Cerrosafe is a fusible alloy with a low melting point. It is a non-eutectic mixture consisting of 42.5% bismuth, 37.7% lead, 11.3% tin, and 8.5% cadmium that melts between 70 °C (158 °F) and 88 °C (190 °F). It is useful for making reference castings whose dimensions can be correlated to those of the mold or other template due to its well-known thermal expansion properties during cooling. The alloy contracts during the first 30 minutes, allowing easy removal from a mold, then expands during the next 30 minutes to return to the exact original size. It then continues expanding at a known rate for 200 hours, allowing conversion of measurements of the casting back to those of the mold.
Similar metals
| Alloy | Melting point | Eutectic? | Bismuth % |
Lead % |
Tin % |
Indium % |
Cadmium % |
Thallium % |
Gallium % |
Antimony % |
|---|---|---|---|---|---|---|---|---|---|---|
| Rose's metal | 98 °C (208 °F) | no | 50 | 25 | 25 | – | – | – | – | – |
| Cerrosafe | 74 °C (165 °F) | no | 42.5 | 37.7 | 11.3 | – | 8.5 | – | – | – |
| Wood's metal | 70 °C (158 °F) | yes | 50 | 26.7 | 13.3 | – | 10 | – | – | – |
| Field's metal | 62 °C (144 °F) | yes | 32.5 | – | 16.5 | 51 | – | – | – | – |
| Cerrolow 136 | 58 °C (136 °F) | yes | 49 | 18 | 12 | 21 | – | – | – | – |
| Cerrolow 117 | 47.2 °C (117 °F) | yes | 44.7 | 22.6 | 8.3 | 19.1 | 5.3 | – | – | – |
| Bi-Pb-Sn-Cd-In-Tl | 41.5 °C (107 °F) | yes | 40.3 | 22.2 | 10.7 | 17.7 | 8.1 | 1.1 | – | – |
| Gallium | 30.0 °C (86 °F) | Pure metal | - | - | - | - | - | - | 100 | – |
| Galinstan | −19 °C (−2 °F) | no | <1.5 | – | 9.5–10.5 | 21–22 | – | – | 68–69 | <1.5 |
References
- "Brownells Cerrosafe® Chamber Casting Alloy". Archived from the original on September 18, 2017. Retrieved September 18, 2017.
- "CS Alloys Safe 165, Cerrosafe". Retrieved September 18, 2017.
External links
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