Getting the metal hot enough to weld will burn away any residual lead. If you're really paranoid, wear some sort of charcoal filtered respirator to avoid breathing any vaporized lead fumes that might be be created by the welding procedure.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!