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Oscilloscope CRT implosion
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coppice:

--- Quote from: vk6zgo on March 12, 2024, 08:41:34 am ---
--- Quote from: adriansmith31 on March 11, 2024, 05:55:52 pm ---I smashed an oscilloscope CRT to see how much of a bang it went with. Very stupid I know but I did bag it up to avoid glass going everywhere.

Demonstrates how dangerous these are if handled incorrectly. Glass very thin and no implosion protection. It was gone in 3 frames so camera didn't quite capture the full boom.

Long version https://youtu.be/_sL1OY1ONiU

Short version https://twitter.com/adriansmith31/status/1766966799898198085?t=eVceijRWaMCEeEk3h-fx9Q&s=19

--- End quote ---

A large Scientific flask at atmospheric pressure would smash nearly as "spectacularly".
The very large RADAR PPI tubes that were widely available as WW2 surplus are another story, & much of the "implosion" mythology dates back to them.
Early TV tubes were not much better, but anything produced since the early 1960s is quite difficult to cause to implode.

--- End quote ---
Early 60s TV still had a tube with a separate armoured glass sheet in front of them. You need to get to the mid 60s before the bonded face tubes, with a metal band around them, took over. That's the innovation that made them very hard to damage in a spectacular way.
andy2000:
Early CRTs had no implosion protection, and required a separate safety glass.  In the 60's they started bonding the safety glass to the front of the CRT for a more modern look, and less glare.  In the 70's they got rid of the bonded safety glass and went to the tensioned metal band around the edge to reduce cost and weight.  This system was used up until the end of CRT production.

I was disposing of some CRTs about 20 years ago, and thought it would be interesting to just toss them in a dumpster while still under vacuum.  One was a modern tension band CRT, the other was a 60's CRT with no implosion protection.  The one with the tension band broke with little drama.  The one without went off like a bomb when it hit the bottom of the dumpster, and glass rained down all over the place. 
vk6zgo:

--- Quote from: coppice on March 12, 2024, 02:51:03 pm ---
--- Quote from: vk6zgo on March 12, 2024, 08:41:34 am ---
--- Quote from: adriansmith31 on March 11, 2024, 05:55:52 pm ---I smashed an oscilloscope CRT to see how much of a bang it went with. Very stupid I know but I did bag it up to avoid glass going everywhere.

Demonstrates how dangerous these are if handled incorrectly. Glass very thin and no implosion protection. It was gone in 3 frames so camera didn't quite capture the full boom.

Long version https://youtu.be/_sL1OY1ONiU

Short version https://twitter.com/adriansmith31/status/1766966799898198085?t=eVceijRWaMCEeEk3h-fx9Q&s=19

--- End quote ---

A large Scientific flask at atmospheric pressure would smash nearly as "spectacularly".
The very large RADAR PPI tubes that were widely available as WW2 surplus are another story, & much of the "implosion" mythology dates back to them.
Early TV tubes were not much better, but anything produced since the early 1960s is quite difficult to cause to implode.

--- End quote ---
Early 60s TV still had a tube with a separate armoured glass sheet in front of them. You need to get to the mid 60s before the bonded face tubes, with a metal band around them, took over. That's the innovation that made them very hard to damage in a spectacular way.

--- End quote ---

In Australia, bonded face tubes were appearing in around 1962/3.---that is still "early 1960s" to me!
The bonded face tubes didn't have a metal band, that was a later innovation which controlled the stresses so the tube was very unlikely to break catastrophically, whilst allowing the tube maker to do away with the heavy bonded face.
CatalinaWOW:
I used to treasure the armor glass window from the front of a 1950s TV.  It protected me from a number of the unsafe experiments I ran in my dumb teen years.  And I guess since the glass kept any shards and liquids from my skin and eyes those experiments weren't really unsafe.
vk6zgo:

--- Quote from: andy2000 on March 12, 2024, 03:27:29 pm ---Early CRTs had no implosion protection, and required a separate safety glass.  In the 60's they started bonding the safety glass to the front of the CRT for a more modern look, and less glare.  In the 70's they got rid of the bonded safety glass and went to the tensioned metal band around the edge to reduce cost and weight.  This system was used up until the end of CRT production.

I was disposing of some CRTs about 20 years ago, and thought it would be interesting to just toss them in a dumpster while still under vacuum.  One was a modern tension band CRT, the other was a 60's CRT with no implosion protection.  The one with the tension band broke with little drama.  The one without went off like a bomb when it hit the bottom of the dumpster, and glass rained down all over the place.

--- End quote ---

Funny you should say that.

When I worked at a TV studio, we regularly changed the picture tubes of Picture Monitors, disposing of the old ones in a large dumpster.
Throwing them in rarely broke them in any way, so we normally poked the neck with a long piece of what in Oz is called a "star picket".
On one occasion, we had to dispose of some smallish late 1950s CRTs.
They did break, but not spectacularly.

Before that, I remember throwing some TV tubes out at the local garbage dump.
Even though they fell a fair distance, they didn't break, so concerned, I told the tip attendant.
He replied that they seldom did, but that the big metal wheeled compactor made short work of them!
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