Pre-polishing procedure

For finishing chain I have recently begun to use silica impregnated
pyramids (from Gesswein) in three grits prior to polishing with
stainless shot in my tumbler. Do you have any idea how long these
impregnated pyramids last before replacing? After about three times
using the same pyramids, I sometimes see a greenish cast to the
solution and wonder if it just begins to break down. I usually leave
each grit running for about a half hour each before changing to
stainless shot polishing tumble. Results are excellent but i haven’t
solved length of time or replacing pyramids.

Ruth Mary

For finishing chain I have recently begun to use silica
impregnated pyramids (from Gesswein) in three grits prior to
polishing with stainless shot in my tumbler. Do you have any idea
how long these impregnated pyramids last before replacing? After
about three times using the same pyramids, I sometimes see a
greenish cast to the solution and wonder if it just begins to break
down. I usually leave each grit running for about a half hour each
before changing to stainless shot polishing tumble. Results are
excellent but I haven't solved length of time or replacing
pyramids. 

Ruth - it’s great to see that you are using some abrasive media
prior to burnishing your chain. It’s a step that is essential and too
often skipped.

To answer your question - the color you are seeing is from the color
of the carrier of the silica. Or said in another way, the silica is
embedded in the green stuff and as the green wears away, it exposes
more abrasive. Yes, absolutely, the media will wear down, but since
the abrasive is embedded in the whole pyramid, the time to replace it
is when it gets too small. It will work until it disappears. However,
the weight of the media influences how fast it works so as it wears
away, you will find that it takes longer to get the same result as
when new.

Hopefully, you are running the abrasive in a vibratory tumbler. It
is much faster than using a rotary - about 4 to 5 times faster.
However, I think you are working too hard. If you are fabricating
your chain, you only need a fine grit cycle. It does need to be at
least 3 to 4 hours to actually work in a vibratory tumbler. In a
rotary one, run for 12 hours or longer. Then in a clean rotary
tumbler, run with shot for 30 minutes. Depending on the detail in
your chain, you may want to finish to a fine high polish in dry
media. There are so many variations to this process that you might
want to get the little book I wrote on the subject.

Judy Hoch
Marstal Smithy