Kathleen - This presentation is first class in every respect. Well organized, interesting, great exhibits, accurate and very professionally delivered. Thank you!

What a fascinating, if slightly macabre in parts, but ultimately highly highly informative presentation. Loved it. Thank you for sharing. Best regards, TGV

Good overal presentation. I disagree with the statement “Gamma rays are the most dangerous”. Gamma rays pass through matter more easily than alpha particles (Alpha particles are stopped by the skin) however, if alpha particles make it to the soft tissue of the body, they cause way more harm to the DNA. That’s why radon gas is dangerous; it decays into polonium-218 and polonium-214 (and others). Po-218 and Po-214 emit alpha particles in the lungs soft tissue. Watchmakers ought to be very careful opening Radium-lumed watches. I personally eschew them, and find zero charm or value in the radium-induced patina. Also, at higher altitudes, radiation exposure is not higher because you’re closer to the sun, but you are less shielded from cosmic rays (by atmospheric particles).

I watched your presentation with great interest. Thank you very much for the useful information. I noticed that your Tudor Oyster watch, according to the Geiger counter readings, resembles a mini Chernobyl. 350 μSv/h is the highest radiation level I have encountered in wristwatches. I always believed that, among those that have survived to this day, the most radioactive wristwatch was the 191-ЧС diver's watch produced by the Zlatoust Watch Factory, USSR, in the 1950s-60s, with a radiation level of 10,000 μR/h or 100 μSv/h. The second most radioactive watch is the very rare Beobachtungsuhren (B-Uhr), worn by German pilots during World War II, with a radiation level of 8,000 μR/h or 80 μSv/h. As you know, a lethal dose of radiation is considered to be 7,000-10,000 μSv/h. The size of these watches is about 55 mm. They are significantly larger than your watch, and consequently, they contained a larger amount of radium-226. This means that if you are exposed to your watch for at least 10 minutes per day on the side of the dial, it would take about 120-150 days to reach the maximum permissible dose of radiation. I sincerely believe that your device might have shown erroneous results.

Thank you for this horologist's view of radium. Nice talk!

Great Lecture, very informative. I have obsessively studied Radium Dials, and found information in this lecture I didn’t know. One thing to add. They have done recent studies recently that show that a lot of the danger is the Radon gas they give off, and that significant amounts of radon can build up with a small collection. Also the thing that makes me cringe sometimes is the amount of damaged radium dial stuff that is left, that falls in the hands of people who aren’t collectors. People on eBay selling them, with no idea they have to be careful at all, and people doing things like making radium dials into jewelry, that people handle and wear. I usually won’t sell a watch without bringing up that it does in fact contain radium. Also, I agree that a Geiger counter is a good thing to have. From testing a lot of watches with a Geiger counter, something that varied a lot that I found was the amount of radioactivity in different mixtures used by different companies at different time periods. Some watches can be not very hot at all, and some can be *very* hot, even within the same manufacturer. Also, the crystal does block a lot, but on the other hand, I have had really hot watches without crystals, where you can pick up a reading pretty far away from the watch. Its hard to not go to either extremes, some people won’t go near them, and some people don’t worry about it at all, I think the answer is somewhere in the middle of the two. I personally don’t collect them, (which has broken my heart several times when I found an amazing different watch with radium), but I have a collection of over 300 vintage watches, and deal with watches a lot. In any case, I really enjoyed the lecture. From the article: “Radium decays to radioactive radon gas, which is readily inhaled and will in sufficient doses significantly increase the risk of lung cancer. Radon is the second leading cause of lung cancer in the USA after cigarette smoking; the EPA estimates that radon is responsible for about 21,000 cancer deaths annually. The study found that 30 radium dial watches, when kept in a poorly ventilated space the size of "a typical bedroom” produced radon levels a whopping 134 times the recommended maximum safe level. In addition the study says, " ... three of the watches in poor condition gave rise individually to radon concentrations - when kept in the same poorly ventilated room - well in excess of the threshold where Public Health England would recommend remediation." www.hodinkee.com/articles/new-report-shows-radium-dials-might-pose-serious-danger

Safety comments for watchmakers/restorers start about 1:05:45

Superb tutorial, thank you and warm regards from the UK.

