How can you tell if an old clock dial has radium?

[Thyratron]

Recently, I picked up an old Baby Ben clock (probably mid- to late-sixties in appearance) for a dollar, in non-working condition. It has the luminous hands and dial numbers, greenish in color, which makes me wonder: is it radium paint? I thought most of that was phased out by then, but is there any way to tell short of using a geiger counter (which I don't have, and probably don't really have any easy access to)? It only really glows after it is put into light; I let it sit in the dark bathroom overnight, and by morning the dial was just barely (I mean really, really faintly) visible in the dark room. Any of you clock people have any idea?

[goraman]

lick the numbers and if your hair falls out it's radium.

[Celt]

Lmao!

[OvenMaster]

http://en.wikipedia.org/wiki/Radium

"Historical uses

Radium was formerly used in self-luminous paints for watches, nuclear panels, aircraft switches, clocks, and instrument dials. More than 100 former watch dial painters who used their lips to shape the paintbrush died from the radiation from the radium that had become stored in their bones. Soon afterward, the adverse effects of radioactivity became widely known. Radium was still used in dials as late as the 1950s. Although tritium's beta radiation is potentially dangerous if ingested, it has replaced radium in these applications.

During the 1930s it was found that workers' exposure to radium by handling luminescent paints caused serious health effects which included sores, anemia and bone cancer. This use of radium was stopped soon afterward. This is because radium is treated as calcium by the body, and deposited in the bones, where radioactivity degrades marrow and can mutate bone cells. The litigation and ultimate deaths of five "Radium Girl" employees who had used radium-based luminous paints on the dials of watches and clocks had a significant impact on the formulation of occupational disease labor law.

Tom

[Thyratron]

I should have expected that first response. I guess I should have said without tasting/licking/eating/otherwise ingesting the clock.

[OvenMaster]

There's no harm unless you do just that:

http://www.hps.org/publicinformation/ate/q3561.html

[Eric H]

Maybe your local Police Bomb Squad has a Geiger counter,of course if it's Radium they'll probably confiscate it. :stupid:

[guptonr]

If you have have to hold it to light to make it glow and its brightness fades it's not radium. I've seen some old aircraft intruments that had a little bit of radium left on them. The marks glowed brightly didn't need to be "charged" and didn't fade over time.

[ByteWrangler]

Store it in a dark place for a day or so. If it still glows brightly in the dark, it's probably Radium. If it glows brightly only after exposure to bright light or UV, it's not.

You beat me by a few seconds, guptonr!

[Cadillac Kid]

My best friend's brother returned from his tour in the Air Force in the late 60's with vial of Radium paint. The boys decided to surprise their sister by painting stars on her bedroom ceiling. The sister died about 20 years later at age 30 of Leukemia. I still wonder if her death was related to that.

[goraman]

In Truth Radium has a life expectancy of 20 years max so if it still glows it probably isn't radium. But I had to have some fun O.K.

[Thyratron]

My best friend's brother returned from his tour in the Airfroce in the late 60's with vial of Radium paint. The boys decided to surprise his sister by painting stars on her bedroom ceiling. The sister died about 20 years later at age 30 of Leukemia. I still wonder if her death was related to that.

Wow. That's scary. It does make you wonder. It seems to be a very interesting, yet dangerous material if handled improperly.

[Thyratron]

In Truth Radium has a life expectancy of 20 years max so if it still glows it probably isn't radium. But I had to have some fun O.K.

Do you mean the "glow" lasts about 20 years? I thought the actual radiation levels stayed intact for centuries.

[Switchblade]

Does your member name have anything to do with this? :scratch2:

[goraman]

We had some federal registered Radium exit sighns and they lost there glow after 15 years and had to go through the proper chanels to be disposed of.Your clock isent a threat reguardless unless you ingest it.

[Thyratron]

Does your member name have anything to do with this? :scratch2:

Haha, that's a pretty funny point that I never thought of. Actually, I picked the name just because I always liked the way it sounded and since it's a type of vacuum tube, it's at least somewhat relevant to the electronics focus of these boards (although probably useless in an audio sense). In all honesty, I don't think I've ever actually seen a thyratron "in person"!

