In the years that I have been at the bench one of the best pieces of
advice I have been able to give other jewelers is how to remove those
pesky broken drill bits. It works on all non-ferrous metals but
because it involves boiling requires special attention and care.
Take the item and place it in a glass beaker, fill it with enough
water to allow it to safely boil for about 30 minutes. Mix in about
3 tablespoons per 400 ML of Alum (enough to make a supersaturated
solution). As the mixture heats, just before it boils you will
observe tiny bubbles coming from the hole in which the drill (or any
other steel part) is located. Check the water level every 5 minutes
to ensure there is enough water and that it isn’t boiling over. When
small bubbles can no longer be seen coming out of the hole then the
drill is out and the item can be removed from the beaker.
keep these points in mind
the more area that can be reached by the liquid the better. If
you can drill or bur from the back side to allow the action to work
from both ends, better!
never leave the water boiling unattended!
In the past I have used this method with diamonds rubies and
sapphires, BUT, I don’t trust as many stones now, there are just too
many treatments out there that i have suspicion about. It is best to
remove stones, just to be on the safe side.
Alum can be purchased at most drug stores. You may have to have
it ordered from the large chains, it is best to try and find an
independent pharmacy. It is commonly used to stop bleeding from
minor shaving cuts.
You don’t need a rolling boil, as long as it is simmering and you
can see the small bubbles, your getting proper action.
This will take 20 to 45 minutes depending on the size of the drill
and how much access there is to the drill.
Thanks to my former jewelry instructor Grey Lawrence, watchmaker and
jeweler, Okmulgee OK for this little bit of some 20 years
JA Certified Master Bench Jeweler