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Wax to Cast Gold Conversions


#1

I am trying to find a sauce for what the industry uses for
converting wax to cast gold - 9kt, 10kt, 14kt, 18kt & 22kt. Is there
anyone out there is a good source for this Seems like
every factory has their own version of this …all very
close, but no basis for the differences.

Cindy Groover


#2

Cindy,

the calculation of the metal weight is straightforward and very
simple:

the volume you want to fill with metal is previously filled with
wax, therefore the volume to be filled remains the same.

If you know the density (sometimes referred to as specific gravity)
of the wax G(w) you’re using and you measure the mass of your total
(button, main sprue, sprues and models) wax M(w) then the Volume is:

V=M(w)/G(w)

which is the same volume for the metal.

With the specific gravity of your metal G(m) and the mass of the
metal M(m) the Volume is:

V=M(m)/G(m).

For the volume to be filled remains the same the ratio of M(m)/G(m)M
equals (w)/G(w). Therefore the Mass M(m) of metal needed is:

M(m)=M(w)/G(w)*G(m).

This applies for all waxes and all metals.

The density of your waxes and metals you may obtain from your
supplier or calculate by yourself.

Sandor Cser,
Ti-Research GbR


#3

Density -

wax 0.95
stg sil 10.4
9ct rose 10.8
9ct yellow 11.4
9ct white [med] 12.8
10ct yellow 11.6
14ct yellow 15.2
14ct white 14.3
18ct yellow 16.3??
22ct yellow 19.4??
platinum 21.43

To convert one alloy to another - divide weight by the known alloy
density and then multiply by the wanted alloy density.

CjH


#4

Cindy,

Weigh the wax pattern with sprues attached and then multiply it x
the specific gravity of the metal you will use and then add anywhere
from 25% to 50% extra for the button.

The specific gravity of the following metals may help:

  Karat      Color            Specific Gravity
  18          green           15.9
  18          yellow          15.58
  18          white           14.64
  18          red              15.18

  14          green           14.2
  14          yellow          13.07
  14          white           12.61
  14          red              13.26

  10          green           11.03
  10          yellow          11.57
  10          white           11.07
  10          red              11.59

  pure silver                  10.53
  sterling silver              10.40
  coin silver                  10.35

Hope that helps
Greg DeMark
email: greg@demarkjewelry.com
Website: http://www.demarkjewelry.com
Custom Jewelry - Handmade Jewelry - Antique Jewelry


#5
To convert one alloy to another - divide weight by the known alloy
density and then multiply by the wanted alloy density.

I would add that 95 palladium is 12.3

Daniel Ballard