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Re: [TCML] Large Plsma Tube
Scott,
You jogged my memory, it was Hysol C1, low out gassing epoxy. You
are also correct that the data sheet has nothing about vacuum
applications. It supposedly works very well however, and was tested by
the table top fusor people to about 10^-6 Torr and reccommended as a
cheap alternative to torr seal (I cannot support this claim as I lack
the equipment) either way, that is way more vacuum than my pump can ever
get, so I should be good. Thanks to the webpage link, it is very
informative.
Scott Bogard.
huil888 wrote:
> Scott B. -
>
> Loctite "Hysol 9492" claims to be a "low outgassing" two-part epoxy
> adhesive, but the technical datasheets don't provide any specific data
> to support this. It's likely that this material is not really suitable
> for vacuum applications, at least not for anything other than casual
> experimentation. The "low outgassing" claim is may be valid for
> ambient-pressure applications mounting optics, etc where the adhesive
> won't outgas sufficiently during curing to leave a deposit on nearby
> surfaces.
>
> There is some interesting data on this site for high-vacuum leak
> sealants:
>
> http://www.2spi.com/catalog/vac/weight.html
>
> that shows the relative outgassing rates for silicone RTV sealants and
> potting compounds, various epoxy resins, Nylon, Delrin, polyolefin
> wire insulation, etc.
>
> Watch the scale factor for the weight-loss axes, as it varies from
> chart to chart.
>
> Regards,
> Scott Hanson
> ----- Original Message ----- From: "Scott Bogard"
>
> To:
> Sent: Thursday, November 29, 2007 9:13 AM
> Subject: Re: [TCML] Large Plsma Tube
>
>
>
> David
> I don't know too much about gas conductivities, but I think the
> other two cents I have may be of use to you. Neon has the lowest
> conductivity of any pure gas, and produces a red color discharge. I
> believe Argon is next, and that makes a purple or even orangish or blue
> discharge dependent on pressure. You are going to need a pretty hefty
> power supply for a tube of that size, I would not recommend DC, as it
> may slowly damage the tube walls because of ion migration, and depending
> on your setup, I may not make much light. I think for a tube so large a
> fly back transformer just won't cut it, I am sure your TC would do the
> job quite nicely, but the display will be loud and very frantic (and
> probably painful to touch). Some problems you may run into involve
> evacuating the tube, filling with gas, and then sealing it. You should
> not use any plastic as it may allow air molecules to leak through, only
> metal or glass. Most epoxies will outgas and spoil the discharge, but
> after searching the net for a few years I've found one that doesn't, it
> is supposed to be good to 10^-6 torr, and the table top fusor people use
> it, so it should be good but I have not yet tested it (I cannot remember
> what it is called, only that it is made by Loctite, and it is sold as a
> general purpose epoxy. I will check the box when I go home tomorrow and
> send the information to you). Do not bother with silicone, except for
> short term testing. My webpage for plasma colors should be very useful
> to you, it shows lots of pictures of whats out there as far as gas
> combos and what they look like.
> http://bogard.110mb.com/Plasmaglobecolors.htm
> My other Plasma globe pages should be useful to you as well. Mark Dunn
> can tell you where to get gases. Best of luck, let us know how it goes.
>
> Scott Bogard.
>
> David N. Van Doren wrote:
>> Hello All
>>
>> I have a large glass tube 6" o.d. with .25" walls and 5 feet long. (
>> from and old blueprint machine) And it's just begging to be made in
>> to a large Plasma tube. Somewhere I saw a list of gasses and their
>> conductivities and can't seem to find it. Does any body know where it
>> might be? If any of you have any experience or info that might help
>> with this project I'd greatly appreciate the boost in the learning
>> curve.
>> I have several HV sources that I hope will be usable for this project
>> such as an 85KV x-ray transformer or an 50 KVDC power supply and of
>> course my Tesla coil ( an OBIT powered magnifier)
>> This has the potential (sic) to be a very beautiful display.
>>
>> Thanks
>> Dave
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>>
>>
>>
>
>
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