I am curious as to the method and procedure of stone in casting for
diamonds as well as color.
Thx, Don
I may be treading some peoples toes and if they dont approve of some
of my facts, they can correct me via email …but here goes the
method I use and teach when I set stones in wax!
I only set stones such as Ruby, Sapphires, Diamonds (any with
minimal inclusions) “Thou shalt not set or use any other kind of
stones”…The harder they are on the Mohs scale, the better…! Do not
wax set with stones less than 9.0. What I initially do is with a
simple round bur, size of the widest part of the pavilion hand rotate
the bur, so the stone will sit on the wax that is touching this
pavillion.
Let the stone sit “ON”, not “in” the wax impression. I use a blue
wax that is similar to plastic. That is, when you press the stone in,
the wax expands and allows the stone to feel its own level and then
the wax will return to its original position.
I also use a rheostat-heating model makers tool tip with a little
curved blade and then heat up the stone only enough to settle the
stone into the wax. The “sinking heated stone” will form a little
edge (Meniscus Curve) around the girdle of the stone, …the stone
will now displace some wax and “then this wax” when casted, will then
"hold" the stone…I have been asking casters around this city about
the temperature of the gold with stones in…they say drop the
temps. only 100-150 F. MAX.!!!
DO NOT RAPID-COOL AFTER CASTING, let the hot flask cool on cement
floor, or put it immediately back into the cooling furnace…I have
seen so many stones break and once, 10 carats of diamonds shatter
when the rapid cooling was attempted, a real ugly and expensive
sight. enjoy, enjoy!..I hope this helped you…Gerry!
Continue from:
DO NOT RAPID-COOL AFTER CASTING, let the hot flask cool on cement floor, or put it immediately back into the cooling furnace...I have seen so many stones break and once
I have only cast with diamonds in place a couple of times. A huge
error that I made one time was to set stones so close in a channel
that they actually touched. Slow cooling didn’t help them in this
case. I suggest that one leave a gap .1mm wide between the stones
for better results
bruce
Bruce Holmgrain
http://www.goldwerx.com
Well, big topic. I suggest you read
http://preciousmetalswest.com/stonein.htm
And similar articles that can be found in AJM. August issue from a
couple years ago.
In a nutshell, this is a mass production method, in general not as
well suited to designer “one off” pieces. The size of the setting,
prongs, channel, and all is critical to the size of the stones.
Shrinkage calculations must be right on the money. Ideally, Plan on
special alloy; low flow temp, high fluidity (high zinc at least) call
an alloy guy for more detail. Plan on a special investment or
additive to protect the stones. . Burnout never really happens, its
more like a “warm out” 
to be gentle to the stones. You must not
quench-stones hate thermal shock. Stone in place casting is one
reason lasers grew in popularity so fast. These stone in casting are
well worth fixing recasting is problematic cost wise. The best thing
stone in does to the average caster is to get all those niggling
variables controlled. Like precise measures of investment powder,
water volume and temperature control in every way. This makes all
the castings better.
Daniel Ballard
Don,
AJM magazine has published many articles on this technique over the
years. You can order copies of them even if you are not a member:
There is a $5 per article fee for non-members. You can order copies
via the Web site at www.ajm-magazine.com.
I don’t find AJM’s article index as easy to navigate as the older
version, but this is a sufficiently common topic you can use the
site’s “search by topic” feature, which will give you all the
articles since 1997. There were others earlier: if you need to track
them down, your best bet is to call an MJSA member service rep and
ask for their help.
Good luck!
Suzanne
Suzanne Wade
Writer/Editor
Phone: (508) 339-7366
Fax: (928) 563-8255
@Suzanne_Wade1
http://www.rswade.net
Hi,
An important point is that minimum wax (later transformed to metal)
must hold the stone securely from the top and bottom to reduce heat
transfer and keep open for good look.
If you do only small quantity, you may take the impression in wax.
If the stone is over 2.5 mm, the net shrinkage of about 1/2 to 1%
during casting – expansion of investment and reduction of metal–
matters.
Especially for larger stones, over 6 mm, you may not want to cast,
but make only a good seat to help set in metal. It makes sense to use
a Teflon tape below the stone and heat the stone with a small wax
solder pen to get a good seat. Then, you may remove the tape, stone
and clean the melted wax.
After casting, hardly any work will be needed to set.
Regards
Shishir Nevatia
Sunjewels
Seepz Mumbai India 400096
Fax +9122 2829 0206 or
+9122 5691 9739
When you cast in place, after the cool down, submerge in water and
re-vacuum under water. The investment comes out in slurry. This way
you don’t need to dig it out.
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