WS 19 radium paint?

[Jesse Browning]

I'm restoring a Signal Corps WS Mk II CRM 43. I looked on line for information about radium paint used for the lettering. Some say radium was never used. Some say it was. Anyone actually put a detector on the various sets to find out? My radio, control boxes, variometer, and power supply all glow in the dark after exposure to bright light. The US sets I have worked on for years don't do this, even though I'm sure of the presence of radium paint on them. I had hoped to keep my vehicle radium free. Jesse.

[Chris Suslowicz]

Originally Posted by Jesse Browning

I'm restoring a Signal Corps WS Mk II CRM 43. I looked on line for information about radium paint used for the lettering. Some say radium was never used. Some say it was. Anyone actually put a detector on the various sets to find out? My radio, control boxes, variometer, and power supply all glow in the dark after exposure to bright light. The US sets I have worked on for years don't do this, even though I'm sure of the presence of radium paint on them. I had hoped to keep my vehicle radium free. Jesse.

In my experience, the only radioactive part ever used on the 19 set was the power switch on the Canadian Supply Unit No.2 (which had a luminous bead on the tip of the switch toggle). (Note: it's possible that some of the meter scales had radium paint applied, but they're behind glass and will be fairly safe.)

All the lettering that I've encountered has been standard "phosphorescent zinc sulphide" paint and contains no radioactive materials.

The "eyeball check" for the two paint types is fairly simple:

Radium paint is usually brown by this time and no longer glows - the phosphor component has been burned out by the radiation over the 60+ years since it was made. The paint is still radioactive, since radium has a very long half-life.

Non-radium paint will be green-ish in colour and will still be functional. If you shine a strong light on it (I use a Maglite) in a darkened room, it will glow after the light is removed, usually for several minutes.

You should NOT attempt to remove radium paint from anything: the dust is very dangerous if inhaled (the body treats it as calcium and tends to incorporate it into bones, where it will give you a continuous radiation exposure that can cause cancer).

Chris.

[David Dunlop]

I would have to agree with Chris, Jesse. None of the markings I have ever seen on 19-Sets over the last 40 plus years have ever showed any signs of the classic radium paint brown out effect with age. I have seen one meter with a brown face but it showed other signs indicating a likely cause for it to brown out was exposure to moisture more than anything being radioactive.

If you want to see what radium paint looks like when it ages out, its shows up very often in military pocket watches. The vast majority out there will have browned out radium paint on their dials. Not certain what causes the effect but I am suspicious UV Radiation from exposure to daylight could be a big factor. I have seen military pocket watches 70+ years old stored in their original boxes and they look like the day they were made.

David

[Jesse Browning]

Thanks for the information. I've worked on hundreds of US sets over the years, but this is the first WS 19 I've worked on.