[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Large Plsma Tube



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" <teslas-intern@xxxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
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





_________________________________________________________________
Your smile counts. The more smiles you share, the more we donate. Join in.
www.windowslive.com/smile?ocid=TXT_TAGLM_Wave2_oprsmilewlhmtagline_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla