Neil - My experience with the Otec mini was gathered when I did
research in 2002 for the fourth edition of Tumble Finishing for
There is a real size limitation on the pieces you can process. I
found that a maximum dimension is about 1 1/4 inches. The machine
works best on medium weight cast pieces. Fabricated work, especially
with ear wires in silver, was damaged and unusable in the abrasive
bowl. To get the rapid abrasive cleaning, the machine is very
dynamic, and IMHO very hard on lighter weight work. The best use of
the machine is in the dry mode, with the ring holder because it
removes the impact of one piece on another.
My alternative to the Otec machine is to use a magnetic pin finisher
to start the polishing process for detailed pieces, then the
vibratory tumbler for classic deburring, then either a rotary drum
with stainless steel, or a vibratory tumbler with wood chips and
wood pegs charged with simichrome or iron oxide (red stuff) for gold
or chromium oxide (green stuff) for silver. It takes longer, but
your work survives and the result is predictably very good.
Judy Hoch, G.G.