Richard wrote:
  Well, the previous discussions along this line talked
about removing
 the laminated front with a nichrome wire.  I believe at least one list
 member reported using this technique. 
I did it with an HP-250, but that was for a non-functional system (i.e. it
needed to look as nice as possible, but increased implosion risk was not a
factor) - hence there's currently just an air gap between CRT and faceplate on
that particular machine. For that tiny screen, I got enough juice (just) from
a plain old PC power supply to cut through the failed sealant.
(One day that machine almost certainly will get restored to working order, but
not in the near future I suspect)
  Maybe there's an easy way to keep the thickenss
uniform and then you can
 repair the safety as well as the appearance. 
Personally I've used a lot of 70s and later machines and never known a tube
implode - I think for my own use I'd be tempted not to screw around with
replacing the sealant (subject to next owner knowing what they were getting,
of course). I wouldn't want to risk it for anything "public" though.
cheers
Jules