Steel vacuum chamber thickness

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Matthew_Melass
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Steel vacuum chamber thickness

Post by Matthew_Melass »

So I'm making an arc furnace capable of melting steel. I plan to use it to mold a vacuum chamber. It's easy and I think it should work. I was wondering how thick I should make the chamber. Here's a guide to making the furnace:
https://m.youtube.com/watch?v=VTzKIs19eZE
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Rich Feldman
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Re: Steel vacuum chamber thickness

Post by Rich Feldman »

Let's start with your question. You could have found the answer by reading in fusor.net FAQs and other posts, using the search tools. People have done fusion in salad bowls and beer kegs. In the popular 6 inch stainless-steel hemispheres, 1/16 inch walls would be more than thick enough. But you will never successfully cast steel (or, I bet, even zinc) that thin at home. I just learned that high-tech investment casting can produce steel sections that thin: https://www.sfsa.org/sfsa/pubs/hbk/s1.pdf

Now let's take a higher level view. Casting any metal, much less steel, will be a very hard and expensive way to get a vacuum chamber, by the time you finish one that works. Do you want to spend a few years learning how to make and run a fusor, or a foundry?

I bet the maker of your linked video never cast metal into any shape more complicated than a cupcake. It's hard to believe that one could melt a useful amount of anything more refractory than zinc under an arc between carbon rods from dry cells, powered by rewound MOT's,
in a hollowed-out firebrick. The fact that it's referred to as a "reaction chamber" supports the idea that the video is for attracting viewers rather than teaching them practical methods.

When I started pouring aluminum & brass in my backyard 30 years ago, I thought the challenging part would be getting a pot full of molten metal. Nope. Before you can make anything useful, you need patterns and molds. The materials, tools, and skills for that make the metal-melting part seem easy.

Good high vacuum chambers can be cast, even in aluminum, as Andrew Seltzman pointed out last year with reference to a plasma physics facility at U. of Wisconsin: viewtopic.php?f=6&t=9271&p=64334. It's not easy or inexpensive. Here are some pictures from the "news" link in Andrew's post, showing mold assembly and pouring at Portage Casting and Mold Inc.
dynamo_pour11_0705-sm.jpg
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dynamo_pour_remote11_1080-sm.jpg (62.8 KiB) Viewed 5476 times
All models are wrong; some models are useful. -- George Box
Jerry Biehler
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Re: Steel vacuum chamber thickness

Post by Jerry Biehler »

Rich is right, there is no way in hell you are going to be able to melt enough steel with a setup like that to cast something like a vacuum chamber, especially out of steel. And in reality, steel is not what you want, you want stainless, and that is usually melted in vacuum furnaces.

That guy that has the youtube channel has some neat toys but a lot of what he does is half assed and dangerous. His video on casting aluminum was terrible. It was full of major issues.

Handling molten steel is anything but easy.

I have seen small induction furnaces that would do what you need but they run into the hundreds of kilowatts, way more power than what the feeders to your house can handle.
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Dennis P Brown
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Re: Steel vacuum chamber thickness

Post by Dennis P Brown »

Agree with those here. I had a furnace that could easily melt steel (and I melted very high temp glasses a 100 C above steel's MP.) When I opened the furnace door - anything at all flammable within three feet burst into flame. I wore very special heat reflective cloths/arm covers/gloves/full face shield with welding mask and still, it was very bad and I could endure it for only brief seconds. This unit had about one cubic foot volume. To handle a large amount of molten steel would be extremely dangerous - learn to weld and buy the components! Easier and far, far safer.
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Richard Hull
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Re: Steel vacuum chamber thickness

Post by Richard Hull »

A small correction to above. To my knowledge no one has ever done fusion in a beer keg or a salad bowl. Such folks rarely pack the gear needed to do fusion. What is correct is that some folks have actually made a non-fusing, "demo fusor" using salad bowls and a beer keg. Serious fusioneers on a restricted budget looking do actually do nuclear fusion and win, have used
re-purposed, stainless steel vacuum couplings, cylinders, Tees, crosses, and spheres. These have been purchased surplus, for the most part. Aluminum would be acceptable, but I am unaware, correct me if I am wrong, of any person admitted into the fusioneer listing using a chamber of pure steel, brass, bronze, copper or aluminum.

Naturally, anyone is welcomed to try cast steel, cast silver or gold or hand hammered or spun ruthenium, niobuim, thullium or any other metal. The true, easy-path, winners choose only stainless steel.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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