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

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

me!

Cindy

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

http://webpages.charter.net/campgems/Flask/ Just chose the Flask.XLS

file to download.

Don