Wood/Glass/Metal Seeking a cheap wide mouthed jar capable of withstanding a vacuum

[Ducatidragon916]

I used a cookie jar purchased from target. I used progressive grades of sandpaper and water and ground the lip of the jar using circular orbiting motions on the sandpaper to even out the surface so to establish a tight seal for a good vacuum. The photo shows the setup I am still working on to do Vacuum deposition experiments etc. When I am ready I will build a protective screen shroud around the glass in case of implosion protection. Will be interesting to see how much vacuum a glass cookie jar can withstand.
The images show the lip of the jar with a 1/4inch surface ground flat and the overall size over the nickel plated steel plate. Height of the jar is about 10 1/2inches and the diameter is about 9 inches in diameter.

 

[Tom.G]

STRONG RECOMMENDATION:

BUY A BELL JAR!

 

[Baluncore]

When I am ready I will build a protective screen shroud around the glass in case of implosion protection. Will be interesting to see how much vacuum a glass cookie jar can withstand.

A glass jar will be structurally stronger under a positive external pressure, than it is under internal positive pressure. An internal vacuum is equivalent to an external positive pressure, and is limited to atmospheric pressure of about 14.7 psi.

A normal vacuum is as dangerous as a high vacuum, the high vacuum just has less contamination.

The danger of a vacuum is primarily for things inside the chamber, things that will be cut or crushed, by the imploding walls, or the incoming atmosphere.

The external danger of an internal vacuum is the projectile fragments that accelerate through the container, bounce off the contents, or pass through the opposite wall. One lethal example is the electron-gun in the neck of a cathode ray tube, that was aimed at the operator's head, who was watching the screen.

 

[sophiecentaur]

STRONG RECOMMENDATION:

BUY A BELL JAR!

But not just any old bell jar!!!! A Google search produces many bell shaped display jars : not what you want. They are just a few quid. I couldn't find anything sold as a vacuum jar for less than £100. There may well be polycarbonate jars that would be strong enough and not lethal. Small is cheaper of course but if you want to do experiments then one that's too small soon becomes useless for you.

 

[Nik_2213]

Again, may I mention the stretchy plastic safety mesh which we used on eg rotary evaporators ??

Yes, yes, have a safety enclosure too, to be sure, to be sure...

 

[berkeman]

Okie dokie, this thread is now closed again for good. To anybody reading this thread in the future, it's best to buy a purpose-built Bell jar as mentioned early in this thread, and the latest suggestion by Ducati to build a safety enclosure is good as well. (I've used 1" think Lexan at work in the past)

Thread reopened provisionally.

Welcome to the PF, Jon.

We just need to be careful not to allow dangerous discussions here at the PF. We'll see how this discussion goes, and hopefully you can get some good suggestions. Whatever you end up with, it will be important to have a protective barrier around the jar to contain any implosion/explosion fragments if there is a problem. I (unfortunately) have some experience with an exploding glass jar, and it was just pure luck that my roommate and I were not in front of the jar when it exploded.

And even though you are on a budget, for less than $120 you could get a standard Bell Jar that would probably be a lot safer for your experiments...

https://www.zoro.com/sp-scienceware...MI9b-rsrDi2gIVA9bACh2T9A-9EAQYAiABEgJODvD_BwE

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