I was reading an article about wall switches and came across a mention of how they used to be constructed of mercury. The article went on to say that aside from the obvious problems associated with mercury, the switches themselves were superior in action, quiet, longest lasting and most energy efficient. It kind of begs the question to me - do any of you all still have mercury switches in your house and if so - are they all that wonderful?
came across a few today still working fine in an apt. the only time i seem to replace them is when asked to do so.as far as better probabaly seeing things made today are not made to last, no money if your not periodically replacing them.
Back in the 50's we had some in our house. They were silent and smooth operating. Most switches today are pretty quite, but back then, the normal switch made a pretty loud click. Back then, yes, they were all that wonderful. Today, even a cheap switch performs well, is easy to flip, and is virtually silent.
I also recall having a bottle of mercury in the house. We used to play with it and make shiny pennies. Today, we'd be tossed in jail for that and the street would be evacuated. We also put Mercurochrome on cuts to help them heal.
There are four of them in the thermostat for my heat pump. According to the inspector who inspected the house before I bought it, my heat pump appears to be from around 1977, which is before mercury started being phased out of homes, I believe.
Wikipedia has this to say about mercury switches in thermostats:
Mercury switches were commonly used in bimetal thermostats. The weight of the movable mercury drop provided some hysteresis by moving the bimetal spring slightly beyond the point it would normally assume, thereby holding the thermostat off slightly longer before flipping to the on state and then holding the thermostat on slightly longer before flipping back to the off state. The mercury also provided a very positive on/off switching action and could withstand millions of cycles without degradation of the contacts.
I used to have a small vial of mercury, which I obtained sometime in the early '70s, when I was around 12. Me and the other kids would take it out now and then and watch it roll around and poke it with things. In the vial, I kept a screw, which floated on top of the mercury. It was very cool.
It's funny to think that what we considered a toy back then and showed our friends in school would probably prompt an evacuation if a kid brought it to school today.
I don't know what happened to it. I think I lost it during a move.
they were mainly used because they were silent. Thermostats still use them if they're not electronic. The only drawback on a standard spst mercury switch is that it HAS to be mounted in the standard fashion only. Can't be horizontal or on a horizontal surface.
I saw a show on tv once a long time ago they had a quantity of mercury in a cake sized pan with a crescent wrench floating on it. Seems weird when you see that.
Mercury weights 156 pounds a gallon. Someone dumped two gallons by the road a few miles south of me. You can imagine the excitement that generated.
ya, how in the world do they collect it ? Shop vac?
I'm sure they are totally efficient, but how inefficient are the other switches? Unles they are getting warm, even if you can't feel the didfference, I think they are also totally effficient.
I'm sure at the end of their life they get warm, but mine are all 28 years old and as good as new afaict.
I have mercury switches in my car, to turn on the trunk light and the dome light, and I've used them for burglar alarm switches in cars also. But none of them get used mcuh.
I have loads of mercury, 10 or 20 cc, half that my father, a dentist, gave me when he was alive and I was 6 or 7, and about an equal amount that I guess I inherited after he died. His nurse, Grace, must have remembered that I would want it**. It's been 52 years, and I've been saving it for something special. The last 10 years I've lowered my standards and would use it for something not special, but nothing has come to mind.
Don't worry. I haven't poisoned myself. Playing with it was no fun and only made it dirty for no purpose. I think I knew that at age 8 without even trying.
**I also got a whole bunch of cheap, plastic, hollow, small, cars and buses, that he would give to kids after their dental work, but even at the age of 8, I didn't want that stuff. I would have been happy to get one piece after a dental visit, but getting 40 pieces, well, I would rather play with my brother's Lionel train than with hollow cars and buses. There was a third thing in that box too, that was only slightly interesting at the time, but I don't remember what it was.
Exactly. In comparison to the big click, which could probably wake most people who were sleeping, they were great. I think they were the difference between middle class and upper middle class. (Expecially if you had to hire an electrician to put them in.)
Yep.
Did you ever get merthiolate? Which one stung and which one didn't?
They work forever. But no bells and whistles, like auto setback. I have them in 2 houses. I don't see any reason they'd be more energy efficient than any other thermostat, and they are certainly less efficient than a modern auto setback unit.
Bob
Merc vac.
Just kidding.
They *both* stung like a sonovabitch. Bactine is the one that didn't sting.
Mercury's dense, but not quite *that* dense.
13.6 kg/l * 3.78 l/gal * 2.2 lb/kg = 113 lb/gal
They are also explosion-proof. No exposed spark.
Dave
I hadn't thought of it from that angle. That would be useful in a combustible gas environment like a refinery.
I'll never trust the newspaper again. :(
I don't recall mercurochrome stinging. Merthiolate always stung, of course.
Same for any electronic switch such as a transistor.
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