Mil-Spec Radium Dial Panel Meters 

I suspect that the heavy cases on the meters had a lot more to do with protecting the instrument than with protecting the operator. That kind of thinking didn't really become common until decades after those meters were built... Fascinating stuff. Thanks Fran!

Even if you have a gamma/ x-ray counter that is not directly sensitive to alpha/beta you'll pick up a little x-ray 'bremsstrahlung' from the alpha/beta particles impinging on the window of the counter.

I used to live near the UK National Physical Laboratory. They luminised instruments during WWII, and also were the national centre for radium sources for medical treatment. About 20 years ago that area of the site was demolished and given over to housing. They had to dig out about 6 feet of earth, then put down an impermeable membrane because of the contamination.

I really like old dials and meters.

A lot of meters are painted with things other than Radium, like mesothorium, which is insanely radioactive, with a half-life of about 6 years. So it's likely those dials, if they are 60 years old, will be down to about 2^-10 of their initial radioactivity, or just one part per thousand of the original activity!

In the suburban Philadelphia area in a town called Lansdowne a professor processed Radium in his basement back years ago. The site became a major hazardous waste superfund cleanup site. I grew up about 1/4 mile away. The professor and many of his family have died of cancer.

The AN/PDR-27. I repaired so many of them while working as a technician for the US Government. I remember the Purple Rod used for testing them. Calibrating them behind lead panels was always scary business.

What's awesome is to realize, assuming natural Radium, those clicks represent a direct connection to the energy from the death of a star.

Awesome vid Fran, love these retro videos. According to a Department of Commerce Information Circular from 1930, the paint might contain "from 0.7 to 3 and even 4 milligrams of radium element to 100 grams of zinc sulfide.

I had one of those in high school! As I recall, it was 0 to 50 VDC ..it glowed dimly all night. It was connected to my homemade 12 volt selenium solar cell panel. Old orange " carnival glass" was slightly radioactive. We did radiographs with a 1930s orange plate and Tri-X pan sheet film in physics class. This was back in the mid '70s... I like those old school analog meters..I have a few old ones, but most " evaporated" over the years... Another cool video of old school stuff .

I had a physics professor bring over a fancy geiger-counter to check over my Collins R-392 military radio. It had a small barely glowing tuning meter. The counter showed 13 millirems/hr at 4 inches away. Pretty high, even it was probably about 8 half-lifes run down.

Wow, I haven't seen an AN/PDR-27 in years. Not since I was in the Navy.

These old instruments are works of art. One thinks to be able to recognize the quality by the care of the production. At that time, the appearance of an instrument was still very important.

I never knew that the phosphorus is what's actually glowing! Very fascinating!

That thought about how vintage tech has a lot of radium in it triggered my memory about the story of The Radioactive Boy Scout who managed to collect so much of in in his small shed that it was eventually declared a hazardous radioactive site and the cops had to call in the EPA to clean it up. His radioactive source wasn’t from vintage stuff though.. it was harvested from pilfered smoke alarms lol. What an idiot.

Thanks for the video on these. Love those old units.

Very Cool Fran! Thanks for sharing.

I love these films where you fix things up..

Hi Fran, 40yrs ago I watched someone restore those meters !! It's a real pain in the A-- !!! Because you need LOT'S of lead shielding and a positive pressure air mask !! The guy worked at Oak Ridge !

Wow! A real radium dial. Those are so wonderful. Dad's old radio had one... The one that sat less than a foot from his head in the headboard cabinet... Wow.

Great video, Fran!

There's a museum near me in Ottawa, IL that is dedicated to the radium girls. Sad, but interesting history.

Thanks! I was aware of this aspect of the two dials on my vintage US military short wave radio Collins R-390A/URR but had not found the explanation of it yet. I now get why these dials are taken out if the crystal shielding is damaged.

If you take a loupe, say 30X, and look at the radium phosphor in the dark, you’ll see little sparkles around each disintegration.

