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Any Carbon filament lamp fans in this forum??

old_tv_nut said:
A couple of curiosity items:
Do these replicas actually have carbon filaments, or are they low-temp tungsten?
Are they vacuum bulbs or inert gas filled?
Click to expand...
From the looks of them, the filaments are actually carbon, though exactly how close they are to what was used in the old light bulbs is unknown (the filament in the 1979 replica looks thinner than the one used in the 1959 replica, and vibrates noticeably if jostled). As for the insides of the bulbs, I don't know for sure; I'm guessing the 1959 bulb uses whatever GE was using for their 'large lamps' at the time, but have no idea who made the 1979 replica for the Thomas Alva Edison Foundation, or what they used.
-Adam
 
Very interesting. Thanks! I think I read somewhere that the bulbs for theater marquees were always vacuum filled because the gas filled ones tended to shatter when struck by cold rain or sleet.
 
Allow me to quote myself:
AdamAnt316 said:
Anyway, I've still been collecting the cool old-fashioned bulbs. Even bought a carbon filament bulb whose shape vaguely resembles that of the Centennial Bulb, though I don't think it was actually made by Shelby Electric (or that it would last anywhere near a century if lit continuously).
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Only took me two years plus, but I finally took some pictures of this mystery:
shelbybulb_off.jpg

shelbybulb_lit.jpg

No ID stickers, of course. The glass is a bit blackened, but not too badly. The envelope looks far more like a modern 'A' shaped bulb than the classic Shelby shape of the Centennial Bulb, but definitely rather different than the 'S' envelope normally seen on old carbon filament bulbs (and early vacuum tubes). Here's a picture of it at half brightness:
shelbybulb_half.jpg

And here's a close-up of the filament at half brightness, which has a curious 'S' shape to it:
shelbybulb_filament.jpg

And finally, a few of it cranked to about 110V on my Variac, which was about as comfortable as I was with getting close to full brightness:
shelbybulb_full.jpg
 
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