# Homemade Tools >  12kw Induction heater

## imsmooth

Several years ago I built a 12kw induction heater for a blacksmith. This unit was able to melt and boil steel within seconds. For those of you who do not know what an induction heater can do you are in for a real treat.

The tutorial along with schematics is here.

Here is a 

 of a small 3kw unit I built.

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kbalch (May 6, 2014),

stan the toolfool (May 9, 2014)

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## kbalch

Thanks imsmooth! I've added your 12KW Induction Heater to our Electrical and Heating and Cooling categories, as well as to your builder page: imsmooth's Homemade Tools. Your receipt:





 






12KW Induction Heater  by imsmooth 

tags:
power supply, heater

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## DIYer

I've been fascinated by induction heaters since I learned about them. Great contribution!

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## BenH

I really like that and a great write up thanks.

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## imsmooth

I tried to make a tutorial for both beginners and advanced users. When I first got interested in this there were very few articles explaining the theory. One of the problems many face with higher power units is an understanding of why these circuits blow up at the higher energy levels. For those who have not seen it yet, I've included many oscilloscope tracings showing "bad" waveforms and how to diagnose the issue. Eventually, I sold my unit to a blacksmith who now uses it to make swords.

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## jmart235

I wonder if you were correct when saying you were heating aluminum.
I have worked around many aluminum furnices and when Aluminum is melted it still retains a silver color. It melts far before it reaches bright red, and never white hot.
Perhaps it was stainless? both aluminum and stainless do not couple well with the current in the coil. Both will take longer to get to temperature.

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## hemmjo

That actually appears to be a common bolt screwed into a "connector" nut like commonly used to join threaded rod etc. It would be zinc coated which would explain that deadly toxic white smoke that came off when it was initially heated. The steel would respond well to the induction heater.

It is an impressive build, I would love to have time to play with one some day.

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