They are not specifically sealed and will leak tiny amounts of Radon. You can remove the toggle by dismantalling the switch fron the rear. Then seal it in a small bottle or encapsulate it in epoxy resin or clear cast polyester resin (from craft shops) to improve the seal.
--- In CDV700CLUB@yahoogroups.com, "." <revtkatt@...> wrote:
> --- In CDV700CLUB@yahoogroups.com, "Phil" <n5tsx.6@> wrote:
> > I have about 20 of them.
> psycho :-P
> >It appears to be a Radium Impregnated thick paper like material under a glass dome as you suspected.
> Aha. Actually I had no idea of the structure, phosphor/radium
> coated paper would work. So, thanks for the info.
> I imagined a glass tube with dried liquid; blotter
> is easier to QA.
> Cf also trit lights, either gas
> filled /phosphor lined like fluorescent tubes
> or plated with phosphor + trit chems directly, no gas.
> (Only recently learned about the latter, seems safer?
> Or at least easier to make.)
> My eyes are getting old, so I thought I'd ask this list,
> rather than try to non-destructively reverse
> engineer the dot by looking at it through the dome, which
> didn't reveal much when I tried :-)