Watched every minute of this, sooooo informative. Loved it.

Wow. Wonderful presentation.

Them you so much. Super detailed and informative talk.

This is great. Thanks!

The usual point that radioactive materials aren't that dangerous is in some part misleading. This is only true if the material is completely contained. If you accidentally ingest a radioactive material-such as radioactive dust if a watch containing tritium/radium were to fall on the floor and break-that radioactive dust will be everywhere in the room, and it will lodge in your lungs, emitting radiation in your lung tissues 24/7, for the rest of your life. Similarly if you touch a small quantity of a concentrated radioactive material, and then eat an apple or something.

An excellent lecture!

I'm 78 and have been wearing my radium watch for many years and have had no problems as when the arm my watch was on dropped off I have the other arm to wear it on. 😊

Radium began being applied by watchmakers in 1917 with both men and woman wearing these watches until the Swiss agreeded to switch to lower emitting Tritium in the early 1960's. There is really no way to directly correlate certain cancers such as leukemia to this period. As a vintage collector my concern would be with falling a sleep with the watch on and inadvertently placing the crystal against the face especially eyes for extended periods of time. I'd highly recommend removing a known Radium watch from the wrist before sleep

A fascinating watch (excuse the pun) so I thoroughly enjoyed the video...thanks. Within the last couple of years I've become very interested in all things radiological, including the RADIUM compound lumes found on vintage watches, clocks, compasses & aircraft instruments etc. Many other household items contain or contained radioactive materials too, like...modern smoke detectors (Americium 241), vintage camera lenses (Thorium 232), vintage glass & ceramics (Uranium 238 & depleted Uranium), vintage EXIT signs (Tritium), Quantum pendants (Thorium 232), Vintage Dutch tiles (Uranium 238). Even many lead crystal pieces may have elevated above background levels (slightly) of emissions caused by the isotope Pb 210 (lead) trace elements. However, a few gripes if I may though: I don't think I've ever come across a background "dose rate" as low as 0.096uSv/h before, especially with a mica "pancake" sensored GM counter...@45:42 I've absolutely never come across a radium dialled watch that has an intact crystal & a dose rate as high as 320uSv/h before either... @49:06. The highest I've measured with a Radiascan 701A mica "pancake" sensored GM counter is around 50uSv/h with a fully intact crystal. So I can only think that the GM counter used in this presentation is WAY out of calibration OR the OUTSIDE of the watch at the crystal has been heavily contaminated with the loose lume particles containing RADIUM 226. No alpha particles should be able to penetrate an intact crystal, with even some lower energy beta particles being stopped by this barrier as well. Only higher energy beta will get through along with all of the gamma rays of course. So, an argument could be made for using a cheaper type of GM counter that can detect beta & gamma ionising radiation but not alpha particles & which would be very useful for detecting the presence of RADIUM on any watch/clock etc etc dials. You'll find that Tritium tubes found on some watches etc DO emit "bremstrahlung", which is similar to penetrating X-rays & which is caused by the braking effect of electrons. However, it is only slightly above background, say 0.30 uSv/h, where normal background, where I live is around 0.16uSv/h, when the GM counter is held against the Tritium tube that I've tested...BUT it IS detectable. Much safer than the Radium compound though as that becomes FRIABLE with ageing, which is why the watch maker/repairer must be careful. You've only got to check out youtube to see the number of people totally unaware of the presence, let alone the hazards of Radium compound lumes. So, know about it & buy a cheap geiger muller counter, then use a wet process to remove old lume, if you have to & do it well away from anyone else.

Nice lecture well done.

Absolutely fascinating! Thank you so much for sharing this!

Very interesting video. Anyone walking in to this lecture could be forgiven in thinking this was a talk in nuclear energy as opposed to watches.

How can I get the slides for this lecture?

