Specific Gravities of
Alloys
1.
Find
the reciprocal of the specific gravity of each metal in the alloy. This is done
by dividing 1 by the specific gravity. For example, the specific gravity of
silver is 10.49 and the reciprocal is 1 divided by 10.49 or .094966.
2.
Multiply
each reciprocal by the number of parts per thousand of that metal to be used.
3.
Add
the results of the multiplications together.
4.
Divide
1,000 by this total‑the answer is the specific gravity of the alloy.
Example
Find the specific gravity of 14K yellow gold having
583
parts gold, 104 parts silver and 313 parts copper.
First
figure the reciprocals of the specific gravities.
Fine Gold ‑ 1 divided
by 19.32=.051759
Fine Silver ‑ 1 divided
by 10.49=.094966
Fine Copper ‑ 1 divided
by 8.96=.111617
Then multiply
Fine Gold ‑583
parts by weight X.051759=30.182
Fine Silver
‑104 parts by weight X .094966= 9.876
Fine Copper ‑313 parts by weight
X.111617=34.956
Totals 1000 75.014
1000 divided by 75.014=13.33, the specific gravity
of the alloy.
*The
specific gravity for any one karat will naturally vary for each composition.
TABLE 4
Specific Gravity, Melting Point, and
Weight of Various Metals and Alloys
|
|
Melting Point |
|
Weight |
|
|
|
|
|
Specific |
in Tr. Ozs. |
|
Metal |
°F |
°C |
Gravity |
per Cu. In. |
|
Aluminum |
1220 |
660 |
2.70 |
1.423 |
|
Antimony |
1167 |
630 |
6.62 |
3.488 |
|
Beryllium |
2340 |
1282 |
1.82 |
.959 |
|
Bismuth |
520 |
271 |
9.80 |
5.163 |
|
Cadmium |
610 |
321 |
8.65 |
4.557 |
|
Carbon |
- |
- |
2.22 |
1.170 |
|
Chromium |
3430 |
1888 |
7.19 |
3.788 |
|
Cobalt |
2723 |
1495 |
8.90 |
8.90 |
|
Copper |
1981 |
1083 |
8.96 |
4.719 |
|
Gold |
1945 |
1063 |
19.32 |
10.180 |
|
18
K green |
1810 |
988 |
15.90 |
8.375 |
|
18
K yellow |
1700 |
927 |
15.58 |
8.211 |
|
18
K white |
1730 |
943 |
14.64 |
7.712 |
|
18
K red |
1655 |
902 |
15.18 |
7.998 |
|
14
K green |
1765 |
963 |
14.20 |
7.482 |
|
14
K yellow |
1615 |
879 |
13.07 |
6.885 |
|
14
K white |
1825 |
996 |
12.61 |
6.642 |
|
14
K red |
1715 |
935 |
13.26 |
6.986 |
|
10
K green |
1580 |
860 |
11.03 |
5.810 |
|
10
K yellow |
1665 |
907 |
11.57 |
6.096 |
|
10
K white |
1975 |
1079 |
11.07 |
5.832 |
|
10
K red |
1760 |
960- |
11.59 |
6.106 |
|
Iridium |
4449 |
2454 |
22.50 |
11.849 |
|
Iron
(pure) |
2802 |
1539 |
7.87 |
4.145 |
|
Lead |
621 |
328 |
11.34 |
5.973 |
|
Magnesium |
1202 |
650 |
1.74 |
.917 |
|
Manganese |
2273 |
1245 |
7.43 |
3.914 |
|
Molybdenum |
4760 |
2625 |
10.20 |
5.347 |
|
Nickel |
2651 |
1455 |
8.90 |
4.691 |
|
Osmium |
4892 |
2700 |
22.50 |
11.854 |
|
Palladium |
2831 |
1555 |
12.00 |
6.322 |
|
Phosphorus |
111 |
44 |
1.82 |
.959 |
|
Platinum |
3224 |
1773 |
21.45 |
11.301 |
|
15%
Iridio Plat. |
3310 |
1821 |
21.59 |
11.373 |
|
10%
Iridio Plat. |
3250 |
1788 |
21.54 |
11.349 |
|
5%
Iridio Plat. |
3235 |
1779 |
21.50 |
11.325 |
|
Rhodium |
3571 |
1967 |
12.44 |
6.553 |
|
Ruthenium |
4500 |
2500 |
12.20 |
6.428 |
|
Silicon |
2605 |
1430 |
2.33 |
1.247 |
|
Silver |
1761 |
961 |
10.49 |
5.525 |
|
Sterling |
1640 |
893 |
10.36 |
5.457 |
|
Coin |
1615 |
879 |
10.31 |
5.430 |
|
Tin |
450 |
232 |
7.30 |
3.846 |
|
Zinc |
787 |
419 |
7.13 |
3.758 |