CRT implosions

[jpero at sympatico.ca]

> > Interestingly, that info implies that it's the steel strap around the 
> > perimeter of the CRT's face which does the implosion protection, and 
> 
> That strip, normally called the rimband over here, is certainly for 
> implosion protection in some CRTs. But I suspect the double faceplate is 
> part of the implosion protection too. 

Now these days, the rimband is the only part of implosion protection. 
 
> > bit at a time. Given the huge thickness of the CRT face* I would be 
> > surprised if heated wire could cause it to break (the faceplate's 
> 
> Actually, one of the easiest ways to get stresses in glass is from uneven 
> heating/cooling (but I suspect the wire you used didn't get the glass 
> itself anything like hot enough for this to be a problem).

Very easy.  Lose enough coolant in projector,  CRACK!!  I have 
personally seen 3 so far but happen in the action I have not. EXCEPT, 
I had a neck "drop off" (!!) on blue CRT in our shop displaying test 
pattern (underscan) on all CRTs.

How this could happen?

> Work out the force on the faceplate due to air pressure (which you can 
> assume is 14 pounds per square inch). It's pretty large for TV-sized CRTs!

Several tonnes even on little ones 14"-20", even MORE on 36" CRT.  
The largest CRT that was is hitachi 40" TV.

Cheers, Wizard

> -tony