I need to comment this. I understand people want the paint on their watch, but a lot of us DON'T. there needs to be a way for us to safely remove the paint and a whole thorough explanation for what to do. I've been reading, googling, and looking at all resources. and all of them don't explain what the residual radiation that is still left on the watch is it still contaminated? is the watch metal still radioactive? the glass the cleaned dials? I don't know but an official answer would be so nice! (if this is explained already please excuse me. (i just got into clock making/ tinkering recently)

Great video….lots of good information. A couple of points: Increased radiation exposure while flying has nothing to do with “being closer to the sun”. We fly at about 6 miles above the earth’s surface, but the earth’s distance to the sun varies by about 3 million miles between closest and furthest approach during the year. Those 6 miles at flight altitude are a fraction of the annual 3 million mile orbital variance; however, when flying we have 6 miles less atmosphere to block solar radiation and other cosmic rays. So, it’s the reduction in protective atmosphere that allows for increased radiation exposure during flight. Regarding the 111,000 cpm radiation from the watch face, basically none of that is alpha particle emission due to the glass bezel. If you were to remove the bezel and take a reading, you’d easily see the cpm double. The back of the watch is radiating mostly gamma with some, but not much, beta, and other radiation (again, no alpha). As an example, I have WW2 British military compass with an unprotected radium sighting strip on the mirror that puts out in excess of 216,000 cpm on my less than very sensitive meter, which drops down to 85,000 when I use an alpha filter. Regarding lead, the thickness of lead is important in stopping gamma, and, even then, sometimes some gamma manages to get through lead. The same for beta and aluminum. But, yes, in general most beta is stopped by aluminum of some realistic thickness and most gamma is stopped by lead of some reasonable thickness. It’s possible that sample size may also be a factor, but I’m not an expert in this area, so I do not know. Regarding popping a watch into a box lined with aluminum foil and a geiger counter not seeing anything, I seriously doubt that, as more likely than not there will still be gamma emissions that will pass through the foil and register with a geiger counter. Again, in the case of my compass, the aluminum filter and the lead filter still allowed radiation to pass, albeit at significantly reduced levels, but still clearly present. Regarding counts versus dosage, you are correct that meters need to be calibrated for the particular source they are intended to measure, which is why counts per minute is generally a better comparison than dosage measurements. Something reading 500,000 cpm with a lower dosage reading than a sample measuring 100,000 cpm with a higher dosage reading just means the meter is not calibrated for the higher cpm source. Never dismiss high cpm because your dosage value appears relatively low.

Enjoyed it. Thank You. I am an avid collector of these watches.

Love all these lectures and hate to criticise but I feel this one is a little loose when mentioning blowing radium dust away. To blow out, one first has to breathe in, which is dangerous if a lens has not been removed from say a Rolex Submariner for 50 years or more. And then where will the dust land and collect?

We need a follow up episode I think. This was a brilliant lecture and I learned a lot I have to say. With that said, I can’t wrap my head around what to do or not with the radium watches I own. These are lovely timepieces charged with tone of history and… radioactivity… I wish I had a clearer guidance about what to do with them and what to be worried about. During my early years as a watch enthusiast I have clearly not been careful while handling vintages watches and clocks that had radium! This topic is vital and not talked about enough at all in my opinion. One part of me thinks that even as passionate I am about watches the hobby is not worth the risks. On the other hand, if handled carefully this radium timepieces shouldn’t be dangerous. For now I stopped buying radium lined watches or clocks. I carefully packed all the watch parts such as dials, hands showing some local high levels of radioactivity. My primary concern is to break a crystal of a radium watch while wearing it! My god this would be bad! Any input are welcome! Stay safe watch people!

I learned so much from watching this, thank you. So if Radium 226 is alpha, is it fairly useless in buying consumer grade geiger counters from places like Amazon that mainly detect beta, gamma and x-ray? If you are going to get one, is it your suggestion that they accurately detect alpha, beta, and gamma?

I came across a lot of watch repairmen in the local market through my collection of old watches from my childhood [and I am now close to sixty years of age] and who dealt with antique watches for decades and without reservation and without protection from tritium or radium and some of them are still old and some of them died after a long life And they were in good health, and I did not see or hear that any of them had cancer, and I think that humans have the ability to get rid of and adapt to bad and negative influences.

