Casting and Impurities

Jewelry Discussion
1

Hi to all those casters and metals experts out there. I was wondering
if there was an acceptable amount of oxygen allowable in casting
grain. We have recently had ours tested, but have no idea what our
numbers mean. How many parts per million are just fine, and at what
level should I be concerned? An what about iron? Is there an
acceptable level of iron?

Troy Hines

2 
    Hi to all those casters and metals experts out there. I was 
wondering if there was an acceptable amount of oxygen allowable in
casting grain. We have recently had ours tested, but have no idea
what our numbers mean. How many parts per million are just fine,
and at  what level should I be concerned? An what about iron? Is
there an acceptable level of iron?

I know that you want to keep it in the 15-20 ppm range but I did not
know what the max should be so I spoke with a metallurgist at one
of the main metals suppliers His response was if you can keep it
below 20 ppm that is great at above 30 ppm you can start having
problems from too much oxygen. At levels of 35 ppm you will start
to see bad problems if you furnace solder. He recommended some
corrective action be taken if it was above 30 ppm. I forgot to ask
about the iron, I will the next time we talk.

Jim