# Radium Paint



## AaronC

Hi All.

I know there are a lot of vintage military watch collectors here. I'm curious how they feel about the radium paint found on older vintage watches.

I've read that this stuff is highly radioactive and dangerous, and I've also seen people buy these without seeming to care much about this. Do collectors replace the paint for safety reasons? Altering a perfectly good vintage dial seems a bit sacrilegious to me.

So what's the scoop about how to deal (or not deal) with radium paint?

Aaron


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## Watch-nut

If the watch is correctly sealed there is very little danger, however if you are going to be opening the watch, touching the dial then it is a slightly different ball game. To be honest as long as care around these types of watches are exercised i cant see the need to have anything done to the dial, of course you should notify your watch maker when sending it in for service.


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## AaronC

Watch-nut said:


> If the watch is correctly sealed there is very little danger, however if you are going to be opening the watch, touching the dial then it is a slightly different ball game. To be honest as long as care around these types of watches are exercised i cant see the need to have anything done to the dial, of course you should notify your watch maker when sending it in for service.


So is it the paint dust that's dangerous, like asbestos which only really hurts you when you inhale it? And is the problem inhillation, ingestion, or something else?

Or is it the radiation from it, which should affect you whether the radium is encased or not? If proximity is the issue, I don't see how keeping the radium encased would help.

Aaron


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## Watch-nut

The only real danger with radium paint is when attempts are made to remove it. Some authorities say that even removing a watch dial could result in breathing any accumulation of radon gas or radioactive dust that has come free. Scraping it off with a knife blade and letting the pieces get all over could result in later ingesting some and then it could be a health hazard for you, your family and pets

As for wearing the watch. The level of contamination likey from one singledial may actually register with very very sensitive instruments but is really no health risk of any kind.


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## AaronC

Watch-nut said:


> The only real danger with radium paint is when attempts are made to remove it. Some authorities say that even removing a watch dial could result in breathing any accumulation of radon gas or radioactive dust that has come free. Scraping it off with a knife blade and letting the pieces get all over could result in later ingesting some and then it could be a health hazard for you, your family and pets
> 
> As for wearing the watch. The level of contamination likey from one singledial may actually register with very very sensitive instruments but is really no health risk of any kind.


Thanks.

So it seems that these watches are only dangerous for the tinkerer, or for the watchmaker you hire to do your tinkering for you.

Aaron


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## William_Wilson

Radium is not necessarily safe to the watch wearer over extended periods of exposure. It emits alpha, beta and gamma rays. If a sufficient quality and quantity is used on a watch, the gamma rays can penetrate the case and crystal and be harmful over time. Don't wear the watch all of the time. What has been said about not opening a radium watch is of course quite true.

Do a search for radium on the forum, there are several threads covering it.

Later,

William


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## jnash

William_Wilson said:


> Radium is not necessarily safe to the watch wearer over extended periods of exposure. It emits alpha, beta and gamma rays. If a sufficient quality and quantity is used on a watch, the gamma rays can penetrate the case and crystal and be harmful over time. Don't wear the watch all of the time. What has been said about not opening a radium watch is of course quite true.
> 
> Do a search for radium on the forum, there are several threads covering it.
> 
> Later,
> 
> William


just for what its worth, when my panerai was sent back to italy, they wanted to replace the tritium with newer luminem as it was dissolving away.

would kill the value, also if they open, they are not allowed to send it back to the UK!

sucks!

Jonathan


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## harryblakes7

Scary...... i suppose this also applies to vintage 8 day bedside timepieces?? eeeerrr..... :shout:


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## William_Wilson

jnash said:


> William_Wilson said:
> 
> 
> 
> Radium is not necessarily safe to the watch wearer over extended periods of exposure. It emits alpha, beta and gamma rays. If a sufficient quality and quantity is used on a watch, the gamma rays can penetrate the case and crystal and be harmful over time. Don't wear the watch all of the time. What has been said about not opening a radium watch is of course quite true.
> 
> Do a search for radium on the forum, there are several threads covering it.
> 
> Later,
> 
> William
> 
> 
> 
> just for what its worth, when my panerai was sent back to italy, they wanted to replace the tritium with newer luminem as it was dissolving away.
> 
> would kill the value, also if they open, they are not allowed to send it back to the UK!
> 
> sucks!
> 
> Jonathan
Click to expand...

