Am I remembering the color wrong, or was it green? I've been thinking of green a lot because I'll be modding a green light for my kid cousin. Or do I have it all mixed up now? If I learn to anodize, then I'll have many more options.
When I asked my chemist sister about a vacuum chamber for this purpose last week, she basically said that buying it would cost a million dollars, making it would probably result in death when it implodes, and a hvac vacuum pump would take at least days before it got down to a suitable pressure, but it probably could get to a low enough pressure if given enough time. She's not big into electrochemistry though, so she said she'd try to get some better answers from people that were into it.
It can be! Also milled. But you don’t cut it… it’s more of a grinding process.
I know a guy that developed a process for milling silicon carbide to insane tolerances. They were using silicon carbide blanks that were made by a CVD process… a 6 inch diam blank cost around 250 grand… you don’t want to scrap too many of those.
You had the right color. As far as the vacuum chamber, atmospheric pressure is all it has to hold out. 14.7 psi isn't very challenging. So the chamber is almost trivial. I'm not sure why your sister thinks it's a big deal. There are people out there pulling 13.7 psi (27"Hg) vacuum using glass cake pan covers and pyrex bowls... I would build my chamber with some nice thick aluminum.
This guy is a hack, but you get the idea. He's using a 2 stage vacuum pump which should be able to pull below .002 psi.
I can't currently find the video of a guy who actually used the glass cake cover. Still looking.
The only high cost item in this build would be the pump if indeed 4 or 5 micron vacuum is required.
There are people who can design a Hadron Collider and there are people who can utillise a Hadron Collider, and then there are those who can build a Hadron Collider.
It’s only 14.7 PSI, but multiply that by a lot of square inches and it adds up quickly. Believe me, you don’t want to be around when the dome implodes. Even a tiny flaw in the material and it’s all over… I use a 1+” thick lexan sheet to cover the mixing bowl I use to de-gas rocket propellent. Acrylic is known to not survive (and that is at only around 26” of vacuum over a 12” diam bowl.
Another video. Glass domes seem to be the standard for experimental vapor deposition. I see no problem with this. Glass is pretty strong in compression and the dome shape keeps the glass in compression along the entire surface. Surface defects should be inspected for, but generally speaking once a piece of glass is made and inspected it won't gain defects barring being dropped or dinged which usually results in total breakage anyway.
