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Re: Ovens.
At 08:03 PM 3/26/1996 -0500, EclectiKat@aol.com wrote:
>All you do is heat the glass just up to the point where the orange
>sodium flame just starts to come up, and go over it until the vacuum drops
>again, while induction heating the electrodes. You continuously pump on the
>tube, so you get out more of the impurities, and you can monitor the
progress
>of the bombarding process by watching your vacuum gauge go up initially,
then
>down to base pressure again as the outgass products get depleted.
Al Hooten wrote:
How do you make sure the underside of the unit is heated, Jeff?
Is the unit supported on a rack of glass tubes (as in traditional
bombarding), high enough that you can get the torch underneath? Or
is this not an issue because the glass transmits the heat well enough
by itself?
Reply:
As I indicated, I support the tube on tiles or bricks, which I have on my
table as a sort of "set of blocks" to move about on the surface as needed for
each tube shape.
Another question: I don't understand when you heat your
electrodes via the induction heater... before, during, or after
the time you're heating the glass with your bushy torch?
Reply: usually start heating the electrodes until the vacuum drops back, then
keep it on while I heat up the glass, which raises the vacuum level again for
a while until the combination drops back to base pressure. This way I can
separate the effects of the glass from the electrodes and observe each
process independently. Also, find that the electrodes will re-absorb some of
the glass out-products unless I keep them hot or re-heat them, so requires I
keep processing them.
Jeff