That's pretty cool. It seems like those would actually be fairly safe to use in a project. I'd probably use one in a home made Geiger counter just because it would amuse me.

I still have the Baby Ben alarm clock I bought in 1972. The phosphor has been nuked off over the years so there's is very little glow when hit with bright light then put in darkness. However, it still scintillates when your eyes get dark adapted and you can see the little sparkles when you look through a magnifier. We used to do this in physics class in the 1960's with an alpha source in a tube with attached magnifier. Later, the alpha source was taken away by school officials, but we still was playing with the spilled mercury found in the windowsill that oozed up from the woodwork that a student spilled several years before. Today, if a cracked old mercury thermometer is found in one of the old school cabinets, it is red alert!

Weston Meters were made in the UK and USA by Sangamo Weston, and the differences between the two are very minor but they have different model numbers. Some later models were made by other manufacturers under licence. The US company was founded in 1888 Springfield Illinois as a manufacturer of electrical measuring instruments with a factory in Newark NJ, with the UK company following on in Enfield Middlesex a year later. In 1954 the US company was bought out by Daystrom, then in 1962 Schlumberger took over Daystrom. In 1974 the Newark plant was shut down. In 1987 there were investigations going on over contamination of the surrounding land. Sangamo manufactured PCB-containing electrical capacitors there during 1955-74. Sangamo notified the US Environmental Protection Agency of its disposal of approximately 38,700 cubic yards of PCB waste on its plant site and an undetermined amount in seven satellite dumps, all in the Twelve-Mile Creek Basin. Solid, sludge, and liquid wastes were stored or disposed of in piles, landfills, and impoundments. How nice! Since then Sangamo-Weston has removed over 17,000 cubic yards of waste from past disposal areas on and off the plant property. How sad it should all end this way - I'm sure Edward would be turning in his grave if he knew.

I used to live near the National Physical Laboratory in Twickenham in the UK. They used to luminise instruments there for aircraft during WWII and after. They also were the supplier of radium for medical purposes. Later they wanted to build houses on that part of the site, they had to dig out to 2 metres deep and seal the land.

Crikey, I used to fix clocks when I was young, lots of them had dials & hands which “glowed”, but I’ll never know if any were *proper* radium ones... oh just remembered about the box of old panel meters stashed under my bench...might be time to get a geiger counter :-)

DON'T lick the paint brush Fran!

Pretty nifty dials! I've always loved leaded glass :)

another frantastic video. thanks for this video.

Very interesting video!

Very interesting. Thank you.

I really miss the radioactive painted dials. Especially on my watch.

Very interesting episode thanks! Reminds me of the scene in Dr No when Bond tests his geiger counter by putting it against his watch dial.

I love radium dials. I know "radioactivity is bad" and stuff… I'd probably wouldn't leave it in my pocket but a watch is fine and you could actually see it in the dark as opposed to whatever they use in watches now. Cause that new stuff doesn't glow what so ever.

Nice find

Thank you!

A great little video. Imagine all those people who were woken by alarm clocks which were dosing them in radiation all night. I still have my 1970s TIMEX childs watch I wore, with its glow in the dark hands and hour markers. I'm guessing it may still click a little, although it had a thickish glass front.

Great Video

I love that stuff!

Love the Green Glow of Radium

My Grandfather, I'm 62 btw, had a watch that glowed in the dark, but only the 12,3,6 and 9 had little rocks of yellow embedded in the points and the hands glowed brightly as they went by the rocks, and slowly dimmed as they were away from the rocks. He said he got it in Egypt, and that the rocks were Uranium, and the hands had some Zinc paste on them. The hands glowed a blue color and the 4 points a greenish light not as bright as the hands. Near the 3, there was a moon that changed size for the waxing and waning of the moon, and it glowed as well But I can't remember the color maybe a sort of yellow, there was a picture of the man in the moon or something like that on it. He did this trick where he held his watch up to another watch that had 'normal' radium paint on it, and the other watch would glow really brightly.

