Cerrosafe

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.[1][2]

Similar metals

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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

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  1. ^ "Brownells Cerrosafe® Chamber Casting Alloy". Archived from the original on September 18, 2017. Retrieved September 18, 2017.
  2. ^ "CS Alloys Safe 165, Cerrosafe". Retrieved September 18, 2017.
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