Version 1.05 March 2020
27
6.2.7 PRE-POLISH
The pre-polish lap is used (for example, a BATT Lap), with a 3000 diamond compound. You repeat the
sequence of the prior steps. Examine the facet surfaces
– it should be starting to look good..
L
et’s move directly to the final polish step.
6.2.8 POLISHING THE PAVILION
The technique of polishing that is recommended here is the use of Ultra Laps (these laps have the polishing
medium deposited on a mylar film). This is one particular method
—it is fast, allows the use of the abundant
water for lubrication, and does not demand too much by way of developing skills (you will use many additional
polishing methods as time goes by). Ultra Laps do cause a very slight rounding of the edge of the facet--but
when (and if) you get to worrying about that, you will have become a good faceter and know a lot about various
polishing methods.
In polishing this first stone, use an Aluminum Oxide Ultra Lap. Flood the surface of the polish lap with water
and place the Ultra Lap onto it.. Then tighten the Safety Nut. Press out the air bubbles you see through the
mylar--wet the surface of the Ultra Lap and push the bubble out with your fingers. The water on the surface of
the supporting lap will be adequate to hold the mylar down while it is used for polishing--adhesive is not needed.
Set down the stone onto the Ultra Lap surface
—you’ll need to do a little raising of the vertical position to
compensate for the Ultra Lap
—resetting the target 40.00. Having done that—the facet on the lap—the angle
setting at 40.00--back off the fine adjustment screw about a half turn. The 40.00 reading is maintained by the
stone on the lap surface. Turn on the motor and set a slow speed--2 or 3 on the speed control dial. Polish in
the same way you had been previously grinding, -- you can bear down to speed the polishing (you may see
some fluctuation of the set 40.00
—reading some lap error—that’s OK)..
Lift the stone to inspect the surface-- you need to position the lap so the light glances off the surface and allows
you to see the grinding scratches. You will see the polished surface as it gradually develops.
Don’t settle for
less than an excellent polish
—NO scratches. If the facet is being stubborn about polishing, you can try
reversing the direction of the lap
—that often helps.
Having completed the polishing on one facet, continue with the others, and having completed the main facets
go on to the break facets. Note that you are polishing in reverse order to the grinding sequence.
As you use the Ultra Lap you will wear away the polishing medium, or it may seem to slice off in places. You
can continue to use the Ultra lap as long as there is some area in which to polish--running the stone over a bare
or bumpy spot does no damage. The individual Ultra lap should take you through at least several stones.
When you finish polishing the last break facet, you have finished the pavilion. Make a last inspection to satisfy
yourself with the quality of the polish.
You are ready to Transfer the stone--cementing the pavilion onto a new dop, so that the Crown can be
completed. Remove the dop/stone from the spindle.
