Hi Mary,

Silver bars should work just fine but make sure they are high quality silver. 
They need to be at least .999 pure silver if you are planing on drinking the 
stuff that you make. Sterling silver is not considered a good enough grade 
because it contains trace metals that may be harmful. Hope this helps.

Best wishes,
Andy (^_^)

From: Mary Lou Borgert 

Andy can one use silver bars?

mary