I agree with Brian! Pure tin, or 96/4 tin/sil, 96/4 tin/cu are
non-toxic and have many uses in jewelery…but more in the fashion
jewellery and specially in the repairs to fashion jewellery. How
else can we solder a post onto an enamelled silver motif, or onto a
gold plated rhinestone cluster ear-ring? (OK this was before the
pulse-arc or lazer but the method remains valid). To replace a broken
pewter eye with a silver eye onto a cast pewter item is easy to do
with tin solder. I never add lead. If the original item contains lead
then it’s not my doing as I will only add tin, or re-melt the
existing lead.
The difference between a plumber and a jeweller is the plumber is
accustomed to monster items and soldering irons, and the jeweller
will use a miniture iron with barely enough solder to fill the joint.
Electronics technicians/artists will know this. Sweat soldering with
tin is easy and predictable with practise.
If the item is stamped with a hallmark then be sure to tell the
customer that adding tin will devalue the item. Most often the
customer will value practical usage above the inherent value of the 1
or 2 grams of silver or gold that the hallmark refers to.
Alastair