Instructables

Step 5: Prepare metal and crucible

Picture of prepare metal and crucible
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I used a stainless steel measuring cup for my crucible, which has a meting point of 1510°C (2750°F)
 I knew that I was only going to reach about 400/900, so using this as my crucible was a fine choice. Glass would have also worked, as it melts at around the same point as stainless steel (and higher, depending on the type of glass).

Find your metals and coil or snip into your crucible.
 
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AKA the A3 years ago
Not only does the grass soften as you heat it, but when it reaches the "barely visible red hot" temperature, it becomes conductive and starts to absorb microwaves (and thus heats up even more)...
butterknife3 years ago
Using glass would not generally be a great idea. While glass doesn't liquify until around 1000ºF, it does weaken significantly at temperatures as low as 300ºF, and it can lose surface tension around 800ºF depending on the glass. Borosilicate and tempered soda-lime glasses stand up to heat much better, but I really wouldn't advise it. The potential for harm is just too great. Sudden temperature changes from hot to cold can cause microscopic stress fractures in glass as well, which will eventually lead to breakage or shattering.

Stick to stainless steel or ceramic crucibles for anything more intense than Bunsen burners or conventional ovens.