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Tumble burnishing flat copper disks


#1
  1. i have just rotary tumbled some flat copper disks in steel shot.
    as judy hoch described, the edges of the flat disk rolled up a bit.
    can i remove the rolled edge if i burnish in a ceramic medium instead
    of steel shot? do i remember that the ceramic medium will not work
    harden the pieces? i wanted the steel shot to work harden the
    pieces. if i ran the pieces first in steel shot and then in a
    ceramic or an abrasive medium, would that trim off the little ridge?
    (when i burnished off the raised metal, it seemed to scrape off
    instead of being pushed down.)

in her book, judy says that dulling the sharp edges before tumbling
with shot will avoid the rolled up edges. does the edge need to be
beveled, or will just a slight rounding do it? i’m imaging using the
burnisher again. unfortunately, when i burnished my pieces after
tumbling my burnisher slipped a couple of times, so i had to go back
an clean that up. i’d like to avoid the burnishing if i can.

  1. i have used separate shot and solution for the copper. i think
    i remember that i shouldn’t combine metals, but i can’t find where i
    read that. is it ok to combine silver and copper in a steel shot
    tumble?

thanks again,
jean adkins


#2
          1.  i have just rotary tumbled some flat copper disks in
steel shot. as judy hoch described, the edges of the flat disk
rolled up a bit. can i remove the rolled edge if i burnish in a
ceramic medium instead of steel shot?  do i remember that the
ceramic medium will not work harden the pieces?  i wanted the
steel shot to work harden the pieces.  if i ran the pieces first in
steel shot and then in a ceramic or an abrasive medium, would that
trim off the little ridge? (when i burnished off the raised metal,
it seemed to scrape off instead of being pushed down.) in her book,
judy says that dulling the sharp edges before tumbling with shot
will avoid the rolled up edges.  does the edge need to be beveled,
or will just a slight rounding do it?  i'm imaging using the
burnisher again.  unfortunately, when i burnished my pieces after
tumbling my burnisher slipped a couple of times, so i had to go
back an clean that up.  i'd like to avoid the burnishing if i can. 

Ok - I’d guess that the reason for the rolled edge is that your disks
were cut out with a dull die. Thus the edge tears rather than being
cut. I’d suggest that you sand the edge with a sanding disk on your
flex shaft, or use a file, or use an expanding drum with 400 grit to
knock off the torn edges. alternately, you could run the disks first
in an abrasive tumbling media to round the edge, the run in the steel
to harden and burnish.

     2.  i have used separate shot and solution for the copper.  i
think i remember that i shouldn't combine metals, but i can't find
where i read that.  is it ok to combine silver and copper in a
steel shot tumble? 

The caution on mixing metals is that sometimes one colors the other.
Try it, it will probably work ok.

Judy Hoch, G.G.
@Judy_Hoch