I did consider it. After having all my firebricks melt, I started thinking about ways to protect the brick. The best I could think of was to coat the top of the furnace, and the bottom of the lid with the same stuff the crucible was made out of, but that's a bit beyond my ability. There definitely were hot spots. I spent a lot of time moving the samples around just trying to get them to heat up at all. For that, maybe we could change the shape of the microwave oven. Instead of a box, we could make it a thin-ish (2-4 inch diameter) cylinder that is about the wavelength of the microwaves. That way the hot spot would be more reliably and understandably located.

@@FreedomOfDegree Yeah, I've always wondered about that as well. Can you modify the shape of a microwave to focus all the energy in one spot. It's fun trying to come up with ways to do that. A standing wave in a tube sounds like a good way to go. However, I wouldn't dare open up a microwave, modify how the radiowaves travel, and be anywhere near that thing when it turns on 😅 Even if I do think I grasp most of the physics behind it, and you can make a fine metal mesh all around it (like the one usually in the door behind the glass), and still I would feel like I was forgetting something 😛 To find the hotspots, I've seen people using things like chocolate sprinkles on a plate and see some places melt and others untouched, but that's just one 2d slice. I always wondered if you put a big block of styrofoam in it filling the chamber, if all the hot spots would melt so you can see them. Not sure styrofoam heats up though. Or else a giant block of cheese :D Oh and you have to slice it up after to explore the inside of the block otherwise you can't see where it melted.

@@FreedomOfDegree I found another interesting thing on wikipedia.org/wiki/Melting_point : "Melting points are often used to characterize organic and inorganic compounds and to ascertain their purity. The melting point of a pure substance is always higher and has a smaller range than the melting point of an impure substance or, more generally, of mixtures. The higher the quantity of other components, the lower the melting point and the broader will be the melting point range, often referred to as the "pasty range"." I wonder how much the melting point shifts with impurity. Assuming store bought glass is more pure than your own mixture, can you just use a jam jar, and have your powdermix melt before the jar melts? It might be less sticky on the glass surface, and you can see what happens while trying it.

@@FreedomOfDegree You can locate the hotspots with a bag of shredded cheese. They're 3D regions, though, so lock in the right height and mark the oven. Google 'measuring speed of light with microwave', it's a popular demonstration- cheese, chocolate, hotdogs, to name a few I've seen. I don't think modifying the oven is the way to go here- It's exciting/interesting, but it's also a distraction. Even if it weren't dangerous (and omg it is and absolutely will kill you if you let it), there's still plenty of science to explore here before going off to wherever a custom oven takes you. In the interest of prototyping/exploring the properties of your set up, try smashing good reclaimed glass (empty salsa jar, spent beers) and melting it down. Do one experiment at a time; Get your brick/crucible/oven situation sorted so that you're confident in your procedure for getting flowing glass, then start fooling around with ingredients. I know it's not as click baity to do them separately, but you can combine them in the edit, and the reclaimed glass will make great B-roll.

I don't think microwaves are that scary. @mrgreenguy did a really good video on the subject: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-3hBRxwQXmCQ.html I also think the "shotgun method" can be valuable when doing science, especially when you are fairly certain that the multiple variables that you changed are not likely to interfere with each other. For instance, the last run I did, I used a much larger amount of silica in the mixture. I expected it to make the liquid glass less runny. I also threw in the steel security screws. I did not expect them to mix with the glass. In the end, the glass was much less runny, and took on a very pretty green color. While I can't say for sure that the additional silica is the reason it was much thicker because I added the screws, I have very good reason to believe that that is the case, because I think it's unlikely the screws had such an effect on the mixture.

Thanks! There definitely were unknown fumes when I heated the sand from the stream. I don't think the boric acid or the sodium bicarbonate would give off too much. Maybe some CO2 or water. They might have been vaporizing as well but I feel it was well ventilated enough for those.

That's a good point. I think so as it seemed to be firing. It audibly changes sound at some point and I think that's when it stops getting spark. It also got warm to the touch and I don't think friction and compression alone could get it that warm.

I put on the glasses.

That might destroy everything.

I'll look into them. But directly heating the glass feels like it heats up faster and maybe even hotter. The main way I thought I could improve my design was to cover all the fire bricks with a layer of the same stuff the crucibles were made of (quartz ceramic I think). But I'm not sure if the fire bricks might spontaneously catalytically melt at such high temperatures.

​@@FreedomOfDegreeI will subscribe to see how you go :)

I did experiment a little with silicon carbide powder. I was hoping that I could add it directly to the mixture and it would heat up enough that I wouldn't have to pre heat it with the torch. I could never get the silicon carbide hot enough on its own. I didn't know microwave kilns were a thing, that's pretty cool.

Corn starch is the most flavorless one I know.

Was considering it. Realized after that copper probably does some silly stuff when electrocuted. Iron is probably better considering you need it in your diet anyhow.

😘

My cousin had a handmade one (he didn't make it though) made of like 2x4s and nails that worked just like that. I wanted to try and push it further. I felt the sideways design might have been able to increase the cook rate, but I guess there's more to it than I thought.

Was at 3 now at 7 subscribers, to the mooooon