar to the SG3524 (the 3525 with uncommitted transistor outputs instead of totem pole outputs).


  11. Think the alcohol stil idea would cost you a bunch of money in electricity bills.

    I do like the idea of metal forging. Could you simply place a steel crucible of aluminum scrap inside and have the same results?

    To whoever mentioned hot dogs. Put it on a coat hanger and cook from inside out. :) Crap, now I want a hotdog.

  12. neat, i can think of a number of uses.

    Unsticking cold-welded nuts on equipment comes to mind, also the basic circuit is very similar to the primary of a Tesla coil so many of the same techniques can be used.

  13. Why in H e double hockey sticks are you heating galvanized pipe?! I don’t get how you could be smart enough to build an induction heater from scratch, but kill yourself with a whiff of zinc smoke!

  14. I find the fact that so many people here warn against life threatening risks of exposure to zinc fumes, while the actual safety sheets describe only relatively minor metal fume fever, puzzling.

    1. Zinc fumes can sure kill you dead, but it might take a bit to do it. Though from one who has inadvertently taken a snoot-full of accidentally vapourised cyanoacrylate, by the time it happens and you realised you messed up, the difference between “oh, I’m going to be sick tomorrow” and “oh crap, I’m dead in a few minutes” can be down to something as mundane as temperature. It just comes down to knowing what you’re working with and being sensible about how you work with it and protect yourself while you do so, even if the MSDS says ‘minor xyz’ – if something potentially makes you sick from exposure, that’s pretty much a sign to at least try to mitigate exposure to it while working with it

  15. can this be used to melt glass? and if not what about colored glass that has a lot of metals in in it? maybe this can heat a crucible with glass in it or would this work if you heated up the glass in a kiln first to where the glass was past the annealing point and conductive?

  16. Aluminium isn’t strictly immune to developing eddy currents, but it since free magnetic fields don’t like to travel in aluminium as much as they do in steel, it heats up less.

  17. Well I can think of a number of uses in say the automotive world….for instance;

    1. heating around a windshield or other glass to soften up the butyl and make removal easy.
    2. heating small plastic parts to help restore to normal shape, eg, dash panels, door panels, bumpers etc
    3. heating trim to soften the adhesive for removal
    4. heating a stuck nut where flame would be hazardous

    These are just some of the ideas I could use a piece like this for…thats just me…

    Boiling cold coffee….

    Trust me this would be great for the automotive work I do…where do I get plans?

  18. Eddy currents will form in anything conductive, but eddy currents in aluminum or copper just flow, without much resistance, which means little heat. Iron and its alloys aren’t very conductive, so when you hit them with a current (eddy or otherwise), that current starts turning into heat very quickly. You can inductively heat aluminum, or any other conductive material, but won’t be as easy, and may have additional problems.

  19. I’m perplexed and fascinated. I can’t understand the basics here. What’s in the copper pipe? Why is electrical noise, switching noise, and harmonics an issue? What role does magnetism play in the production of the heat?

    I know I’m way out of my league, but I’m curious. Any info appreciated. Thanks. David

  20. Hi Tim,

    I have a use for your heater system that will sell thousands. It will have to heat copper and aluminium though.

    Give me a shout and perhaps we can work something out.

  21. Hi,

    I’m working on Induction Heater own my. I’m finishing circuits… almost ready… But i have a question about the water across of pipe: This water should be desmineralized?, to not conduct the electricity flowing through the coil…

    Personally i think the electricity just flows in the pipe surface,due the theory of Penetration depth.

    used, ordinary water?

    Sorry for my english, I’m student of Ing. Electronics from Venezuela. If you want we can change what we learn by doing the heater, I can show you my circuits.

  22. How about this:
    Tungsten Crucible
    Melt glass with the hot tungsten into a form
    Sell the new glass artifact
    Make lego-bricks and stack them to form whatever you want

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