AH, The Warmth and Glow of Radiation..

I was told by My Jeweler that to some of the early watches and meters used polonium instead of radium because it was less expensive also I have a Korean war-era military Jeep (m38a1) and the speedo is radium lettered and still glows brightly to this day.

Very interesting, love it. Do these instruments really have the exactly same SN 175318?

tritium dials are kinda cool too

I've seen a lot of regular, panel meters at the surplus places I used to go to, but I've never seen a radium dial version. (or if I did, it was when I was young and didn't realize it.) Sadly, they are all out of business now. I should have taken every panel meter the last guy had, but I didn't. (but I've still got quite a few, and my dad has some as well)

There is an article I found that does mention specifics and goes into detail about the amount of radium in paint and goes into detail about the composition of them

Cool video, Fran! That said, the part I immediately went back and played again was the closing credits. What a fantastic groove! Is that on a record somewhere?

Very cool! I don't suppose you would consider parting with a few old meters? i need 3 for my transmitter 100ma full deflection or less not picky. I could make 50 ma work too. The ones i have are old and crappy, they stick sometimes and are not the same shape and size. Yeah i could get new ones but they're new, just a thought. I forgot about the haul from the uni years back....makes me think i've been watching you for quite a while now time does in fact fly by.

Really interesting video, thanks :-)

Excellent video! Was literally thinking 'that's lead crystal' just as you said it... It occurs to me the dimness may also be down to radium decay, as well as phosphor degradation., but I dunno what its half-life is.

Many years ago, my parents had some green glass bowls which turned out to be a bit radioactive. It seems they used to use uranium compounds to get the nice colour!

Beautiful meters Fran! God I love vintage meters. Doesn't the inverse square law only apply to an isotropic radiator? Surely a highly collimated beam doesn't behave this way. Unless I'm wrong of course. Haha. Thank you for the fun and VERY interesting vids Fran ~{:-]

Radium emits a weak 186 keV gamma but it's daughter's have much higher and more penetrating Gamma Ray's. Namely Lead ²¹⁴ and Bismuth ²¹⁴ this was from HPS.org As you know, both 214Bi and 214Pb emit measurable gamma rays, and both can be useful in the indirect determination of 226Ra, a precursor in the decay chain that produces the lead and bismuth progeny. The 214Pb emits lower-energy photons than does the 214Bi, the three most abundant gamma rays from the lead being at 242 keV (7.43 percent), 295 keV (19.3 percent), and 352 keV (37.6 percent). The dominant gamma rays from 214Bi are more in number and higher in energy than the lead gamma rays; the range of useful energies is from about 600 keV to about 2.5 MeV. The bismuth gamma ray of highest yield is at 609 keV (46.1 percent); there is a gamma ray at 1.12 MeV (15.1 percent) and one at 1.765 MeV (15.4 percent). The others have individual yields no higher than about 5 percent.

Have you done a video about your Geiger counter?

Very cool

Also don't forget that the radium itself decays; the isotope with the longest halftime is 1600 years, but the runner-up is only 5.75 years. After a few decades quite a bit of radium may be gone.

I DO NOT think these contain Ra-226. These were probably re-lumed or never had radium. Not all old instruments contain radium, military or not. For military instruments, if the paint isn't tan or doesn't look "burnt", it's probably not radium. I would do a timed count, for about 10 minutes: One with the meters as close to the G-M tube window as possible, and the other with the meters out of the area with the window open for background. Repeat this for better results. If there is no change, than it wouldn't be radium, since some of the Ra-226 daughters emit very high energy gamma rays, e.g. bismuth-214, which easily penetrate glass. I have A LOT of various Ra-226 sources, and all of my Geiger-Müller counters can easily detect them, some through concrete and lead bricks.

And to think that thousands had these clock radio right next to them while they slept! Surprised they didn't glow after they woke up!

Awesome sauce😆

Yes, Fran. More like this. Ancient electronics porn. The music at the end is genius. I could see it getting old at some point, but right now, it's great.

