November 1, 2018 at 4:16 pm #10530Bruce MorgensternCVRS Member
This article came from the Yahoo Group “The Tube Collectors Association” “TCA”.
Has anyone ever tried to apply a new coat of zinc sulfide over the old coating to renew the dials? Jim
Radium paint was used to make lettering glow in the dark. A small amount of a radioactive substance was mixed with fluorescent (phosphorscent?) material to energize it without an
external source. When the radioactive material decays sufficiently the glow becomes very dim or disappears. The radioactive material can still be dangerous. This sort of paint was widely used on clock and watch dials and aircraft instruments for a couple of decades.
It has a half life of 1600 years, meaning ww2 dials and panels are virtually as hot as when they were made. It is the zinc sulfide phosphor that degrades , usually with trace metals doped with an activator, such as copper (for green light), silver (blue-green), and more rarely copper-magnesium (for yellow-orange light).
The Radium Girls were female factory workers who contracted radiation poisoning from painting watch dials with self-luminous paint. Painting was done by women at three different sites in the United States, and the term now applies to the women working at the facilities: the first, a United States Radium factory in Orange, New Jersey, beginning around 1917; the facility at Ottawa, Illinois, beginning in the early 1920s; and a third facility in Waterbury, Connecticut.
The women in each facility had been told the paint was harmless, and subsequently ingested deadly amounts of radium after being instructed to “point” their brushes on their lips in order to give them a fine point; some also painted their fingernails, face and teeth with the glowing substance. The women were instructed to point their brushes because using rags, or a water rinse, caused them to waste too much time and waste too much of the material made from powdered radium, gum arabic and water.
Five of the women in New Jersey challenged their employer in a case over the right of individual workers who contract occupational diseases to sue their employers under New Jersey’s occupational injuries law, which at the time had a two-year statute of limitations, but settled out of court in 1928. Five women in Illinois who were employees of the Radium Dial Company (which was unaffiliated with the United States Radium Corporation) sued their employer under Illinois law, winning damages in 1938November 5, 2018 at 1:02 pm #10543philForum Participant
it brings up a good question ,at what date did the glow in the dark letters become less radioactive? they still make glow in the dark stuff today, but I believe they fixed the issue at some point by using less radioactive materials and we may not need to fear stuff that was past a certain date,,, or should we? I wonder what would happen if you took a Geiger counter into a modern dollar store?November 8, 2018 at 5:51 pm #10567John BartleyForum Participant
Just as an aside to the discussion on radium painting dials … One of the long time business families in Ottawa was the Ashtons, who (among other interests) owned a company that serviced equipment such as printing presses etc. from a building in Stittsville (just west of Ottawa). The following is as told to me by Carl Ashton many, many years ago, so please excuse if some of the details are incorrect. The basics should be close enough for playing grenades. During WW2 their plant in Stittsville was used by Bristol Aviation to manufacture parts of the instruments/communications gear used in their airplanes. Carl told me that they employed local women to paint the radium solution onto the dials and indicator needles at this factory. He described how they would form their brushes into a fine point by licking the brush hairs with their tongues, then dip them into the radium paint. They would then rinse off the brushes and repeat. He also told me that the radium was mined and refined locally. This meant little to me until I met Bill Argue, a local farmer and pilot whose father’s farm was expropriated (bought) during WW2 and used as the land to build the Carp Airport. The Carp Airport was a BCATP bombing or bomb aiming school I think. He told me that the radium ore came from a small quarry at the intersection of the Richardson Side Road (now Kanata Ave.) and The Goulbourn Forced Road. Yes, as a youngster I swam in that quarry many times as it was only a couple of miles from the farm I grew up on…. The Ottawa area is known for high levels of Radon in the ground, so given that I have heard this story now from two, level headed, reputable sources, I have to assume it is true. In the images attached, the quarry (now filled in) is at the north corner of Kanata Ave and Goulbourn Forced Road. The Ashton factory was located where is now shown as Stittsville Trailer.
ps : sorry for the off topic diversion.
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