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Discussion Starter · #1 ·
30" TV weight 150 pounds. Can it really be that it's just the tube glass that it's so heavy? o_O


I know they are using some kind of leaded glass to prevent X-ray radiation from the electron beam, is that why it's so heavy?
 

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Yep its the CRT weight. You could get a big 50" plasma display and weighs only around 100 pounds, less than a 27" CRT!
 

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Quote:
Originally Posted by Marconelly
30" TV weight 150 pounds. Can it really be that it's just the tube glass that it's so heavy? o_O


I know they are using some kind of leaded glass to prevent X-ray radiation from the electron beam, is that why it's so heavy?
Ha, ha. :D. All CRT TVs are heavy. Use common sense.
 

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Discussion Starter · #4 ·
Yeah, but what makes the CRT so heavy? Is it the leaded glass? Is it those electron beam steering coils? Do they put some crazy heavy metal shielding around it nowadays to make picture more stable? I just have a problem understaning how a part made of hollow glass can be so heavy.
 

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well, anyone feel free to correct me if I'm wrong, but here's what I've been told...


Old CRTs had rounded screens for a reason, the glass can withstand a lot more force that way. Think of ancient architecture... there were archways, not square doorways because the force gets distributed down the sides of the arch.


With flat glass, the strength of the glass itself has to support all that pressure, so to make the screens flat they have to be very thick glass (thicker=stronger)


Oh and the pressure is coming from the fact that the inside has to be under vacuum for the CRT to work properly. On the other side of the screen is atmospheric pressure, approx 14.7 pounds per square inch at sea level, if I remember correctly... so 14.7 times the area of your screen means a pretty large force.


This is why when you go to lift a CRT, it feels like all the weight is in the front where the screen is.
 

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Quote:
I just have a problem understaning how a part made of hollow glass can be so heavy.
The front of the tube is at least a half inch thick. Glass is heavy.

It has nothing to do with weather the screen is curved or flat.

The 'Lead' in the glass is an oxide, not metallic lead...you wouldn't be able to see through it if it was.
 

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Quote:
Originally Posted by devo6273
well, anyone feel free to correct me if I'm wrong, but here's what I've been told...


Old CRTs had rounded screens for a reason, the glass can withstand a lot more force that way. Think of ancient architecture... there were archways, not square doorways because the force gets distributed down the sides of the arch.


With flat glass, the strength of the glass itself has to support all that pressure, so to make the screens flat they have to be very thick glass (thicker=stronger)


Oh and the pressure is coming from the fact that the inside has to be under vacuum for the CRT to work properly. On the other side of the screen is atmospheric pressure, approx 14.7 pounds per square inch at sea level, if I remember correctly... so 14.7 times the area of your screen means a pretty large force.


This is why when you go to lift a CRT, it feels like all the weight is in the front where the screen is.
Well of course a rounded piece of glass IS stronger but the problem with a straight screen is how to beam the electrons in such a way to get straight lines. How to make the lines look straight on a flat screen was up to some time ago far from trivial.
 

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Yup...that's why the Sony 40" tube CRT will probably the biggest CRT made ever ....that sucker weighs around 300 pounds. I would agree with most eveyones comments regarding the reasons why those glass tube weigh so much. Could you imagine a 42" widescreen CRT..that would be nice but would probably be around 350-400 pounds...I'd get one

:)


Cheers
 

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Quote:
Originally Posted by TonyBDA
The front of the tube is at least a half inch thick. Glass is heavy.

It has nothing to do with weather the screen is curved or flat.

The 'Lead' in the glass is an oxide, not metallic lead...you wouldn't be able to see through it if it was.


Just to clarify this point, lead is still lead, whether is is an oxide or not and still very heavy. Leaded glass is twice as dense as basic borosilicate glass (~6.2g/mL vs ~3g/mL), but also much stronger. This should contribute significantly to the weight. The glass used is probably much heavier than most glass used in other applications (windows, etc.)
 

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Originally Posted by PULLIAMM
Look at the bright side: It would take a really committed thief to steal a big CRT!
Ha, I love it! I was thinking the same thing of my potential purchase of a 34" CRT. :D
 
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