NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Radium illumination
From: George Huxtable
Date: 2010 Sep 6, 08:45 +0100
From: George Huxtable
Date: 2010 Sep 6, 08:45 +0100
Gary wrote- | Or maybe one can just buy new radium paint. This auction just ended. | | http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350376559549 ================ No, Gary. That won't be Radium paint, and wasn't advertised as such; just as non-toxic luminous paint, which is the sort of stuff described by Bill Morris, that needs activating first by shining a light on it. I doubt if Radium paint is available anywhere, in any form, anymore. The only truly luminous self-illumination that I know of, available at present, is powered by the low-energy beta-particles emitted by the radioactive gas Tritium (an isotope of Hydrogen, and a fuel component of the Hydrogen bomb). This has been used in emergency-illumination of warning signs in aircraft and elsewhere, and maybe still is. Usually the Tritium is contained in a sealed glass capsule, with luminous material painted on the inside. I have nice hand bearing-compasses, initially from France, labelled Opti-compass or Minicompas, of hockey-puck form, that were lit this way. Similar compasses, with what looks like the same type of illumination, are still available under the French label Vion. Unfortunately, Tritium has a half-life of about 15 years, so the light inevitably fades. Whether the luminous material loses its magic property as well, I don't know, but the illumination of these old compasses, combined with my dimming old eyes, is no longer useful to me, and I've replaced one with a light-emitting diode (LED) and battery (and a resistor to limit the current) , which works well. The snag is that I haven't (yet) been able to find a non-magnetic 3-volt battery, so the end-result has to be bigger assembly just to get the battery away to a safe distance. If anyone has a solution to that , it would be welcomed. George. contact George Huxtable, at george@hux.me.uk or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.