[Collins] Broken plate cap

[Bill Abate]

One of my 811A's in my 30L-1 had its plate cap separated from the wire. 
  I was able to resolder the plate cap to the wire.  I used 2% silver 
solder as I thought that would be a little better.  But now I have to 
secure the plate cap to the glass envelope.  I thought about using epoxy 
or Monster glue but most glues and epoxies soften with heat.

Anybody have experience with this problem?  Strangely the tube is still 
good!  Operating a triode with full drive but without plate voltage 
should have destroyed it.  At least I think so but obviously I am wrong.

73,

Bill, K3PGB