Oven Soldering For Sterling

Hi everyone,

Does anyone know of any good resources on jewelry oven soldering?
Books? Internet links? I am trouble-shooting a problem and in my
research I have found very little useful

We keep our oven set at a constant temperature of 1500 deg F and
regulate the solder flow by adjusting the belt speed. I am beginning
to think that 1500 is way too hot for some applications, even with a
faster belt speed, but do not want to reset the entire system
without a bit of research. If my hunch is a failure, my colleagues
will point and laugh, and it could be very expensive. Any tips from
the marvelous brains out there?

Also, why would some of our sterling castings come out of the
furnace with a pinkish color all over, and sometimes come out just
fine? What is happening inside to bring so much copper to the
surface? Is there some kind of possible contamination from our
solder? Rotten batch of metal? Chemical reaction in the furnace
atmosphere? Elves? Magic?