The question - In tumbling silver jewelry, what are the different
used for and what should be the ratios vs metal?
Robert - lets start with general shapes - in plastic or ceramic
Think about what kind of detail you have on your pieces. If you have
lots of tiny spaces, or lots of detail, you would probably use
something with points such as pyramids. If your work is smooth, the
cones would work better.
If you have lots of tiny holes, like a ring with multiple baskets,
probably pre-process the ring with a magentic finisher - the little
steel pins do a good job of getting inside the heads.
All abrasive media has the grit distributed throughout the shapes,
so as the media wears, more abrasive is exposed. The weight of the
media matters - ceramic media with aluminum oxides abrasive is
usually coarse and suitable for prefinish on castings. This heavy
coarse media is suitable for steel as well. The ceramic abrasives are
very aggressive and will remove lots of metal so they are not used
for work with fine detail. The plastic media comes in many shapes and
colors - so using the guidelines about shape, select coarse, medium
or fine abrasives.
This ceramic or plastic media is used in a vibratory tumbler and is
run wet to encourage media movement and to remove the worn bits via
a flow thru system.
As to proportion of metal to media - you are using the media for
finishing but also to cushion your work from impingement. By volume
I wouldn’t exceed 25% metal and get better results with 15%.
My work has a subtle texture from Japanese paper used with a rolling
mill (I use Durston mills, both manual and powered). It is mostly
fabricated. I run 4 to 6 hours in Clean Cut Plastic Cone Media, Fine
Cut with a purpose made liquid of sunsheen Deburring compound
diluted per instructions on bottle. I use a Raytech TV25SS vibratory
tumbler with flow thru liquid. My media is rated to provide a 3
micron finish but to really achieve that result, it requires some
extra early processes.
There is an enormous stash of on mass finishing on the
web, in addition to books specific to the issue.
This discussion is trying to answer your specific question - but
omits all the final finishing bits of burnishing in various tumblers.
Email me directly if you wish for more detail. I’ve spent 20 plus
years trying to figure out the optimum process for my jewelry so
maybe I could help. In all of these questions, it really helps to
have a picture of what you are finishing, both for shape and