CRT implosions

[Jules Richardson]

J.C. Wren wrote:
> Some useful information here: 
> http://repairfaq.ece.drexel.edu/sam/crtfaq.htm#crtcir

Rats, I almost checked there before posting too, but didn't recall any 
such section on the site!

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 the laminated faceplate is purely an additional protection against 
scratches etc. damaging the CRT itself (and therefore introducing greter 
risk of implosion)

So that article alone suggests that the faceplate isn't there to stop 
debris at all (although doubtless along with the sealant material it 
helps).

Still, it'd be nice to hear from people who've actully been involved in 
manufacturing CRTs I suppose!

I'm tempted to say that replacing the sealant material on anything past 
1970 or so is a safe thing to do - providing nobody goes dropping the 
CRT on its face, and providing that nobody tries smacking the face of 
the CRT with something heavy. Still, that's just my judgement...

As for implosion risk in using heated wire to remove the faceplate... 
Hmm. I was careful where I postioned myself when I removed the plate on 
the HP 250 screen just in case, plus I went evenly from the corners a 
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 
another matter as it's so thin, which is really why I was being careful 
about the heating). Just a case of being careful though I suppose.

*I recall breaking TV CRTs apart as a kid and the glass at the front is 
amazingly thick. Bricks bounce off happily without damaging the screen 
at all.

cheers

Jules