Archived - Mason Jar Fusor

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
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Mike Veldman
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Archived - Mason Jar Fusor

Post by Mike Veldman » Mon Apr 19, 2004 2:09 pm

I have archived this only because it shows how easy a demo fusor can be made. *****Warning***** This is not a great way to make a demo fusor as the mason jar is thin and of non-pyrex construction. The whole assmbly could have imploded. It is recommended that you NOT try this. The mason Jar is made for containing jelly and not high vacuums. RH


Here are some photos of an experiment using a mason jar as the vacuum chamber. The top and bottom plated are fabricated using 1/4" aluminum plate. The top plate has a groove an eighth of an inch deep and 3/16ths wide turned into it. That groove is filled with silicone rubber to make a soft seal on the jar. One of these pictures shows my vacuum demo cart which is built out of an old patio grill frame. I just changed the axel and wheels, added some square tubing and all thread, a couple of pieces of 3/4" plywood, a welch 1400 sereis pump, a little pipe and valving and instant vacuum demo cart.
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Mike Veldman
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Re: Archived - Mason Jar Fusor Addendum

Post by Mike Veldman » Fri May 21, 2004 2:01 pm

Here is the rest of the story so to speak, I probably should have included this in my initial post on this subject. Before I fabricated a demo fusor using a wide mouth quart mason jar I ran a few tests. In my experience I'd never seen a canning jar holding foodstuffs broken. Even when frozen the top would pop rather than break the jar, so I was curious what would happen under a vacuum. I bought two cases of jars and ran some break tests. Pictured below is the first of twenty jars I tested on one of our Instron machines here at the lab. We use these machines to test compression and tinsel strength of all kinds of things. I set this one up to measure pounds per square inch (PSI). Each jar has four different sides and a bottom, so I tested twenty jars. The jars were tested as you see them, lacking the lid. The average break point was 28.3 psi. The highest pressure was around 45 psi the minimum 20.3 psi. Just as a comparison, the second of the two 4" three neck pyrex boiling flasks I purchased shattered at a little more than 16 psi. An interesting note on this is that none of the mason jars shattered, just split. I know this is probably not the most ideal test, but was adequate enough for me to procede to the next step. I built the endplates to capture the jar and an expanded metal cage to surround it. In the top plate I turned a groove 1/8" deep and 3/16" wide to match the diameter of the jar mouth. This grove was filled with clear RTV and with a 1/4" rod I shaped the rubber to a miniscus throughout the entire groove. This was done to provide a soft seal on the glass, no metal surface to provide possible stress to the glass. After surviving my government sponsered senior trip to places far and strange, flat track motorcycle racing and 200mph plus drag racing in my youth I'm not about to be maimed in middle age by one of my own experiments. To gaurd against the possibility of beam heating caused breakage I rolled an expanded metal cage laced at the seam with saftey wire to match my top and bottom plates. You can see in the third photo this fully asembled. Looking at this it should be obvious why I took the cage off to post the plasma pictures.

I also do not suggest the use of any kind of glass in vacuum experiments if it's at all possible. However, if the necessary precautions are taken glass will do.

mike
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Richard Hull
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Re: Archived - Mason Jar Fusor Addendum

Post by Richard Hull » Fri May 21, 2004 2:13 pm

Thanks for adding this Mike! It really augments the original well with lots of detail and that is what newbies need to feed their lust for information on getting a system up and running. That is what makes an "Archived" post here.........Good images coupled with lots of data that not only instructs but dazzles the eyes.

Regarding breakage............It is the electron beams pinpoint heating and locally stressing small areas of the non-pyrex glass of substandard thickness that spells the end to non-vacuum rated vessels. You would be amazed at the way glass behaves when un-annealed stresses give way. Structurally, a sealed jar at atmosphere is like an egg. (strong to evenly distributed forces). This is not the case to vacuum; especially for uneven or localized extreme temperature differentials.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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