Radium as a dial illuminator

[old man emu]

Luminous paint or luminescent paint is paint that exhibits luminescence. here are three types of luminous paints: fluorescent paint, phosphorescent paint and radio-luminescent paint. The type we are interested in is the radio-luminescent one.  Radio-luminescent paint was invented in 1908 and originally incorporated radium-226.  

 

Radium was discovered by Marie Curie in the last years of the 19th Century. Her first indication that there was something else in her samples of uranium was the glow. Radium is a radiological hazard, emitting gamma rays that can penetrate a glass watch dial and into human tissue. During the 1920s and 1930s, the harmful effects of this paint became increasingly clear. A notorious case involved the "Radium Girls", a group of women who painted watch faces and later suffered adverse health effects from ingestion. See https://en.wikipedia.org/wiki/Radium_Girls

 

Radium paint used zinc sulfide phosphor, usually trace metal doped with an activator, such as copper (for green light), silver (blue-green), and more rarely copper-magnesium (for yellow-orange light). The phosphor degrades relatively fast and the dials lose luminosity in several years to a few decades; clocks and other devices available from antique shops and other sources therefore are not luminous any more. However, due to the long 1600 year half-life of the Ra-226 isotope they are still radioactive and can be identified with a Geiger counter.

 

Radium paint was still used in dials as late as the 1970s. In the second half of the 20th century, radium was progressively replaced with promethium-147.  The half-life of ¹⁴⁷Pm however, is only 2.62 years, it is therefore not too suitable for long-life applications. Promethium-based paint was used to illuminate Apollo Lunar Module electrical switch tips, the Apollo command and service module hatch and EVA handles, and control panels of the Lunar Roving Vehicle. The latest generation of the radio-luminescent materials is based on tritium, a radioactive isotope of hydrogen with half-life of 12.32 years that emits very low-energy beta radiation. They are favoured by the military for applications where a power source may not be available, such as for instrument dials in aircraft, compasses, lights for map reading, and sights for weapons.  Additionally it is used in glowing novelty items and those light sticks waved around at rock concerts.

[willedoo]

I had one gauge, an American oxygen blinker, that was very radioactive. It was new old stock, WW2 era, the type used in most American planes like Mustangs, B-17's etc.. I ended up tossing it out as it was a bit too radioactive to keep for a collection display. The odd thing is, I have an O2 test kit with the same gauge and it shows no reading whatsoever. I've always wondered why; possibly they might have made a luminescent one for aircraft and a non luminescent one for ground crew test equipment. The only flaw in that theory is that in the days when those gauges were made, they might not have been concerned with the emissions, so might not have bothered with a safer variant for ground crew.

[Old Koreelah]

Long, long ago, I bought a Phantom Skull ring by mail order and was fascinated by it’s eye sockets glowing in the dark.

Am I gonna die?

[old man emu]

Old Koreelah - the Ghost who walks, cause he failed his AVMED.

[facthunter]

Yes.  Nev

[pmccarthy]

Yes, but a succession of descendants will take your place, giving the illusion that you are the ghost who walks, man who never dies.

[onetrack]

Looking into my crystal ball, I can see that you will surely die - but what will actually cause your death, is rather unclear.

[old man emu]

I knew a bloke who had a glass eye. His father had a crystal ball.

[red750]

11 hours ago, Old Koreelah said:

Am I gonna die?

Yes.       And so will everyone else.                

[old man emu]

At least his corpse with have a healthy glow.

[facthunter]

The people who used to paint those dials didn't fare well..  Nev

[pmccarthy]

Did anyone else burn match heads on a penny? Or was it the striker on the side of the matchbox that we burned? It gave a greasy product that glowed intensely in the dark. Great fun for a 12 year old.

[facthunter]

Be as a result of Phosphorus, I reckon. Nev

[onetrack]

Nope, never heard of the match head stunt. I must have had a less-exciting childhood. We only experimented with cigarettes, and the odd explosive compound. (Yes, I made my own gunpowder at age 14, and it was very successful!)

[Old Koreelah]

47 minutes ago, onetrack said:

Nope, never heard of the match head stunt. I must have had a less-exciting childhood. We only experimented with cigarettes, and the odd explosive compound. (Yes, I made my own gunpowder at age 14, and it was very successful!)

So did I. Lots of exciting chemicals could be had by mail order. Instructions for making explosive stuff were freely available, making up for my total lack of chemical knowledge. Our neighbours recall many of my experiments. One reached hundreds of feet; another exploded on the pad, removing much of my hair.

[old man emu]

A box of matches; two bolts; one nut.

Scrap the stuff off the match heads.

Screw the nut onto one bolt by a couple of threads to make a "container"

Fill the container with the scrapped stuff, leaving enough thread to start the other bolt into the nut.

Screw the bolts together to compress the filling.

Throw it, bolt first onto a concrete floor.

BOOM! Trajectory unknown.

[Marty_d]

17 hours ago, onetrack said:

 cause your death, is rather unclear.

It's spelled "nuclear"

[Old Koreelah]

3 hours ago, old man emu said:

A box of matches; two bolts; one nut.

Scrap the stuff off the match heads.

Screw the nut onto one bolt by a couple of threads to make a "container"

Fill the container with the scrapped stuff, leaving enough thread to start the other bolt into the nut.

Screw the bolts together to compress the filling.

Throw it, bolt first onto a concrete floor.

BOOM! Trajectory unknown.

That post might attract the attention of the Feds!

[old man emu]

Don't worry, the only terror it caused was when we realised that a bolt flying about like that "could put your eye out".

[facthunter]

You could "Keep an eye out" for the police.  Nev

[spacesailor]

Bu the easiest bangers to make !,  needed only three ingredients. 

We found this out when the. English government took away cracker night .

Silly buggers , 

They say it's for safety  .

Not so many missing fingers or eyes .

 

But !  making ' nitroglycerine ' is so easy . a little bit ( teaspoon ) sulphuric acid the same with nitric acid . Keep cool while  stirring. 

Then add a tiny amount of fulmate of mercury. 

Best bangers you could ask for .

spacesailor

 

[onetrack]

You blokes are going to have Federal Police knocking on your door soon, if you keep revealing your recipes!

[nomadpete]

I tried that, and the simple version - nitric acid on cotton wool.

 

Alas by then I couldn't buy nitric acid!

 

It was so disappointing.

 

But back then, the chemist shop still sold sulphur, and potassium nitrate. Or sulphur and potassium chlorate.

 

I suspect they still sell glycerine and condies crystals (potassium permangamate).

 

It was a lot of fun playing with reactive chemistry in my childhood days

Edited May 11, 2023 by nomadpete

[old man emu]

13 hours ago, nomadpete said:

condies crystals

Geez! A dehydrated condom!

[Marty_d]

1 hour ago, old man emu said:

Geez! A dehydrated condom!

Maybe they're talking about the contents...