Five-component eutectic fusible alloy, 44.7% Bi / 22.6% Pb / 19.1% In / 8.3% Sn / 5.3% Cd. Melting point 117°F (47°C). Used for lens blocking and tooling aids.
The 117°F (47°C) Low Melting Alloy is a five-component eutectic fusible alloy containing bismuth, lead, indium, tin, and cadmium. Its eutectic composition produces a single sharp melting point at 117°F (47°C) — among the lowest Forms: a metal alloy — with a density of 0.32 lbs/in³ and tensile strength of 5,400 lbs/in². The alloy exhibits slight post-solidification growth that stabilizes within 24 hours.
This alloy is used primarily in the optical industry for lens blocking during the grinding of glass, plastic lenses, and precision optical components. Its extremely low processing temperature ensures that heat-sensitive substrates are not distorted during fixturing. It is also used as a tooling and production aid where an easily castable, low-temperature holding medium is required, and for proof casting applications.
Supplied as 2 lb even-weight cakes measuring 3.5″ x 3.5″ x 1.5″ for consistent charging. The alloy can be recovered and recycled multiple times without significant degradation of properties.
Common technical inquiries regarding 117 F, 47 C Low Melting Alloy
Indium is included in this five-component eutectic to depress the melting point to 117°F — significantly lower than bismuth-tin or bismuth-lead binaries. Indium also improves wetting characteristics and contributes to the alloy's ability to bond to glass and ceramic surfaces, which is important in optical lens blocking applications.
The alloy shows slight growth of 0.0005 in/in within the first 2 minutes after casting, then contracts marginally to -0.0001 in/in at 1 hour and stabilizes at approximately -0.0002 in/in from 24 hours onward. Critical tolerance work should account for this initial growth phase.
Both cadmium and lead are regulated hazardous materials requiring engineering controls including local exhaust ventilation when melting or casting. Operators should follow OSHA standards for cadmium (29 CFR 1910.1027) and lead (29 CFR 1910.1025), use appropriate PPE, and ensure proper waste disposal in compliance with applicable regulations.
Cadmium-free eutectic fusible alloy, 49% Bi / 21% In / 18% Pb / 12% Sn. Melting point 136°F (58°C). Used for lens blocking, tooling, and fusible safety devices.
CAST Metal, 281-338 F, 138-170 C Low Melting Alloy
Bismuth-tin non-eutectic alloy (40% Bi, 60% Sn) with 281-338°F (138-170°C) melting range for lost-pattern casting, proof casting, and low-temperature sealing.
Eutectic fusible alloy, 50% Bi / 26.7% Pb / 13.3% Sn / 10% Cd. Melting point 158°F (70°C). Used for tube bending, work-holding, and fusible safety devices.
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