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Thread: Plasma Globes

  1. #11
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    @Steve,

    Would something like this be easier? Just a glass tube with some electrodes?

    http://strattman.com/lightning_tube

  2. #12
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    Straight tubes are infinitely easier. I can use stock electrodes with them and easily bake them in a tube oven.

    Dalibor's videos make it look easy... Merely getting the materials costs a fortune. It took me years of searching for sources of the three special glasses with controlled expansions that you need to get from a nickel/iron metal rod to Pyrex. The stuff retails at 200-300$ per pound of glass, minimum order of one pound of each type.

    Leaded glass appears easier for glass to metal seals, but it also is far easier to break and does not like high temperatures, like bakeout sessions. When you use it, it can turn black and liberate free lead at sealing temperatures unless you are very careful. Dalibar went out of his way to get the right custom materials for a leaded glass stem seal. He considers the material sources a trade secret, and rightly so. It probably was far easier in the FSU/Eastern Europe to do so then in the US.


    Steve
    Last edited by mixedgas; 12-07-2018 at 11:30.
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  3. #13
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    Quote Originally Posted by mixedgas View Post
    Straight tubes are infinitely easier. I can use stock electrodes with them and easily bake them in a tube oven.
    Even better. I will contact you around the beginning of the year to discuss tube length, color (based on what gasses you have on-hand), recommended HV drivers (if you know of any), and of course pricing.

    Dalibor's videos make it look easy... Merely getting the materials costs a fortune. It took me years of searching for sources of the three special glasses with controlled expansions that you need to get from a nickel/iron metal rod to Pyrex. The stuff retails at 200-300$ per pound of glass, minimum order of one pound of each type.

    Leaded glass appears easier for glass to metal seals, but it also is far easier to break and does not like high temperatures, like bakeout sessions. When you use it, it can turn black and liberate free lead at sealing temperatures unless you are very careful. Dalibar went out of his way to get the right custom materials for a leaded glass stem seal. He considers the material sources a trade secret, and rightly so. It probably was far easier in the FSU/Eastern Europe to do so then in the US.
    I have found that the more casual a person is about doing a complex task, especially one that takes finesse, no more difficult it is. You can tell Dalibor has honed and perfected his craft. This is not even mentioning how long it probably took him to source his materials. Even more so when confirmed by you, who has been in the business for a very long time.

    Anyway, thanks again, Steve. This is no-rush so, if your projects have you backed up, please don't make this any kind of priority.

  4. #14
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    Steve I have access to 20 lbs of pure xenon...yes you read the units right.

  5. #15
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    Quote Originally Posted by kecked View Post
    Steve I have access to 20 lbs of pure xenon...yes you read the units right.
    That's a lot of Xenon... About $22,000 worth if the numbers I have are right!

  6. #16
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    He's not going to be too happy if he remembers me. I'm the one who tossed the box in the trash for a seal destined for THAT lab. We received an unmarked box from a vacuum suppler in Dr. X's lab. I Opened the box, tossed the seal in the drawer...Assumed it was for us. I tossed the box. Next day he's at our lab with grad students in tow, tearing every drawer and piece of gear apart looking for HIS little seal with all the force of a search warrant. If I recall correctly he was bleeding off quite a bit of gas that day. Not one of my better days. NEVER ASS SUME anything at a University. I was the ass in this case. Shipping and receiving some how decided everything like Duniway was for X's lab that day.

    I have a way of getting slightly impure xenon into the vacuum system, already. You pinch seal a flashtube into a copper tube and break it using the crush tool for a Coherent laser refill capsule. . Not the purest stuff, but not bad. On average flashlamps have 400-750 torr of Xenon in them.

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  7. #17
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    Quote Originally Posted by mixedgas View Post
    I have a way of getting slightly impure xenon into the vacuum system, already. You pinch seal a flashtube into a copper tube and break it using the crush tool for a Coherent laser refill capsule. . Not the purest stuff, but not bad. On average flashlamps have 400-750 torr of Xenon in them.

    Steve

    Interesting. I have a couple of big 9.5" xenon tubes from Electronic Goldmine. https://www.goldmine-elec-products.c...?number=G19044. Curious how well that would work.

  8. #18
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    Quote Originally Posted by mixedgas View Post
    You pinch seal a flashtube into a copper tube and break it using the crush tool for a Coherent laser refill capsule. . Not the purest stuff, but not bad. On average flashlamps have 400-750 torr of Xenon in them.

    Steve
    Neat! Thanks for sharing that tip, Steve! I'm definitely going to try this out next time I make a glow discharge tube!

  9. #19
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    Quote Originally Posted by CountFunkula View Post
    Neat! Thanks for sharing that tip, Steve! I'm definitely going to try this out next time I make a glow discharge tube!
    Many of those smaller tubes are sealed by stacking them in a chamber backfilled with Xenon, then dropping on a previously beaded electrode, and sealing the glass around one electrode with an IR laser or by placing a graphite cap on them and induction heating one end. So I cannot vouch for the purity of the xenon from any outgassing products.

    I'm not sure how well small strobe tubes get factory processed in general. The pressures are fairly to very high, so who cares once you activate the electrodes. Laser and Medical lamps DO get processed however.

    If you can't see a "tip-off" tube on the glass you may assume they are machine made and sealed by the "drop on the beaded electrode and melt" method. Reed relays that have deep green glass are a giveaway, they are designed to adsorb ND:YAG or CO2 light for laser sealing.

    Steve
    Last edited by mixedgas; 12-20-2018 at 12:19.
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