Re: Can I make a radioluminescent substance at home?

yes and no...  Let me explain.

First, I would be very careful when "burning" thorium mantles.  Thorium is 
very toxic.  In some forms it is more toxic than plutonium.  You do not 
want to create oxidized thoriated contamination.  Be very, very careful not 
to breath or ingest ANY!  Realistically, I would not try this!!

As for the light production.  The zinc sulfide mixed intimately with 
thorium will produce photons, however, not in a wavelength or strength that 
is visible to the human eye.  When built into radiation detectors the 
detectors have special photomultiplier tubes that convert the photons to an 
electronic signal.

If you have the enviroment in complete darkness and you let your eyes 
adjust to the dark you may see some greenish "glow", however, it may be 
faint if at all visible.

Good luck and be careful....