Re: [ATM] Microwave heating of glass

["Ashley Roll" <ash@digitalnemesis.com>]

Hi Everyone, 

I'm a lurker on the list and have been for quite some time, but I think I can add to this discussion.

I work in the mobile (cell) phone industry and the company I work for designs equipment that works at these kinds of frequencies. Microwave ovens are generally about 2450MHz (2.45GHz).

I want to add a little bit of a safety warning here:

Basically at the power levels in the oven you really don't want to be exposed to the RF power. The doors and windows are carefully designed to limit the amount of leakage energy, but I would be concerned with thermal issues if you start trying to melt glass inside. The temperature is going to be way higher than anything the oven was designed for and I expect that the casing would warp, potentially causing the RF sealing to fail and power to leak out.

In theory you could build a custom enclosure and bolt one or more magnetrons to it to make a microwave kiln, but that is really a lot of effort and the RF power you are talking about is quite dangerous. It is also not a simple matter to efficiently couple the magnetrons to the chamber. You would also want to determine how efficiently the microwaves actually heat the glass, but I'm not entirely sure how to go about that. Perhaps measure the heat difference after a certain length of exposure and calculate the energy used verses the energy added to the glass.


As an alternative, perhaps something along the lines of an induction heater would work? I'm not sure that this will work, but if it hot glass can absorb microwaves, it can probably be melted with an induction furnace. These things are used for all sorts of industrial processes and are quite efficient. They are used from steel making to growing silicon crystals for electronics.

Cheers,
Ash. 






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