That's interesting. Exactly who prevents them from sending it back to the U.K.? Tritium has a short half life of approximately 12 1/2 years and emits weak beta particles. Radium on the other hand has a half life of 1600 years and emits alpha, beta and gamma (this is a simplification but makes the point). I wonder what the perceived hazard is in shipping old tritium?

Later,

William


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## Guest

just out of curiosity when did the use of this paint end ?


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## William_Wilson

Sofaking said:


> just out of curiosity when did the use of this paint end ?


Around the late 50's - early 60's. Tritium was then used because of it's safer emisions and shorter half life.

Later,

William


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## Guest

William_Wilson said:


> Sofaking said:
> 
> 
> 
> just out of curiosity when did the use of this paint end ?
> 
> 
> 
> Around the late 50's - early 60's. Tritium was then used because of it's safer emisions and shorter half life.
> 
> Later,
> 
> William
Click to expand...

thanks


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## Steve66

How can you tell if a watch has radium or tritium?

What is the difference?


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## William_Wilson

The glow from tritium is quite limited and you need it to be very dark to see it, even with the tubes. Tritium lume turns brown over time. Tritium dials will have "T SWISS T", a "T" in a circle, an "H3" or something like "T<25" on the dial.

Radium glows very brightly. The old radium watches look like the dials and hands have been cooked, because the gamma radiation has caused the luminous pigment's binders to decay. Sometimes the dials show burn marks in the area where the hands have been resting.

Oh, I forgot to mention, a Geiger counter would do the trick.









Later,

William


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## Steve66

Is this 1942/43 Longines a radium watch :shocking: ?


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## William_Wilson

I'm not an expert on old Longines watches, but it does look that way. In the 30's, 40's and early 50's radium was pretty much all they used for lume. Don't wear it 24 hours a day or sleep with it right next to you. Radium's half life is over 1600 years, so if it is radium, it is still "hot".

Later,

William


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## Steve66

Thanks William.

I had no idea that a watch could be bad for your health


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## William_Wilson

Intensity of radiation varied with make, model and period of manufacture. Reducing exposure time is a simple precaution. Another thing, until you can verify if it is or isn't a source of radiation, don't open the case yourself. Leave that to a pro.

Later,

William


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## Geronimo

Adrian v d Meijden wrote an excellen article for the Horological Journal on this subject, to be viewed here; Radioactivity in Military watches


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## tixntox

So this is what gave me the headache!










:shocking:

Is it the watch or the geiger counter ticking? ..... and where's that missing lume from the minute hand?



Mike


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## harryblakes7

Crumbs Mike!! :jawdrop: I could probably find you in a football crowd, as the only person who is "glowing"

Am sure you'll be ok, just go careful, wear a good quality dustmask and scrub those fingernails!!!


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## gaz64

Lifted from http://www.evs.anl.gov/pub/doc/Radium.pdf

*What Happens to It in the Body? *

*
Radium can be taken into the body by eating food, drinking water, or breathing air.*

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*

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Most of the radium taken in by ingestion (about 80%) will promptly leave the body in feces. The remaining 20% enters the bloodstream and is carried to all parts of the body. Inhaled radium can remain in the lungs for several months and will gradually enter the bloodstream and be carried throughout the body. The metabolic behavior of radium in the body is similar to that of calcium. *

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*

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For this reason, an appreciable fraction is preferentially deposited in bone and teeth. The amount in bone decreases with time from the exposure, generally dropping below 10% in a few months to 1% and less in a few years. Release from the bone is slow, so a portion of inhaled and ingested radium will remain in the bones throughout a personâ€™s lifetime.*

*
*

*
What Are the Primary Health Effects? *

*
Radium poses an external as well as an internal health hazard. The strong external gamma radiation associated with several short-lived decay products of radium-226 and radium-228 makes external exposure a concern, and shielding is often needed to handle waste and other materials containing large concentrations of these radionuclides. The majority of epidemiological data on the health effects of radium-226 and radium-228 in humans comes*

