[R-390] meter luminescence

Chris kc9ieq at yahoo.com
Wed Jan 15 23:15:57 EST 2014 

I was told by a rather well known physicist/ham that adding a new phosphorous coating on top of the old "burned" out paint would NOT work-  That the radium must be much more closely bonded to the reactive particles for it to glow.  

Has anybody actually successfully revitalized the stuff using this method?  

Chris 

Sent from my outdated iPhone wireless thingy

On Jan 15, 2014, at 7:43 PM, "Duffy Floyd" <duffyf56 at verizon.net> wrote:

> The Radioluminescent paint in this era used Radium as the "active" agent.
> Radium is an Alpha emitter when it decays. While it is possible some of the
> daughter products give off a VERY slight amount of gamma or beta particles
> as they decay, the VAST majority of all radiation from these meters is alpha
> radiation. Alpha radiation is able to shielded by single layer of dead skin
> so unless the meter face glass is broken there is NO chance of alpha
> contamination.  Any concern about alpha radiation relates to if it is
> ingested. Moral of the story.....don't eat the needles or meter faces. 
> 
> 
> 
> From everyone's favorite source of info....Wikipedia :-)
> 
> In the second half of the 20th century, radium was progressively replaced
> with promethium-147. Promethium is only a relatively low-energy
> beta-emitter, which, unlike alpha emitters, does not degrade the phosphor
> lattice and the luminosity of the material does not degrade so fast.
> Promethium-based paints are significantly safer than radium; the Pm-147
> half-life is however only 2.62 years, it is therefore not too suitable for
> long-life applications.
> 
> Promethium-based paint was used to illuminate Apollo Lunar Module electrical
> switch tips and painted on control panels of the Lunar Roving Vehicle.
> 
> "Radioluminescent paint was invented in 1908 and originally incorporated
> radium-226. The toxicity of radium was not initially understood, and
> radium-based paint saw widespread use in, for example, watches and aircraft
> instruments. During the 1920s and 1930s, the harmful effects of this paint
> became increasingly clear. A notorious case involved the "Radium Girls", a
> group of women who painted watchfaces and later suffered adverse health
> effects from ingestion. It is now recognized that radium paint requires
> great care in application, maintenance and disposal to avoid creation of a
> hazardous condition.
> 
> Radium dials were almost always painted by young women, who used to 'point'
> their brushes by licking and shaping the bristles prior to painting the fine
> lines and numbers on the dials. This practice resulted in the ingestion of
> radium, which caused serious jaw-bone degeneration and malignancy and other
> dental diseases reminiscent of phossy jaw. The disease, radium-induced
> osteonecrosis, was recognized as an occupational disease in 1925 after a
> group of radium painters, known as the Radium Girls, from the United States
> Radium Corporation sued. By 1930, all dial painters stopped pointing their
> brushes by mouth. Stopping this practice drastically reduced the amount of
> radium ingested and therefore, the incidence of malignancy, to zero by 1950
> among the workers who were studied.
> 
> Radium paint used silver-doped zinc sulfide phosphor, usually doped with
> copper (for green light), silver (blue-green), and more rarely
> copper-magnesium (for yellow-orange light). The phosphor degrades relatively
> fast and the dials lose luminosity in several years to a few decades,
> despite the long half-life of the Ra-226 isotope (1600 years); clocks and
> other devices available from antique shops and other sources therefore are
> not luminous anymore, though they are still radioactive and can be
> identified with a Geiger counter. The dials can be renovated by application
> of a very thin layer of fresh phosphor, without the radium content (with the
> original material still acting as the energy source); the phosphor layer has
> to be thin due to the light self-absorption in the material."
> 
> Duffy Floyd
> N3JHA
> 
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Jim Barrie
> Sent: Wednesday, January 15, 2014 3:15 PM
> To: Ted Breaux; rbethman; r-390 at mailman.qth.net
> Subject: Re: [R-390] meter luminescence
> 
> I was at Fair Radio and stuck Geiger counter up to the meter face of an
> R-390A and it definitely read up scale. Other that it was a yellow CD
> counter, have no idea what it was accurately reading.
> I bought that one. So far I have not. Glowed in the dark, lost any body hair
> or had any body parts fall off. L O L.
> Jim
> WA8SDF
> From: Ted Breaux
> Sent: 1/15/2014 2:56 PM
> To: rbethman; r-390 at mailman.qth.net
> Subject: Re: [R-390] meter luminescence
> The Plutonium comment was meant as a Joke.
> 
> 
> ----- Original Message -----
> From: "rbethman" <rbethman at comcast.net>
> To: <r-390 at mailman.qth.net>
> Sent: Wednesday, January 15, 2014 11:18 AM
> Subject: Re: [R-390] meter luminescence
> 
> 
>> The idea of Plutonium on dial faces is absolutely absurd!
>> 
>> It takes a Uranium fissile process to create Plutonium - period.
>> 
>> The radioactive material - Plutonium - is HIGHLY radioactive and WILL 
>> remain so for some 24 ** (4) or longer.  IOW - 24000 years for the 
>> half-life.
>> 
>> The military has NEVER used such.  The only radioactive elements used, 
>> have been Radium, and Tritium.
>> 
>> Bob - N0DGN
>> 
>> 
>> On 1/15/2014 11:20 AM, Ted Breaux wrote:
>>> Plutonium is known to do that!
>>> 
>>> 
>>> ----- Original Message ----- From: "KA9EGW" <ka9egw1 at britewerkz.com>
>>> To: <r-390 at mailman.qth.net>
>>> Sent: Wednesday, January 15, 2014 8:14 AM
>>> Subject: [R-390] meter luminescence
>>> 
>>> 
>>>> Seen plenty of blah brown meters that do nothing but move the 
>>>> pointer, in '390's and '390A's, in my day.  Never before seen ones 
>>>> where the markings glow a "Luna Moth green" after exposure to light, 
>>>> like the hands on a Big Ben clock of some years back.  Were there 
>>>> actually meters that had the strontium aluminum silicate [I'm 
>>>> guessing at the composition here] rather than the radium?  73, Brian 
>>>> KA9EGW
>> 
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