Melt Metal in your Microwave

[sevisehda]

I found a great link today. This guy melts metal in an unmodified microwave with very basic supplies.

http://home.c2i.net/metaphor/mvpage.html

Could make casting blocks easier.

[nicozeg]

Very good link!

Now who wants to borrow me his microwave for some tests?

[bigben2k]

The Method in Brief
A wax object is prepared, attached to a hemispherical wax cup.
A second blank wax cup is prepared.

Both waxes are coated with a patent ceramic shell slurry containing some graphite.

These are then stuccoed with a magnetite sand.

Further layers of normal ceramic shell slurry are applied and stuccoed with molochite grain to build up the shells.

Both shells are dewaxed, by rapid heating in a flame.

The shell cup, containing enough metal to fill the mould cavity, and a lump of carbon, is glued with ceramic paste to the mould.

An insulating, but microwave transparent, ceramic fibre block is placed around the cup area of the mould.

The assembly is placed in the oven chamber, and the timer set for a specified time. The firing time depends on the type and mass of metal to be melted e.g. 330g of sterling silver would need 17 minutes in an 850 watt microwave.

When the beeper sounds, the mould together with the insulation, is removed from the chamber and inverted, allowing the metal to run into the casting cavity without loss of temperature.

When the mould has cooled, the shell is removed to reveal the casting.

I dunno. I just can't see it.

You gotta love the request for $30, for a pamphlet.

[Caeberos]

wasn't that in last month's popular science?

[sevisehda]

Yes.

[bigben2k]

Ok, so can you explain it to us? In plain english?

[RoboTech]

Originally posted by bigben2k
Ok, so can you explain it to us? In plain english?

Well, as I understand the concept... you take a material that absorbs microwaves and heats up in the process (susceptor) like silicon carbide or a graphite/magnetite mix. You then use these materials to form either a heated surface - hot block, which you can set at crucible on OR make a casting out of the material to both heat and form the material being melted/cast.

No, I haven't tried it... (yet)...

Popular Science, Sept. 2003, pg. 102

[]JR[]

Whats wrong with using the charcoal bbq/flower pot method for melting metal?

Hunks of copper in a microwave dont sound too good for you or your neighbours health.

*reading article now*

]JR[

[Cossey3]

dont metals absorb microwaves themselves, cause if you put something like wire wool in a microwave it rapids glows red then white then melts to form a smal puddle of steel. so you should just be able to use a crucible filled with the metal.

[MadHacker]

Originally posted by Cossey3
dont metals absorb microwaves themselves, cause if you put something like wire wool in a microwave it rapids glows red then white then melts to form a smal puddle of steel. so you should just be able to use a crucible filled with the metal.

without propper insulation you will get a lot of sparks...

try this... put a CD in a microwave and set it for 3 seconds..
and watch the sparks fly.. but for only a moment...

this i have done myself..(every time a burn a coaster)
but without proper insulation you will get a lot of sparks...
anybody ever put a key in a microwave?
i havn't.... yet...

[Cossey3]

ever tried sticking a metal cup full of glacial alcohol in one a couple of seconds of sparks then the microwave explodes. (dont try this at home kids!!!)

back on subject
if you where to use an almost inclosed crucible that was insulated would it work? might have a go at the weekend ive got an old microwave lying about.

[pakman]

while your at it, I'll donate my neighbor's cat to toss in the microwave...