*
from studies of radium dial painters, radium chemists, and technicians exposed through medical procedures in the early 1900s. These studies, as well as studies on experimental animals, indicate that chronic exposure to radium can induce bone sarcomas.*

*
*

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The minimum latency period is seven years after the first exposure, but tumors can continue to appear throughout a lifetime. The inhalation risk is associated primarily with radium decay products, i.e., radon and its short-lived daughters. Each of the two radium isotopes decays into a gaseous radon isotope. Radon-222 is a short-lived decay product of radium-226, and radon-220 is a short-lived decay product of radium-228. The primary hazard associated with radon arises from the inhalation of its short-lived decay products, which are charged ions that readily attach to dust particles. These particles can be inhaled into the lungs and deposited on the mucous lining of the respiratory tract. Unattached decay products tend to be inhaled deeper into the lungs where the residence time is longer. When alpha particles are then emitted within the lung, the cells lining the airways can be damaged, potentially leading to lung cancer over time.*

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*

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What Is the Risk?*

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Lifetime cancer mortality risk coefficients have been calculated for nearly all radionuclides, including radium (see box at right). The ingestion and*

*
inhalation coefficients for radium-226 and radium-228 are generally comparable. While ingestion is the most common means of radium entry into the body, risk coefficients for that exposure route are lower than for inhalation. Similar to other radionuclides, the risk coefficients for tap water are about 75% of those shown for dietary ingestion.*

*
*

*
In addition to risks from internal exposures, a risk from external gamma exposure is associated with these two isotopes. Using the external gamma risk coefficients to estimate lifetime cancer mortality risks, if it is assumed that 100,000 persons were continuously exposed to a thick layer of soil with an initial average concentration of 1 pCi/g, then 40 of these 100,000 people would be predicted to incur a fatal cancer if the soil contained radium-226, and 7 if it contained radium-228. (This is in comparison to the 20,000 people from the group predicted to die of cancer from all other causes per the U.S. average.) These risks are associated with the gamma rays emitted by various decay products of these two radium isotopes.*

A bit dray but it does reinforce that radium is scary stuff


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## harryblakes7

Very interesting Gaz, thanks for posting........

Hey Mike, in gambling terms i "see" your Elgin Watch and raise you with my large JW Benson


















Anyone else better that?


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## tall_tim

William_Wilson said:


> jnash said:
> 
> 
> 
> 
> 
> William_Wilson said:
> 
> 
> 
> Radium is not necessarily safe to the watch wearer over extended periods of exposure. It emits alpha, beta and gamma rays. If a sufficient quality and quantity is used on a watch, the gamma rays can penetrate the case and crystal and be harmful over time. Don't wear the watch all of the time. What has been said about not opening a radium watch is of course quite true.
> 
> Do a search for radium on the forum, there are several threads covering it.
> 
> Later,
> 
> William
> 
> 
> 
> just for what its worth, when my panerai was sent back to italy, they wanted to replace the tritium with newer luminem as it was dissolving away.
> 
> would kill the value, also if they open, they are not allowed to send it back to the UK!
> 
> sucks!
> 
> Jonathan
> 
> Click to expand...
> 
> That's interesting. Exactly who prevents them from sending it back to the U.K.? Tritium has a short half life of approximately 12 1/2 years and emits weak beta particles. Radium on the other hand has a half life of 1600 years and emits alpha, beta and gamma (this is a simplification but makes the point). I wonder what the perceived hazard is in shipping old tritium?
> 
> Later,
> 
> William
Click to expand...

We get notifications every day at work of radioactive material being shipped into and out of the country, via ship and plane. Some of this material is extremely radioactive too, with short half life (days/weeks). I can't see why a watch would be stopped from travel, providing the correct paperwork is in place.


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## Geronimo

harryblakes7 said:


> Very interesting Gaz, thanks for posting........
> 
> Hey Mike, in gambling terms i "see" your Elgin Watch and raise you with my large JW Benson
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Anyone else better that?


In gambling terms I see you and raise with a "full house" The dirty dozen :tongue2:


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## William_Wilson

tixntox said:


>





harryblakes7 said:


>


I can't tell very well from the photos, do either of you have dial burn in, where the hands have sat while not running? In both of those watches, the lume is well cooked by the radium.

Later,

William


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