Very interesting but there are a few things you got wrong and I would like to point out: - Radium emits all three types of radiation: Alpha, Beta and Gamma, Not just Alpha; - The radiation your Geiger counter is detecting is only Beta and Gamma, all the Alpha particles are being Stopped by the glass or crystal of the watch, doesn't matter if your Geiger counter has a pancake mica window in this case; - You said the most dangerous kind of radiation is Gamma because it's harder to stop but it's actually the opposite, the fact that it goes through your body makes it safer than Alpha and Beta because your are not interacting much with it. On the other hand, Alpha is considered the most dangerous type of radiation because your body absorbs all the emitted energy when you are in it's proximity; - It's not true that skin alone is sufficient to protect your body from Alpha radiation as it can easily penetrate in the dividing layer of cells causing skin cancer.

Another question would be... What would you consider required equipment when handling these kinds of watches? I mean, regular latex gloves and facemask (N95)? It is good to hear that the radiation levels are not that high to damage someone in a short period, but there are lots of people opening the cases that are just doing it as a hobby without even knowing these things. How volatile the radium dust is and the radon? Just being in a well ventilated place will fix it? Not sure... Not trying to worry everybody here but you can see in the comments of this video that at least 3 out of 50 comments are worried as they handle a clock with not enough care.

Smart Lady

I dint really want an hour of history. Anyone have a quick summary...do we have to worry about radium in watches?

6:15 for the actual start

Temanku profesi sebagai perbaikan jam juga meninggal dengan gejala yg sama dengan radium girls. Akibat ketidak adaan informasi yg benar tentang radioaktif nuklir.

I have vintage chronograph from 1970s with “t Swiss made t” on dial. Is it 100% safe to wear?

Radium watches = blood watches. I recommend you do a follow-up meeting with cancer victims, particularly people exposed to radiation, as well as cancer specialists.

Does the radiation emit as strongly from the back of the watch?

Great video!!! I sell these on eBay. This helps

This audience doesn't seem to have any shock reactions.

shit i just opened the case back of a 40s Longines that had radium hands .i was looking really closely at the ingravings of the inside of watch back ...did i just probably inhale some particles ??? im worried now

I am not convinced that there is any harm in waring a wristwatch that has radium painted dials.

So can I still wear my Rolex 6466 radium dial ? I love the thing

KZfaq: Old Radium watch

All that Tritium in the Fukushima water. Hmm.

Kathleen mentioned and showed at 58:54 a Radex meter that, to the best of her knowledge, only measured gamma radiation (up to 9.99). She took a measurement from the watch that she was wearing, and it indicated it's maximum capable measurement of 9.99 for gamma radiation (the actual measurement of gamma could well be much higher than 9.99), which as she explained was the most dangerous and will pass through the body and metal (but not lead). If that is the case, then isn't she exposing herself to gamma radiation by wearing that watch, which could be quite dangerous?

This tells you how to trust your medical professionals. 😂 This tells you how to turn a newly found material into a lucrative business. 🤣

The girls that painted watches with radium died horrible deaths. There is another lecture about it.

I get it you should be careful, especially when opening, but people wore these watches every day for many decades, and I’m not aware of any correlation to increased cancer risk. It seems to me the real risk of cancer from a watch would be fairly small unless you were working on them every day. Hell, even the old time watchmakers that worked on these for decades. Has there ever been a study of watchmakers to see if they suffered cancer at a higher rate than the general public?

radium on wrist watch is dangerous only if you breathe in that dust of a dial and do it no more than few times,but to do that you gotta be an idiot , in this case collect a chewing gum stickers.

Last time i checked, there is no such thing as "tritium paint" because tritium is a gas and can't be mixed with any liquids...

ermm

There is no reason to wear a radioactive watch, unless your trying to be that fringe person

Um... Um.. and ummmmm..... 🤮🤮🤮🤮

Spoiler: she got cancer.

Just don't wear it. There should a legal requirement to inform about radioactive watches prior to selling them.