Tubes are shy creatures that prefer an enclosed life.

[DougH]

Well, I'm sure there's more to the "heat" issue than just how much current they pull- that was just the first thing I thought about. Size of the envelope, materials used, thickness of the envelope maybe? I'd guess there are a lot of factors that come into play.

[SonicVI]

You needs a roll bar on both sides of the tube methinks.

[drk]

thanks 

[petemoore]

I'd guess there are a lot of factors that come into play.
  Effeciency of the heater element, size of the tube.
  I got a tube socket that accepted nicely a little 1/8 machine screw, [this socket has a hole through the middle. the thinly cut threads [using the screw] seemed more than sufficient going through more than a 1/2'' of socket body material.
  Long machine screw through: Rubber washer, washer, perfboard, 1/4''wide x 1/4''tall insulated tube [ballpen casing], into the sockets threads.
  That puts the tube socket on a 'shock absorber' mount, and uses the circuit board to place the tube in the enclosure.
  A slotted aluminum strip, salvaged from inside a monitor, 2''w, long...[like 8 inches?], was easy to bend because of the slots that had been stamped in it, goes all the way over the tube, only 2 sides left open, enough open 'angle' to allow positioning the eyes to view the glass, providing 'better protection.
  Start with a plate of metal like:
             l   
  -----------------------------------
                              l
 
  form the center length of the strip laid flat into a 'U' shape. The strip/template must be long enough to span over the tube and have tab ends for screw mounting into a boxtop, after bending the 'l' tabs to form side guards for the tubes new 'wrap-around U' tube guard. 
  In the case of a tube socket near a side, make a lopsided 'U' guard and use the side to fasten the longer tip of the U.
  You can use self tapping screws to mount the guard to the substrate[s.
  ~Easy trick except the metal working, unless your'e into metalurgy.