I own this beauty since 1995

Hello, i think it is a mercury switch, perhaps from 1910-1930.

[Sean Williams]

Nope,

Its a Mercury Arc Rectifier

[evingar]

It's cute. A nice manageable size. It would make a good (running) display piece if correctly mounted.

Thanks very much, when i found it, it was full of mercury, i took it apart for security reasons.

Do you know an exact manufacturing date?

[evingar]

Ah, I missed that it didn't have mercury - will have to be a static display then. I'm no expert in these things, so can't give you a date. I guess manufacturer and model type will help someone give you an answer to that, if you know them.

Yes, in this 25 years it has been very bad saved, in a box full of old electrodinamic speakers, variable capacitors and others metallic radio parts in my mother´s house. A few days ago, i visited her and recover it to make a beautiful static display as evingar said.

I accept ideas of how to display it.

Thanks

[Diabolical Artificer]

Without the mercury it won't run obviously, so is like Xmas tree lights switched off - pointless to display no?

Andy.

[trh01uk]

Originally Posted by Aitor Eneko

Thanks very much, when i found it, it was full of mercury, i took it apart for security reasons.

Surely the glass was intact when you first got it? Why was mercury inside a sealed glass envelope a "security threat"?


Richard

[John M0GLN]

Originally Posted by Diabolical Artificer

Without the mercury it won't run obviously, so is like Xmas tree lights switched off - pointless to display no?

Not pointless at all, I have a Sterling horn speaker from the 1920's that comprises the base and horn only, no coils or diaphragm but it looks very attractive as a display item in our dining room.

John

[evingar]

Yes, I would agree. Personally, I would have liked it working, but it's still an impressive (and now safe in the event of damage) bit of glass work. It maybe possible to "strategically" position some UV LED's to convey what it would look like in operation.

[mark2collection]

Slightly OT perhaps but, I've always fancied including a Mercury Arc rectifier in one of my projects.

The only one I came across was a bit expensive and, huge! Looked as though it would run London Underground.

These rectifiers, especially when running, look as though an octopus is receiving 'therapy' from Igor.

Back OT, they have a look about them

Mark

[evingar]

I do have some sympathy for Aitor.

There is a problematic quantity of mercury in these things - especially the larger ones.
Although people of my age used to run the stuff through our fingers at school, a mercury spill has now become a "big deal", entailing lots of expensive people in environmental suits.

Additionally, it's not obvious to me how (in the UK) you could dispose of sizeable quantities of the stuff with out a lot of expense. I'm pretty sure local recycling centres wouldn't be willing to take it in.

60 ml of mercury. I have it in a Pyrex container

[The Philpott]

Should be able to do something for display using LED's from the blue range through to the UV range. As it has been made 'safe' is might even be possible for it to be lit from the inside..? It might be possible to fog the inside of the glass with smoke to made the light spread, but once that is done there is no way to remove it properly.

To complete the illusion of operation I suppose it would have to be in a frame with wires hanging from the anodes/cathode, and an electromagnet clamped around the mercury dipper arm, etc. The buzz from a cheap concealed arc welder transformer would be very effective- and as you're not welding with it I do not think the duty cycle would be a problem. All this is going to take up quite a lot of room.

Dave

[Peter.N.]

They had some huge ones on Chelsfield station in my school days, supplied 600v for the third rail system. I used to stare through the windows fascinated.

Peter

[The Philpott]

A 3 phase 'bulb' c/w Hg appeared for sale a few days ago, only to be withdrawn because the seller 'had made an error in the listing'. (whatever that may mean)

I have been saved the strain of a click test with mine, since when withdrawn in inverted position from its intermittently warm storage space, the tiny little drops that had condensed all over the inside in the last 2 years fell back into the pool with audible 'tinks'. It appears it has a vacuum.

Dave

[Maarten]

Originally Posted by Aitor Eneko

60 ml of mercury. I have it in a Pyrex container

While mercury on itself is a nice to have item now it can't readily be bought, chances are it will cause more spills and contamination when it's outside the valve. Even so, remaining mercury will gas out of the broken valve over time. Gas is potentially more harmful, but it's only small quantities. Don't go sniffing it on a hot day, though, and put it in an at least somewhat ventilated area. Preferrably not your bedroom.

Thinking things through, I really don't get it. It was a safety hazard as a glass tube in a box with filled heavy items, but on display, especially in a nice case, nothing would happen to it.

All that said, the mercury was and is probably not really that much of a problem in either case, as long as you don't spread it around actively, heat it or put it in your food. Label the container, close it airtight and put it away where it can't fall or break.

Only question is now with preservation. I'd preserve it if only for the looks instead of the former technical value. You could make a nice display case with some violet LED's in it. I bet it would look nice that way.

[Argus25]

For God's sake, metallic mercury is pretty safe. 50% of an amalgam filling in your mouth is metallic mercury, as you eat and grind your teeth you swallow it, few toxic effects are proven.

Mercury is really only toxic in its organic complex forms.

Sure, you don't want to go sniffing the vapor, but the number of people who have over reacted to the perceived threat of metallic mercury are about equal to those who believe lead head nails will poison you (but fishing sinkers won't) and that Lemmings really do commit suicide.

[Maarten]

Metallic mercury is slighlty more dangerous than metallic lead because it's a fluid, but I fully agree that it's just not that dangerous as long as you know where it is. I've used the toxicity in above post mainly to indicate that shedding the mercury at best worsend the safety situation. To prove an action to be superfluous or slightly harmful is best done accepting the premise of that very action.

[stuarth]

Just don't take your container of mercury on an aeroplane in case it escapes. I believe it doesn't mix well (or do I mean it mixes too well) with aluminium.

S