My experience with years of work with both the S88 and S57NA alloy
sterlings have shown them to work easier than traditional
sterling, with far less fire scale issues, take deep dark oxidation
when required, and are quite easy to draw or roll. I don't
recommend copper alloyed sterling to my students anymore because of
the many problems inherent in the metal.
There are no inherent problems in traditional sterling alloy. There
is at least one problem that I discovered with alloys that boast
their resistance to oxidation.
A lot of my work requires soldering two parts, which are touching in
several contact points. As an example, take a look at my video
"Coronet Cluster" The diamond holding gallery attaches to under-bezel
via multiple soldered joints ( one per each diamond ). Two pieces
bound by wire and soldered in one shot, moving flame from one joint
to the next. When I released the DVD, I was getting a lot of emails
that there were problems with soldering. Joints were coming apart
during polishing. In each and every case they were using Argentium
I got some of it and gave it a go. What happening is that when alloy
is heated, it forms film of Germanium oxide on the surface. The first
joint will solder fine, and may be the second one, but subsequent
joints, while solder flows, there are no real adhesion takes place.
Joint behaves like cold soldered. To remedy this, I had to after
every two joints to pickle, neutralize, wash, and dry. I also
realize that standard pickle is not effective in removing germanium
oxide. One has to boil things lye to get rid of it. So it is Royal
Pain in you know where, to work with it.
So these new technological wonders may be great alloys for casting,
granulation, and the like, but for real fabrication they are
I strongly recommend, until manufactures develop specialized fluxes
to deal with germanium oxide layer, to stay away from it.