Hi All, Somewhat related to my previous post about rolling mills, I
am going to purchase one primarily to be able to create some stock a
little heavier than the 10ga I can easily get. In the past my
attempts to recycle scrap sterling met with disaster-crumbly pitted
ingots the norm. I was using “clean scrap” ie no solder but it had
been heated. I don’t recall how I cleaned it but I was using a high
quality flux in the melting of it. I mastered getting a nice pour
with no folds but even annealling after every pass through the mill
gave me the same resluts.
This time I’m determined to get it right even if I have to use
casting grain. I’m not interested in recycling as much as the
finished product. Would fresh casting grain be a solution? Any secret
fluxes or crucibles? ingot molds? I was using the 2 piece molds
getting 3"x5/8" ingots but tried th longer oepn molds with worse
results.
Warren: Sounds like you have a metal contamination or some other
alloy problem. The only thing I can think of that will make the
metal crumble. I suggest you start with a new batch of silver and
use a rolling alloy until you get the hang of it and then try mixing
your used scrap 50/ 50 with fresh metal… Give a call to one of the
refining houses and tell them what you need in an alloy and see what
they recommend. I personally use United Precious Metals S88 master
alloy for sterling, which is a low ox alloy. I use it for casting as
well as milling and have had no problems. I have however found that
it does work harden a little faster that milling stock and has to be
annealed more frequently when hammer forging. Frank Goss
When preparing large stock I was taught to forge the resulting
ingot. Get it red hot and belt it with a hammer in all directions -
like working iron. I seldom get any porosity problems.