If it is actually radium, it's difficult to imagine that it would glow for more than a few seconds.
Here is a Nixie Tube Clock that my son built from a kit for me several years ago.
I found a glass case to keep it in which keeps the dust off of it and protects it.
It keeps good time and goes through various cycles during the day to keep the tubes working well.
Half life of radium 226 is 1600 years. The issue with these not glowing has nothing to do with radium but degredation in the paint.
The half-life speaks to radioactivity, not necessarily to luminescence. Phosphor deterioration will kill the glow. Radium was also used in relatively tiny amounts in the late '50s and early '60s. If you can detect a glow in a 60+ year old radium watch or clock that lasts for more than a few seconds, I'd like to see a photo or video of it.
The glow is persistent, it's just very faint
For what period of time?
All time. I don't see what is so confusing about the word "persistent".
What's confusing is that the phosphorus paint almost invariably degrades until there is no glow whatsoever. I don't doubt your claim of excellent vision, but have never heard other similar accounts of extended glow in such old lume.
I have a 1960 Bulova military watch with the original radium lume that does emit at night, albeit very, very faintly.
Thanks. Because the late examples, like yours, used much less radium, the phosphorus paint would typically last much longer. Because radium was typically used in much higher amounts earlier in the century, the paint would degrade more rapidly.
Of course it is impossible to know what concentrations were used in each case, but I have never previously heard of an early radium watch or clock glowing for more than a few seconds, let alone all of the time. Some of the earlier ones that I own don't even glow under a black light!
I use a Westclox Moonbeam from the early 50s. It wakes you with a flashing light. There is an audible alarm that comes on after 5 minutes or so, but I've never needed it--the light works every time, and it's MUCH less annoying.
What's confusing is that the phosphorus paint almost invariably degrades until there is no glow whatsoever. I don't doubt your claim of excellent vision, but have never heard other similar accounts of extended glow in such old lume.
