A lead tin alloy will get softer over time. How long i dont know. Alloys with antimony dont do this. Antimony, if water dropped, full hardness is reached later depending on the % of antimony. 2% about 2 weeks. 6% full hardness in 1 hour. http://www.keytometals.com/page.aspx...site=ktn&NM=88 Correction- Lead tin alloys-
. Lead-tin alloys, for example, may recrystailize immediately and completely at room temperature
I guess this means the alloy retains the same BHN ? But i seem to remember reading it gets softer with time, some where??