A friend of mine asked me to convert 50 oz of deox sterling silver
castings into plate. I worked this just like I normally do for
sterling. Melt the castings and pour the ingot, pickle, and dry.
Then I hammer the ingot lightly on both sides with a ball peen
hammer and anneal. Then I begin the rolling and anneal as necessary.
The problem is that after two or three passes through the mill I
notice spots in the ingot that are cracking. It is like they were
in the ingot from the beginning, not like cracking on the edges from
too much rolling before annealing. Any thoughts? Has anyone had
experience with this? Thanks.
in my experience with Deox silver, you cannot treat it as regular
sterling. First (and I use the master 88 alloy from United precious
metals) it starts out more malleable and tends to work harden more
quickly. That being said my standard procedure for ingots is to file
the surface until all the small pits are removed. The silver seems
to roll over the pits but not to fill them, it creates cavities that
then create cracks in the ingot. I usually file the billet smooth
and then make a couple of passes through the mill. I then anneal and
check for bubbles where hollows might have formed.Any hollows formed
can usually be removed with a quick hot torch melting the offending
spot. I then roll pretty much as usual making sure to reverse the
ingot and flip it over with each pass though the mill. I anneal
about 30% more than I would with regular alloy.One last thing be sure
you are using a good sterling flux I find boric acid is not heavy
enough for melting but seems to work fine for soldering.