Building an induction furnace

[john bunsenburner]

The name says it all, I looked at some vidios on youtube where people melted metal using an induction heater and the idea struck me to do the same, I read the wikipedia artical on it and pretty much anythign else i could find and it seems like a nice little project, all comments are apriciated and i am very happy with any advice. Knowing the people on this forum atleast one person tried making something like this and so i thought i would share this thought with you. Thank you fro all your comments and advice in advance.

[rp181]

Do you have any power electronics expierence? One capable of melting metals will take a LOT of power, big IGBT's and a water cooled coil (most likley). Just to make sure i know what type of furnace your talking about, can you post a link?

[john bunsenburner]

http://www.richieburnett.co.uk/indheat.html From what i read i can power it with the normal 240volts from the house hold poer supply, just have to some how change that to hihg frequency, you see i am fairly new to electronics...

[rp181]

Good luck then =p
Even at 240v (im in 120v land) It would take considerable current to melt stuff. To get the high frequency, you use IGBT's switching rapidly. I say dont even attempt it if you dont have any expierence with power electronics (or electronics at all).
What did you want to melt? (size, metal type, application)

[john bunsenburner]

Lead and aluminium, small batches in the 1pound range, fairly small pieces no big chunks...Does that help? It seems fairly simple to do, or is it just me?

[rp181]

Nope. That kills your project even more =p
Non ferromagnetic metals are much harder to heat. Aluminum would take a lot of power.
Also, smaller pieces has two sides:
The good side, lower power is needed.
The bad side, you need a higher frequency, which means more heating of IGBT's, Bigger heat sinks, and larger IGBT's.

[john bunsenburner]

So if I used large pieces of alli that would be better, further more what you are saying is only 90% true: steel(for example) looses its ability to be magnetic at 700°C there is still quite a bit to go from ther euntil it melts, alli on the other hand melts at around 700 already and the eddy currents should be eanopth to melt the alli and lead. I lov these disscussions they always help!

[rp181]

That is true, but that first 700 degrees is alot =p One guy made a steel bolt melt with 2kW input power. Only thing to do is try =p
Lol, this made me want to make one =p and i ordered some parts a couple days ago that will let me build it (comming day after tomorrow) . Ile let you know how it goes.

[john bunsenburner]

Ok, happy this inspired you, talking of parts: Waht parts would be vitally nessasary, i know this is a dumb question but i want to write my physics project on this and a model is always very convincing, and i want to try it out, oh and where could i get electrical parts, and what cost would you estimate?

EDIT: I know i need a power supply a cable of some sort that will plug in to the power supply and a coil(which i am very unsure of). Is there anyhtign else?

[microman171]

Order them from digikey, mouser? I'm not so clued up on the electrical outlets in the US.

I too have looked at these before, IGBTs are definitelyy the way to go. They are pretty much more 'beefy' transistors. I say use 555 timers to oscillate.

Go to a plumber for the copper for the coil, and I dont think soldering would be up to the job, I say flatten the ends and use bolts.

I cant answer your question on cost, I just know it would cost about $100 NZD to make one almost capable of melting something.



On another note, I melt aluminium with a coffee can and wood/charcoal/coal. Why do you want to use induction heating?

[john bunsenburner]

I am starting to be put of by the idea... Really all i wanted was lots of heat and no large amount of waste(so woad or charcoal is not up to the job). I tink i will jsut make a propane powered furnace, easyest way to go about things but rp181 you have to tell me how things worked out. I have too many projects right now, first priority is my first spud gun, next will be the furnace then a biodiesel reactor, a compressor and then a steam engine, that will keep me busy for a while.

[rp181]

You need a signal that gives alternating pulses. For this, you can use a TL494. The outputs of the TL494 connect to the gates of the IGBT (look for one rated for high frequency high current), and the power connects to that. I dont feel like going detailed now, so ile pm ya later (tomorrow) with parts and stuff.

[john bunsenburner]

ok sure thank you.

[TurboSuper]

Just out of curiosity, why an induction heater? There are alot of other induction-based projects out there which work with less dangerous currents...

[Gippeto]

If you've been around the backyard metal casting site, you should have seen this, they don't get much simpler.

http://www.backyardmetalcasting.com/oliverburner1.html

Or, just get one of these;

http://pacificcoast.net/~kerslake/Bronz ... Burner.jpg

Unless you plan to run a car, biodiesel can be made in an old blender in no time. If you do plan to run a car, a metal 20 litre pail will make a very good small reactor.

You do understand that sodium methoxide is VERY NASTY stuff? The parent ingredients aren't to be taken lightly either.

Please take the time to read these.

http://www.methanex.com/products/docume ... nglish.pdf

http://www.seas.upenn.edu/~nanofab/chem ... e_NaOH.pdf

http://www.sciencelab.com/xMSDS-Sodium_ ... de-9927332