Black PETG definitely looks better than cyan for this job:
Holding the plate cap to the tube with a thin ring of opaque epoxy cuts down on the glare under its edge:
Fire in the bottle!
It’s still running basically the same Arduino code as before, but I have some ideas about that…
2 thoughts on “Vacuum Tube LEDs: Fully Dressed 21HB5A”
The reflection of the surprisingly regular mottling of the lower mica is unexpectedly nice.
The mica sheets in those 21HB5A tubes look like they have a powdery white coating, quite unlike the usual shiny dark-silver mica sheets in my other tubes, that lights up wonderfully well under the LEDs.
Peering at the bottom of another 21HB5A, I think the mottling comes from refraction around the pins. Each pin has a glass cylinder melted around it; they may have put a sealing bead on each pin, combined those with a glass tube base, then melted that whole assembly onto the tube envelope. Plenty of forgotten tech involved in that process, fer shure!
Comments are closed.