CRT implosions

[Vintage Computer Festival]

On Tue, 4 Oct 2005, Jules Richardson wrote:

> 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've stored monitors outside in the baking sun during summer for extended
periods of time.  I've had the CRT heat up so much that it quite literally
burned you if you touched the surface.  However, none ever spontaneously
imploded.  My guess is that you'd have to have enough heat that the glass
began to melt before it imploded, and even then it wouldn't implode but a
gapwould open and the tube would re-atmospherize.

Still, if I were to do what Jules did, in the very least I'd wear safety
goggles and some leather gloves.

> *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.

Yep.  There's 6-8 pounds of lead in a CRT, with the majority of it (90%+)
being in the face, which is also by far the thickest part.  This is to
protect viewers against the X-ray emissions.  I imagine it also
contributes to the structural strength of the tube.

-- 

Sellam Ismail                                        Vintage Computer Festival
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International Man of Intrigue and Danger                http://www.vintage.org

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