Same! First learned of these maybe one year ago. Need a spare microwave for experiments…
xattt 15 hours ago [-]
I’m trying to understand how the magnetron doesn’t burn out. I am assuming 100% efficiency for microwave absorption?
DoctorOetker 1 hours ago [-]
As long as there is a good resistive microwave absorber in or on the inside of the kiln, and as long as the kiln insulating properties suffice, why would the magnetron burn out?
dlcarrier 10 hours ago [-]
I don't know what you mean by 100% efficiency.
The magnetron burns out from a high standing wave ratio, which is the ratio of how much energy bounces back into it, to how much its outputting. If you aren't heating anything up, the microwaves bounce back and cause damage.
If you have something in the oven that absorbs the microwaves and gets hot, then you're fine. Liquid water does this, including the water in your food, but ceramics do it too. That is why when you cook frozen foods on a ceramic plate, the plate can heat up faster than your food. Once the food defrosts, it'll have liquid water and begin cooking at full speed. Sometimes the food only defrosts from the plate heating up, so you end up with food cooking from the bottom up, instead of the top down.
xattt 3 hours ago [-]
This is what I meant: does the ceramic crucible absorb energy as efficiently as water… or is the magnetron considered disposable in this case?
According to the other comment, it is indeed disposable.
DoctorOetker 58 minutes ago [-]
I don't think eugenekay's reply is helpful, unless in the pedantic sense:
yes every microwave oven eventually fails.
yes it is good practice to dedicate a microwave for food and a microwave for science experiments.
eugenekay 14 hours ago [-]
It does, eventually. For this type of project don’t use a microwave that you plan on ever using for food - or anything else - ever again.
jacquesm 13 hours ago [-]
Very impressive, I really liked how low tech it all was (except for buying a high purity Si wafer but I can see why growing a crystal that size wasn't on the agenda). Nice to mention Jeri, that first 'cooking with Jeri' episode probably ranks as the all-time-high for makers in my book.
oliculipolicula 12 hours ago [-]
I'm semithrilled to learn that TEOS is hotseller on eBay.. (BC intrusive thoughts of inhaling glass)
Same reaction to purportedly sub-$30/300degC homemade solar cells (BC lead poisoning)
inclusive of equipment
Perovskite Solar Cell: Build a Working One at Home
Anyway, very cool home project.
The magnetron burns out from a high standing wave ratio, which is the ratio of how much energy bounces back into it, to how much its outputting. If you aren't heating anything up, the microwaves bounce back and cause damage.
If you have something in the oven that absorbs the microwaves and gets hot, then you're fine. Liquid water does this, including the water in your food, but ceramics do it too. That is why when you cook frozen foods on a ceramic plate, the plate can heat up faster than your food. Once the food defrosts, it'll have liquid water and begin cooking at full speed. Sometimes the food only defrosts from the plate heating up, so you end up with food cooking from the bottom up, instead of the top down.
According to the other comment, it is indeed disposable.
yes every microwave oven eventually fails.
yes it is good practice to dedicate a microwave for food and a microwave for science experiments.
Same reaction to purportedly sub-$30/300degC homemade solar cells (BC lead poisoning) inclusive of equipment
Perovskite Solar Cell: Build a Working One at Home
https://youtu.be/3ghatCS0_HY <-- another PhD
https://pubs.rsc.org/ta/article-abstract/5/37/19972/587815/H...
(Somewhat more expensive, though more edible ingredients)
https://www.semiconductor.diy/guides/microwave-solar-panels/