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Hi Bob,
Actually, it's not that heavy. One of the attributes of the early Pyrex tubes is that they are rather thin walled, and the front face is WAY thinner than later tubes. The highly convex front face and high strength Pyrex on the 20BP4 give it good structural integrity without needing to use very thick glass. Bottom line is that it is not particularly taxing to lift the tube out of the set. Something like 25-30 lbs total I would guess.
I can definitely say the 15GP22 in my CT-100 is significantly heavier than a 20BP4. More modern 21" B&W tubes are also heavier than a 20BP4, even though they are far less deep from neck to screen. They are heavier because of the thick glass they have on the screen.
The only thing that was a little scary about removing the 20BP4 from the Club 20 was that it had adhered to the rubber mask. I had to pry it up, and during that operation I worried a little working so close around such a big tube at a moment when the risk of implosion is somewhat increased.
I would sure love to know where people can find NOS 20BP4s these days. Chuck is very experienced and well connected!
Last edited by Tom Albrecht; 12-05-2014 at 09:13 PM.
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