[Milsurplus] Making Tubes

[Robert Nickels]

I work for Honeywell, and until RoHS put the kibosh on mercury, our 
plant here made the millions of mercury switches used in all those round 
thermostats.  In fact, that's why Honeywell acquired this company in 
1950.  Mercury switches are basically glass tubes with hermetically 
sealed wire elements that are made in much the same way as a vacuum 
tube, so that's where the process and equipment were borrowed from.  
Everything was automated, and even though the machines were originally 
designed and built in the 50s, they worked reliably until the day they 
were turned off for the last time.   Cam-driven dial indexers don't care 
about Y2K or viruses!   As one tech told me "it's just glassblowing on a 
production scale".

Mercury is not to be taken lightly, and this department had a spotless 
safety record.  But I know some mercury operations, and probably some 
vacuum tube manufacturing sites ended up as Superfund cleanups,  just 
because of the way things were done "back then".

73, Bob W9RAN