Re: [CAD_CAM_EDM_DRO] Re: melting aluminium

> I do not want to go in the detailed calculations, but if you want to build
> the furnace based on induction, you should start with the complete
> reconstruction of your power wiring, not only in your workshop, but also
> the whole way up to the electricity distributor. The normal power wires are
> not enough, you need MUCH more. Let's say 20 kV/1000 A or similar.

Okay, time for both extremist camps to settle down. First, it's
unlikley any of us will be melting aluminum in a backyard induction
furnace as there are quite a few problems to be delt with. But
second, if we were going to attempt it, we would not need a 20 megawat
power plant all to ourselves.

I recommend anyone interested in this do a deja search on the recent
thread on rec.crafts.metalworking on this subject. The major
highlights were that although it does not require much energy per Kg
to melt aluminum (or even cast iron) it does take quite a bit to
overcome the radiation losses (although less at Al temps than CI).
And small melts have much more surface area that must be insulated
against radiaton per unit volume than large ones, so hobby size
induction furnaces are far less efficient.

If one wants to melt aluminum to make usefull things in limited
quantity, a couple 100 lb propane tanks are probably the way to go...

Has anyone here actually used home cast aluminum parts on a machine,
say for motor mounts or something?

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
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