Handling CRTs

[ppppenguin]

These pictures were sent to me by a friend who removed the bonded faceplate from a CRT. He reckons it was attached with something dissolved in Xylene or similar, most likely Canada Balsam. Apparently it sticks rather better than to a blanket. The first picture shows the job about 80% done, the second is the finished job. The small red marks are blood. He wrapped the bulk of the CRT in industrial cling wrap as a precaution agaisnt implosion.

He survived the experience.

[Heatercathodeshort]

Its all well and good for guys like us who have been in the service trade for 40 years. We know the dangers of CRT's especially now some of which are well over 50 years old and no doubt a lot more unstable now them they were then. The indended life would have been 10 years maximum.
A lot of guys on this site are completely unaware of the dangers of unprotected CRT's and a few earlier threads will turn up some horrific cases the dangers of which the more experienced guys alerted the members to. For the newcomers to old telly servicing I can only offer the following advice.

A CRT imploding at close range will send millions a fragments of glass in all directions slashing skin and possibly causing extensive damage to eyes,
[blindness] wrists and body to say nothing of whoever else may be in the room. Believe me I am the very last person on this earth to exagerate 'Health and Safety' but I cannot stress too heavily the dangers of old unprotected CRT's. They must be treated with extreme caution at all times and in no way subjected to strain, stress or undue fast changes in temperature [resoldering eht connectors] etc. While servicing sets with the crt removed, place the crt in an old style hession sack or strong cardboard box that will not be torn apart should the worst happen. Wear goggles when handling an exposed tube and at all times treat with great respect.

Remember these tubes are now very old and glass is an unstable item. We don't want headlines such as 'OLD TV BLEW UP AND BLINDED VINTAGE TV ENTHUSIAST' [and his cats not been seen since..] Its would be just the excuse the 'environmental' brigade would require to pass legislation to take all our old junk for 'processing' at the local tip......Sorry if I'm going on a bit but I've seen tubes pop and you don't want to be there! Regards and no insults intended. John.

[Heatercathodeshort]

No need to go over the top with worry. Just take reasonable and sensible precautions. Wear goggles, gloves and put the cat out...Don't put 'naked' tubes on the floor awaiting the decent of that mains transformer from the bench...Think what you are doing and take care! To prove a point try scoring and snapping old window glass. When I say old I mean say 40 years. It shatters and never follows the line. I repaired some windows in my mothers Edwardian house many years ago. They were stained glass known to the local glazier as 'Cathedral' from the arts and crafts movement. It was impossible to cut and cracks ran at all angles. New glass is like cutting perspex! Good luck and play safe. If any forum members have any concerns or questions about CRT replacement please feel free to thread or Pm Its not a problem. I can honesty say I have changed thousands.
Regards John.

[Skywave]

Just for the record - I'm sure that a lot of you know this, but we get a fair number of "starters" on this Forum - and it might just save someone from injury.

I was always taught that when an old CRT was to be disposed, the first step was to "let it down" - i.e. destroy the vacuum - and that the safe way of doing this was to put the tube face down in a cardboard box and with an eight ounce hammer, give a sharp blow to the very end of the tube where the pins come out - aiming at the central plastic spigot. You get a slow "hiss", and that's the end of that.

Similarly, on the safety issue, NEVER carry / move a CRT by holding it by its neck!

I'd be interested to receive feedback from other members on these two techniques - just in case I've been doing it wrong all these years!
I'd hate to give out "ex cathedra" advice like this - later find out it's wrong / inaccurate - and someone's got hurt as a consequence.

Al / G8DLH

[FERNSEH]

Originally Posted by slidertogrid

The early round crts that I have seen seem to be made of a lot thinner glass and sometimes have tiny air bubbles it them I think if I was fitting one of those I would wear a lot more protection

Here's an example of an early CRT. The picture shows the CRT fitted to my Cossor 137T It's a really scary thing, it's very thin glass.

DFWB.

[molochkartovski]

"I was always taught that when an old CRT was to be disposed, the first step was to "let it down" - i.e. destroy the vacuum - and that the safe way of doing this was to put the tube face down in a cardboard box and with an eight ounce hammer, give a sharp blow to the very end of the tube where the pins come out - aiming at the central plastic spigot. You get a slow "hiss", and that's the end of that."


I've always used pliers or cutters to beak the seal off the end it's the same principle though. A nice satisfying hiss and it always seem to take a lot longer than you would think to fill up with air
I wouldn't like to try it on anything pre war or as thin as Fernseh's though !

Richard

[pmmunro]

I would agree with the general principles of the advice which G8 relays, with
a few of refinements.

For face protection, a full-face, visor type, shield is probably better than googles and will save your looks as well as your sight. It's also less likely to steam up although somewhat claustrophobic. The cost is only a few pounds from most engineering suppliers or garden machinery dealers. Add a pair of welders GAUNLETS - not gloves (only about £2.00) to protect the hands and forearms. (Also useful for driving/firing steam engines when not welding or weeding).

When carrying any CRT by the bowl, keep the thumbs well clear of the EHT connector. The tube is effectively a glass dielectric capacitor and can store charge for months, if not indefinitely. Allegedly, several accidents have resulted from dropping tubes due to this cause.

For disarming tubes, I would very much agree that the safest method is to break the seal on the evacuation tube. This way the main structure is undamaged. Ideally, the tube should be scored with a small triangular file, as for cutting laboratory glass tube, then broken, but impact using a rod between hammer and evacuation tube is probably a reasonable compromise. (Avoids hitting the neck if the aim is poor). In all cases, the tube should be well enclosed in at least a double walled cardboard box - tube face down).

Has anyone got any views on the vast quantities of TV sets/Monitors left on footways for collection with general rubbish? Does anyone know if the people who collect the rubbish have any guidance on this matter? As for "recycling centres", is anyone interested in attempting the dangerous potential campaign to persuade them that it would really be safer to allow knowledgeable people (ie forum members) to remove old TV sets for trully safe disposal?

PMM

[Sean Williams]

Erm, Sorry, but this would not happen - CRTs are now classed as hazardous waste, and strict guidelines are in place to cover the disposal of them....

Take a look at this facility.....
http://www.brucemetals.co.uk/crt_recycling.html

Sad really, especially when most of the TV sets that are being dumped either work, or just have minor faults........

Cheers
Sean