Buff-stick all flat surfaces using #280 grit abrasive paper, then #320 grit
paper. Again, stroke in alternating diagonal directions and overlap the
strokes.
Using a unitized wheel, reduce the surface scratches left by the abrasive
papers. Start with a #400- then a #500-, and finish with a #600-grit wheel.
Remember
to use overlapping and alternating diagonal strokes.
Polish the inside of rings with white cutting compound or leave a satin finish.
One note of caution about this step: A rough surface or hollow section within a
ring will
promote the capture of household chemicals, dirt, moisture, body oils, and acids
that may lead to skin irritation. This skin irritation, known as dermatitis, may
lead the
wearer to believe they are allergic to the precious metal used in the ring.
It is important when polishing to keep the polishing buffs, brushes, wheels and
laps clean and freshly charged with the cutting/finishing compounds. These
compounds are more abrasive when fresh, allowing for quicker cutting and
polishing.
The outside surfaces should be buffed with white cutting compounds. Buff the
outside surface with the white cutting compound in a diagonal direction, then
reverse the direction of the buffing to cross over the original direction.
Flat-lap all flat surfaces using a white cutting compound. Clean the surface and
repeat the lapping with an orange polishing compound (aluminum oxide). Again,
clean the surface when the operation is complete.
Using a muslin buff charged with orange polishing compound, lightly buff the
outside surfaces. This should give a very high luster and a reflective surface.
If platinum is being joined to karat gold, it is important to finish the
platinum segment completely prior to assembly because karat gold polishes faster
than platinum. Failure to finish or polish the platinum prior to joining it to
karat gold will result in over-polishing the karat gold component.
Platinum will not oxidize during the brazing/welding process, so the finish will
not be altered by brazing or welding. However, the use of an anti-oxidizing
glaze, such a boric acid and alcohol solution, should be used to protect the
polished surface of the gold from oxidation.
In the event that you are re-polishing an already polished jewelry item, care
should be taken not to finish or polish out the manufacturers hallmark. This
hallmark is the guarantee that the product is platinum. If it is removed, it
should be replaced before the product is released to the end user.