Here's something that I've never seen before. I have boxes of old bulbs I put aside, and pulled out two flats of 14V large globe white frosted. I am wiring the buildings and use these large bulbs because I like the glow. These are Japanese bulbs probably from the 1950s.
The very first bulb I pulled of the tray lit very briefly and then went dark. I had to look at it twice to figure out what was up with it:
The bulb is assembled, then a bit of soldier is used to seal it. This one never got the soldier. It's the only one of these fifty.
I always thought the filament was sealed inside the glass globe. Maybe this one had two faults?
I'll out these on the freight sheds and in the buildings.