Don't forget the story of the radium girls

Love your videos wish I could afford to get on patreon with you

Pretty cool. I'm also curious about that geiger counter, it's obviously not the typical old Civil Defense relic. Looks like a Fallout prop!

Be careful not to open or break the glass/celluloid cover on old clocks and watches. Inhaling or ingesting the dust from that paint is lethal. I got a ww2 pocket watch recently, and didn't even think about radium until I'd had the back off and looked inside... 😓😵😱

thank you good imfo.

I have an old Western Meter, it is a model 301, it weighs about 240 Gram's. But mine has a silver like face on it.

radium should still be used safely of course it make some of the best glow in the dark stuff

If i replace the phosphors on my R390 meters will they work again ?

I remember back in the 1950s you could buy tins of Humbrol luminous paint and as far as I know it was radioactive. The withdrew it in the 1960s because kids used suck the brushes after painting here glow in the dark model skeleton kits.

But is it really Ra-226? There is little information about that, but Ra-228, Th-228 and Sr-90 were being used, too.

You have to be careful when you buy surplus stuff. Vacuum tubes sometimes contain Thorium.

There is one thing you didn't mention. What were these gauges used for? There is no indication of measurement on them. Just a graduate from 0 to 100. Amps? Watts? Voltage? Temperature? The angle of the dangle? What?

I think a tear down would be informative to see what indestructo work had been done on these.

Now could you paint over the numbers with fresh phosphorous and get it to glow again And does tritium vials have less emitted radiation

I have not been able to fully shield the Gamma rays from Radium/Radon daughter's without having to use very thick lead

So Fran, at 1 foot what is the hazard? Is it dangerous at one foot?

Are those painted with Undark?

They wouldn't present a serious risk by being opened given the comparatively limited radioactivity of radium paint, but even so, I wouldn't open them just from the point of preservation.

Might have just been well made for durability not to protect the users .

What is the model of that detector?

Well, I'm not sure you have radium here. There are some contradictions in the observations that raised questions: your GC doesn't peak any gamma but the dial are still glowing reasonably, strange? Even if Ra226 half life is 1600y, it has a characteristic gamma line at 186keV, and Bi214, Pb214 (decay products) have also several gamma lines that should render your GC crazy... And gamma will never be blocked by the watch glass. Also, the luminous paint seems not degraded: if it was ZnS (copper dopped zinc sulfide), the molecule should be broken by alpha particles comming from Ra decay, rendering the paint almost inefficient after several decades... I have some needles with radium paint, quite old, they all exhibit the same appearance: heterogeneous remaining and faint luminescent (some spots more visible), not reacting to normal light, but still a strong reaction of my Geiger counter. I tried also to find some specs about these meters, but found nothing regarding luminous paint. It could be interesting to make a gamma spectrum to get a confirmation. If you can. Another simple test would be to check the remaining luminescent after 48h completely in the dark.

Is the shield on the end the wrong way round? it shields the gamma tube while open..

Um, when did radium exit the retail sphere? I'm sure my first wristwatch in the Sixties glowed for hours after eliminating any light source. Also, no need to capitalise the elements, folks, unless you're capitalising the first letter of every word in a sentence for... I don't know what for.

What did they measure?

By having them sealed, wouldn't they be protecting not just the operators but also the instruments themselves?

are old darkroom timers hot too?

i would have expected those to be brighter

Nice vintage display... "dark mode" isn't just a new feature for cellphones.

That detector wand looks like a lightsber ...if Star Wars had been made in the 1940's

I could use one of these to detect all the toxic relationships in my life.

Are the meters still working? 100 Amp full scale?

Now you need to make something that uses them...

I'm sure to deflect lawsuits those employers destroyed the recipes of their radioactive paints.....

Another reason not to open them is possible accumulation of radon gas inside, assuming they are really well sealed.

Is the fluorescence green uranium glass radioactive?

I worked for a company that had a bunch of this. Some people died of cancer