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Discussion Starter · #1 ·
How long does it take for a dial to have strong radium burns to the dial where the hands have sat for a long time? Any ideas?
 

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Exactly 22 years 4 months and 5 days..........:-d:-d:-d


Seriously though,not a clue,but i remember a recent discussion that says the active part of lume that makes it glow only lasts 5 to 10 years,but the radioactive elements last for aeons,
 

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I also suspect it will have much to do with the quality of the dial coating.
Interesting question
Adam
 

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I suspect it has alot to do with the non precise manufacture/substrate mix of radium and unknown nature of radiation that resulted in a significant difference of batch across all manufactures....
 

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It will depend what sort of material the dial is coated with.
A ceramic dial would probably hardly ever show signs of burns, but a painted dial could, depending what type of paint.
I have played with gamma radiation of polymers and composites a while back, some requires a very minimal dose, others are pretty much immune to radiation.
Polyester for sure didn't like radiation, polyamide wasn't too happy neither. Opposed to common belief, PTFE didn't seem to be harmed.
Carbon composites also seems less prone to damage, which would in many cases equal black paint.


Magura :)
 

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It will depend what sort of material the dial is coated with.
A ceramic dial would probably hardly ever show signs of burns, but a painted dial could, depending what type of paint.
I have played with gamma radiation of polymers and composites a while back, some requires a very minimal dose, others are pretty much immune to radiation.
Polyester for sure didn't like radiation, polyamide wasn't too happy neither. Opposed to common belief, PTFE didn't seem to be harmed.
Carbon composites also seems less prone to damage, which would in many cases equal black paint.


Magura :)
Thanks, makes sense
adam
 

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Discussion Starter · #10 ·
I love these replies! Seems nothing gets a good conversation started than talking about radium lol

The reason for the question is I am trying to establish if a dial is a redial or original. If the dial has strong radium burns I would think that would indicate a couple of things. The hands and dial still have radium which means that the finish should predate the early 1960's. The stronger the burn the older the dial?

The watch in question has not arrived yet or I would be posting pics. It is a 1945 Rolex. The dial markers and design are correct for the ref but it is marked oddly. It would have had to be a 1950's refinish to be a refinish with radium burns is my thinking. Then again maybe it was just an odd dial Rolex made. The radium markers on the dial have the same age as the hands so both would have had to be relumed with radium if the dial is a refinish.

So I was hoping that there was maybe some good guess work out there that someone looked into one time about a potential time line for a radium burn to become strong. I have that one old silver "trench" that has purple sections to the crystal...I know that would take a long time as glass is more resistant to radiation in small doses from hands than some dials.

I promise I will be posting pics once I have it in hand. :)
 

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A big variable here is that the age of radium burns isn't necessarily a function of the age of the watch, but rather of how long the watch has been stopped. So in theory, a 1930 watch that was used consistently up until recently may not have any radium burns at all, while a 1950 watch that was put in a drawer in 1952 may have significant burns.
 

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Discussion Starter · #12 ·
True but I think the dials of a watch that used radium that is in constant use would have an even age where as a stopped will be focused. Like it was said earlier, the dial material can play a big role and if the material is resistant then you would see no age or very little. If the material is one that will burn then it would be an even pattern.

In this case there are 2 distinct hand marks on the one I am getting. Below is a segment of a pic of the watch. I take risks on the watches I buy. Some work out and some don't. Worst case on this one is that it is an old redial and I may as well have it done again if it is not original. It would not be like I am destroying an original.

This is only a sneak peek.... I will start a fun thread about the entire watch soon. You can see the yellow burn though. Not the best of pics to be honest. The ones I will have later will be a crystal off pic.

 

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A big variable here is that the age of radium burns isn't necessarily a function of the age of the watch, but rather of how long the watch has been stopped. So in theory, a 1930 watch that was used consistently up until recently may not have any radium burns at all, while a 1950 watch that was put in a drawer in 1952 may have significant burns.

exact AbslomRob , this Elgin of a friend has remained for many years in a drawer

Fashion accessory Metal Watch Pocket watch Fashion accessory Clock Antique

regards enrico
 

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exact AbslomRob , this Elgin of a friend has remained for many years in a drawer

View attachment 2555970 View attachment 2555978

regards enrico
But the dial is not burnt, just the plastic crystal.
No 'water mark' round the numbers and no hand burns.

Below is similar on a 'paper' dial.
Only the plastic crystal was effected.
So that has nothing do do with sitting in a drawer with 'stationary' hands - the numerals are 'stationary' even if watch is running!



PS:
I still have this watch, it has sat in its box, in a closed drawer for 5 years - no burn/discoloration at all.
 

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Discussion Starter · #15 ·
I do see a slight haze around the numbers on the pocket watch.

Maybe if we could get a more "zoomed in" image?
 

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I do see a slight haze around the numbers on the pocket watch.
Nope - not to the extent one would expect.
The horizontal escapement of radium must be equal to vertical. Yet vertically has in both cases imprinted the crystal with the number, yet the dial and in my case paper - nothing!
 

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Discussion Starter · #17 ·
Nope - not to the extent one would expect.
The horizontal escapement of radium must be equal to vertical. Yet vertically has in both cases imprinted the crystal with the number
Agreed.

I wwould think what we are seeing is like shining a flashlight at something. It creates a spot in front but not much light to the direct sides. The other possibility is the fact that it should create a sphere of radiation around each set of numbers but being that it is on the surface of a hard material backed with metal it may act as a reflector.

One thing to also note is that both dials are black. I wonder what the extent would be on a white dial as it would be easier to see the subtle shade change at the edges.
 

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I think you also have to consider how the hands are filled with the lume. If you have skeletal (cathedral or baton) then the relationship between the lume and the dial is different if you have a solid hand with a "lume well". Think about how tough the dials often look on 1950s watches which had the lume applied to the backs of solid hands which back lit them (I forget the trade names for this...).
 

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Discussion Starter · #19 ·
I don't know the name but that sounds like an awesome look! They need to do that these days for the kids that like to put neon under their cars lol

So would a skeleton hand hold more lume then a solid hand with the top painted with the same material?
 

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I think you also have to consider how the hands are filled with the lume. If you have skeletal (cathedral or baton) then the relationship between the lume and the dial is different if you have a solid hand with a "lume well". Think about how tough the dials often look on 1950s watches which had the lume applied to the backs of solid hands which back lit them (I forget the trade names for this...).
Agreed.
 
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