[AMRadio] 813 question

Todd, KA1KAQ ka1kaq at gmail.com
Tue Jan 31 13:37:47 EST 2006

I haven't heard of this either. How would using them now suddenly
prevent the adhesive from continuing to go bad, if it was really an

I suspect perhaps the reference is more in line with the big transmit
tubes that sit around and either get gassy from sitting or have
brittle filaments due to the metal composition. There are many
references to these events happening, even with more recent tubes with
respect to becoming gassy, and the recommendation to 'burn in' tubes
that have been sitting inactive for any long period of time.

Although I should add, the reason I heard for becoming gassy over time
was due to molecules being released from the materials used within the
tube itself moreso than leaking past pin seals.

813s seem to be the one large transmitting tube I have in excess as
well, and none of them appear to have loose bases, whether used or

de Todd/'Boomer'  KA1KAQ

On 1/31/06, ronnie.hull <ronnie.hull at glowbugs.com> wrote:
> I have certainly never heard of that, but I'm no expert. However, I have a box
> full of 813's that are ww2 vintage and NONE of them have loose bases.

> > I have a buddy who insists that if I don't get my old
> > 813's out of the "future project" box and fire the
> > filaments up on them now and then, the base seals will
> > eventually deteriorate.  I guess he is talking about
> > the adhesive that secures the base to the bulb.  I
> > don't see how the glass envelope where the leads pass
> > through the glass could be affected by lack of use,
> > but maybe one of you folks has experience with this.
> > Anybody heard of this one before?

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