Blaupunkt Barcelona 2340 - Radio 1956/57.

[rsjsouza]

Go old school and have your way with parafin wax...

Seriously, though, I tend to use something I can remove at a later time (in case of future repairs needed), ruling out something aggressive as cyanoacrilate or even silicone (it heats while curing). I also try to avoid Gorilla epoxy (the one where you mix the two tubes) as I never know if the heavy smell may be indicative of a slow (and possibly destructive/corrosive) chemical release over the years.

There is a glue that I tend to use quite often for general purpose and it seems relatively mild: E6000. It cures as a somewhat flexible joint and, in this particular case, it would keep the ferrite (a very brittle material) somewhat protected from mechanical stresses as the glue would dampen any torsion/vibration.

[TimFox]

Magic eye tubes again:
A great encyclopedic reference to vacuum tubes from US, GB, Europe, and the USSR is the “Electronic Universal Vade-Mecum”, originally published in several editions by the Polish publisher Wydawnictwa Naukowa-Techniczne of Warsaw, during the Communist government.
The chapter “M” covers magic-eye tubes.  To show function, the figure shows a slide-rule dial on a receiver, where “Geneve” is being tuned, ignoring “Warszawa” and “Mockba” (in Cyrillic) nearby, and the corresponding shapes on different models of eye tube for three locations of the tuning dial.