How to Create Black Coral Beads

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How to Create Black Coral Beads
By Donald C. Dietz
(See Lapidary Journal, December 2000)

You have learned how to collect, preserve, and polish black coral and
how to use it to create beautiful and unique items of jewelry. But as
you look at your dwindling pile of coral rough, there remain short
lengths of limbs and trunk, or chunks that have too many brown spots
(decay) for use in your jewelry designs. But you hate to throw away
this material which is difficult to come by to say the least. What to
do?

Well, there is a way to use all but the smallest pieces by creating
lovely BLACK CORAL BEADS of many different sizes and shapes with
little effort or investment.

MATERIALS NEEDED:

Black Coral, an alcohol lamp, a sharp pointed awl, a 1.5 mm twist
drill, a flex-shaft such as Foredom or Dremel (but any small drill
motor or even a hand drill will do), a piece of steel rod
approximately 1.6 to 1.8 mm in diameter about 4 inches long, a 5 inch
length of dowel, a ¼ to ½ HP motor with a pointed spindle, several 4
to 6 inch discs made of 1/8 inch plywood or heavy cardboard, several
sheets of garnet or silicon carbide paper from 100 to 400 grit, a 4 to
6 inch sewn muslin polishing wheel, polish (ZAM, Fabuluster, or black
emery), and a small medium cut file. Several medium size high-speed
steel burrs in ball, cone or bud shapes could be useful as well.

Any size or shape of Black Coral can be used but initially, try to use
straight pieces about 10 to 15 mm long and nicely rounded 4 to 8 mm in
diameter. It can be rough, smoothed or polished. Pure black pieces
are great if you have them, but don’t discount the brown ones or those
with brown spots; they make beautiful patterns in finished beads.
Stay away from crotches, areas where there are obvious holes into the
interior or pieces in which the layers of coral are separated or
filled with calcaceous material.

Before beginning to cut your beads, there are two items that need to
be prepared.



On pieces of 1/8 inch plywood or heavy cardboard draw square boxes 6
inches square. Draw lines from corner to corner--the X indicates exact
center. With the awl punch a small hole in the center of each disc.
Stiffen the holes and the area around them with shellac, nail polish,
or epoxy glue. When this is dry, cut a round disc from each square
using a heavy-duty hobby-knife. Also, cut discs from several
different grits of sandpaper but be sure to have at least a 150 grit
and a 400 grit. NOTE: Five or six inch discs are recommended because
you can find ready cut sandpaper or fabric discs of these sizes at
your hardware store. Glue the sandpaper to the plywood or cardboard
discs. If you are using cardboard, any glue will do, as you will
throw them away when they are worn out. If you use plywood,
feathering adhesive will permit it’s reuse several times before it
must be replaced. You may want to put a different grit paper on each
side of a disc to save time. When finished, write the grit on the
surface of the disc with a laundry marker.
The second tool will be used to help hold the beads while sanding and
polishing. Use a 5 to 6 inch smooth wooden dowel about ¼ to ½ inch in
diameter. The diameter will depend on the size of your hand and how
easy is it for you to twirl it around at least one full rotation
without stopping. This action is important to create a nice round
bead with no flat spots. Locate the center of the dowel and with the
awl make a mark. Drill a hole 2mm by about ½ inch deep. Cut a 2-inch
piece from the steel rod and imbed it with epoxy into the hole in the
dowel. As it dries, adjust the rod so it sticks straight out of the
dowel. If it is off center even slightly, it could affect the shape
of the bead. Let it dry overnight, then with a small grinder, grind
the tip of the rod about ½ inch down from the end to a diameter of
approximately 1.6mm. You may want to adjust this later so, rather
than too thin, leave it a little fatter to begin with

For the first bead, choose a piece of coral 12 to 14 mm long and about
6 mm in diameter. If it is not quite straight, gently heat it over the
alcohol lamp and bend it straight. One way is to make a wooden block
with several sized holes drilled through it. Straighten the warmed
coral as you feed it into a hole of approximately the same size. When
it has cooled (5 minutes) simply push it out the bottom and it will be
straight.

With the awl, make center marks in both ends. Black coral normally
will have a small, soft core running the length of the limb. The core
may be very tiny or a millimeter or more across



and it is not always exactly in the center. When drilling, the drill
will tend to wander into the softer core and your string hole will be
off center, making it difficult to cut an accurate bead. The awl mark
will help start the drill in the center.