[avionic]

In Truth Radium has a life expectancy of 20 years max so if it still glows it probably isn't radium. But I had to have some fun O.K.
life expectancy
You mean half life as in radiation decay rate.:scratch2:

[mywifespissed]

I talked to a physicist at the University of Washington who told me radium has a 1/2 life of 25,000 years. It's not something to take lightly. One kilo of radium under one pint of water will bring it to a boil from room temp. every half hour for thousands of years. I am a watchmaker and handle it pretty regularly. I used to be careless with it and it creeps me out a bit to think of how many flakes I have ingested before I realised the danger. I now store the stuff in lead foil when removing it from watch hands and markers.

There is a book called "The radioactive Boyscout" (awesome BTW), that chronicles the true story of a brilliant 16 year old kid, working on becoming an Eagle Scout, who made a working breeder reactor in his parents tool shed using radium he scraped off of old Big Ben clock dials, as well as a radioactive vial of paint he found at a thrift store. He carried a geiger counter while he browsed. He will no doubt die of one or another type of cancer. A government group in spacesuits swooped in and took the shed as well as a goodly amount of soil beneath it.

Radium also decays into radon gas, a known cause of lung cancer. It's probably best to not have a radium clock in the house. I have read that a person who uses a radium dial clock by their bedside for decades will receive double the radiation exposure of the average person.

[markthefixer]

We had some federal registered Radium exit sighns and they lost there glow after 15 years and had to go through the proper chanels to be disposed of.Your clock isent a threat reguardless unless you ingest it.

Are you sure they weren't tritium ? That seems to be the requisite time span:

Tritium is radioactive with a half-life of 12.32 years. It decays into helium-3.

Radium has 4 predominately natural isotopes, with the half lives being:
1602 years (Radium 226 is a product of Uranium 238 decay), alpha emitter
6.7 years (Radium 228 is a product of Thorium 232 breakdown), beta emitter
11.4 days alpha emitter
3.6 days alpha emitter
in a mix that loses about 1% of its activity in 25 years, being transformed into elements of lower atomic weight with lead being the final product of disintegration.

When marie curie was presented with an ounce of radium in 1921, it was enclosed in 110 pounds of lead.

Radium bonds in the body like calcium, concentrating and becoming chemically bonded in the bones. Then, it can bombard cells with radiation at close range, which may cause bone tumors or bone-marrow damage that can give rise to anemia or leukemia..

Radium was still used in dials as late as the 1950s. Although tritium's beta radiation is potentially dangerous if ingested, it has replaced radium in these applications. Generally tritium will be found in sealed glass capsules.

Tritium IS used in exit signs. Several Curies worth in each...

The danger is when the stuff (both) becomes airborn, thus being introduced in the body.

mywifespissed, go walk by the Nuclear Medicine Department of a local Hospital and see if you set any alarms off. Some folks undergoing Cancer therapy in the New York area either carry letters or are registered, so when they trigger the radiation detectors hidden in the choke point approaches to New York they don't end up in the hoosegow...

In Illinois, a load of steel that had been contaminated by a radioactive cesium source from a cancer therapy machine that was split apart in a mexican junkyard triggered off the detectors in a State Cop's car and started a real kerfluffle as they tracked down what happened...

And I have a working Gieger counter in the house...

[old_tv_nut]

I had a wristwatch with radium (not tritium) dial in the 60's - it was much more active on the Geiger counter (at the Museum of Science and Industry where I had a summer job) than the radioactive sample they gave us to demonstrate the counter.

Tritium radiation output is much less penetrating and is stopped by the glass cover.

Materials that glow only after exposure to light are not radioactive, and in fact most are non-toxic, and are used in glow-in-the dark toys. I have a glow-in-the-dark statue of St. Claire of Assissi, patron saint of television, watching over me right now. - Wonder if she can counteract the exposure to that radium watch dial?