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Ratio of wax to sterling

Hi All: Is there a fixed ratio of either the weight or volume of a
wax model to the amount of sterling needed to cast it? I seem to
remember something like 1:8 or 1:10 but can’t find my notes. Any
other guidelines that would be helpful? Thanks Sandra


sterling is 10.4 to  1 (usually just use 11)
14k is 13.5 to 1
18k is 15.6 to 1
Brass or bronze is somewhere around 9 to 1

Andy Cooperman

1:10.470 is the weight ratio I use for sterling 1:12.610 for 14kt
white gold and 1:12.610 for 14kt yellow gold . These ratios are for wax
to metal. Frank Goss

Hi Sandra, I was taught that the weight of the wax multiplied by 12
plus about 1/4 oz for the sprue is the ratio to use. It works for
me but I vacuum cast using a handy melt so the ratio is not critical
as it would with centrifugal casting. Your orchid friend Lee Epperson

Hi Sandra, The conversion from wax to sterling is 1 to 10. I double
checked specific gravities in Oppi Untracht’s book: wax has a SG of
.95-.98 and sterling is 10.4. I know this wasn’t in your question, but
I thought it might be helpful to those who carve a lot of waxes. I
use my carat scale to weigh the waxes I’m carving and with a little
high school math figured out the conversion: carat weight x .1286
equals dwts. That obviously gives you the weight of the wax. Then I
went a step further and multiplied .1286 by the specific gravity of
the metal to be used. For example, the SG of 14K yellow is 13.07, so
I multiply 13.07 by .1286 which equals 1.68. Personally I round it up
to 1.8. Sooooooooooo, when I plunk my wax on the carat scale, I
simply take the carat weight figure on the scale (say, 2.5 for an
average ring for example) and multiply it by 1.8 and that immediately
gives me a good idea of what it would weigh in gold (not including
sprue). To simplify: -for 14K yellow: multiply weight of wax in carats
by 1.8 -for 18K yellow: multiply by 2.0 -for platinum in general:
multiply by 2.8 or so -for Sterling Silver: multiply by 1.3 Maybe
others have found conversion numbers they prefer, but this works for


Dear Sandra

 Is there a fixed ratio of either the weight or volume of a wax
model to the amount of sterling needed to cast it? .... 

I learned that the correct ratio is 1:11 (by weight) and this ratio
works well for me.

Kind regards
Niels L=F8vschal, Rutsker, Denmark

I put together a small spread sheet, Flask.Xls to calculate the
investment and the metal for a job. I got tired of setting with the
calculator every time I needed to cast. I just make the entrees and
then print out the sheet and clip it to the front of my vacuum unit.

The spread sheet can be downloaded at Just chose the Flask.XLS
file to download.