With a 1.5mm drill and while holding the coral lightly in a ring clamp
or small hand vise, drill a hole straight into one end about 1/2 the
length. Drill from the other end until the holes meet and then push
the drill the entire way through to clear the hole. When drilling,
use light pressure and do not keep the turning drill in the hole too
long. Drill a little and withdraw it. Drill a bit more and withdraw
it again. This will preclude the coral from becoming hot and distorted
and from “grabbing” the drill. If the coral does grab the drill, do
not try to turn the drill…it will probably break off in the hole.
Wait a minute and try turning the drill again. Usually the coral will
let go as it cools. You might also try reversing the drill. If all
else fails, throw the whole thing, drill and all, into a glass of
water and the next day, the drill will easily come out. Of course now
you must wait for the coral to dry before proceeding.

Place a 150 grit-sanding disc onto the motor spindle. GENTLY push the
pointed rod into one end of the drilled rough bead. If the ground
point of the rod will not fit snuggly into the hole, adjust the point
with a file until it does so. If too tight it could split the end of
the bead, if too loose you will not be able to control the rotation of
the bead against the sanding disc or the polishing wheel.

BEFORE BEGINNING TO SAND, PUT ON YOUR MASK TO PROTECT AGAINST THE
UPCOMING CORAL DUST. ALSO WEAR SAFETY GLASSES TO PROTECT AGAINST A
WAYWARD FLYING BEAD OR PIECE OF CORAL DEBRIS.

(NOTE: It is not recommended that you do this sanding in the house or
anywhere that might be adversely affected by the coral dust or the
smell of cut coral. Both can be irritating to some people and in any
event neither will make you more popular with your spouse, the kids or
your pet!)

If the diameter of the rough bead is not quite round, hold it
lengthwise to the flat disc and quickly turn it 360 degrees, pausing
slightly at the high areas. Then allow the bead to spin in your
fingers against the rotation of the disc to “round it out”. Try not
to remove too much material in this process but seek a relatively even
diameter.

Shape the bead in two stages. First, cut a bevel 2 to 3 mm wide at
approximately 45 degrees back from the hole, leaving a small collar
between the outer edge of the hole and the bevel. Make this bevel
even all the way around the bead. Then “sweeping” the bead against
the disc, round out both the edge of the collar around the hole and
the inside bevel. By sweeping the bead, you should create a smooth
rounded “bullet” shape from the hole back about ¼ of the length of the
bead. Pull the bead off the steel rod and GENTLY push it into the
hole in the other end. Perform the same function on this end rounding
out any lop-sided areas.

Change the 100-grit disc for a 320 or 400 grit disc. Selecting one or
the other will depend on how smooth your first cut is. If it is
nicely rounded and smooth, go directly to the 400. If the bead is
still pretty rough, use the 320, then the 400. Sand the entire bead
again smoothing any ridges and removing sanding marks left by the 100
grit disc until you are satisfied with the shape and surface.

Polish the bead with one of the polishes in the same manner that you
sanded it. Polish first with the muslin wheel perpendicular to the
length of the bead and finish parallel to the length. Whichever
polish you use first, it is always best to finish with ZAM. If, while
polishing, you discover small scratches or uneven areas, unlike when
polishing a stone, you may be able to polish them out. Use medium to
heavy pressure to achieve a perfect polish. But be careful not to use
too much pressure or to stay in one place too long as this will “burn”
the coral in that spot turning it a light brown color. Polish one end
and then switch the bead around on the rod and polish the other.

When you take the bead off the rod, run the 1.5 mm drill through the
bead hole to clear any debris that accumulated during polishing. If
the string hole is slightly off center, flatten the end using the file
and use one of the burrs to shape and smooth the inside shoulder of
the hole. This will re-center the hole and make it easier to string.
As with any black coral jewelry, the beads will loose their polish
with time. But in its place they will take on a satin patina that is
in itself quite lovely. In any event, the coral can be easily re-
polished from time to time.

There are many ways to speed the production of coral beads. The
author uses a motorized miniature drop saw to cut the beads to
length. A one inch belt sander with a 5 inch side disc makes sanding
a breeze and rather than holding the bead in a vice for drilling, he
holds them between his thumb and index finger. This is much quicker
and provides an indication if the bead is becoming too hot during
drilling. But by following the above instructions, you can learn to
make coral beads cheaply and quickly. Later, you can develop
shortcuts to make several dozens at a time. You will also quickly
learn how to make different shapes of beads; rondels, rounds, torpedo
shaped, flat ended, there are many varieties. Happy cutting!