DIY Induction heating

Once you have made your ignition coil, you may want to try making an induction heater. Here is how they work:

When an alternating electric current is passed through a coil, the coil creates a magnetic field. The magnetic lines of flux cut through the air around the coil. If a ferrous material, such a solid bar of iron is inserted into this coil, certain effects known as eddy currents are induced to flow in the metal bar. This causes localized heating, and ultimately heats up the metal bar.

How to make an induction heater.

28 thoughts on “DIY Induction heating

  1. I’ve seen this in use in industry to melt a glass compound onto metal parts for use in the chemical industry. The parts were cylindrical and coated with the compound like you coat fish with breadcrumbs, then fed through the coil to heat p the metal and fuse the glass onto it.

  2. I’ve seen induction heating used in valve (vacuum tube) manufacture, for the glass-to-metal seals. They used it because it’s very clean, unlike say, a propane torch flame. It’s also possible to heat something which is inside a (non-conductive) vacuum envelope.

  3. Update: I just tried this with a power MOSFET (IRFP450) and a signal generator (HP 3310A). The coil was about 25 turns of 1.3mm diameter enamelled wire, wound using a AAA battery as a former. I heated up a paper clip, but that was at the limit of my power supply. More power, Igor!

  4. When induction heating is used in industry to melt metals etc, the coil is usually made out of copper pipe instead of wire. Cooling water is run through the pipe, to prevent damage to the coil. Thus you have water, heat and high voltage all in one gadget… better be sure nothing is leaky or something nasty might happen :-)

  5. @Aamund

    I have seen commercial induction heating in action, but I didn’t realize there was water in the coil. Thanks for the info.

    1. (Assuming you’re referring to the water-in-tubes thing)

      The water is less conductive than the copper, so the electricity will ignore it. Anyway, what would it short out with if it’s only inside the coil?

  6. i am making an inductor heater as my project in university. but i am having problems with the calculations. can anyone help?

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