Tire <-> rim sealant?

[JAMES_S_WALLACE@HP-Canada-om1.om.hp.com]

     Greetings,
     
     I recently had a couple of my rims glass-bead-blasted, and they came 
     out beautifully. I primed them and painted them with Ford Silver 
     (Argent d'Henri), and they look just fine.
     I put the tires on the rims, inflated them, and they both leaked all 
     around the perimeter where the tire meets the rim. Then I remembered 
     that at tire shops they always slop some kind of soapy liquid on there 
     before inflating.
     Does anyone know what can be used for this purpose that one may have 
     lying around the house?
     
     Thanks,
     Jim Wallace
     '60 TR3