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SN42/BI58 LEAD-FREE SOLDER PASTE
Features
- Lead-Free Eutectic Alloy
- Low Melting Point 138°C (280°F)
- No-Clean Halide-Free Flux (IPC J-STD-004 ROL0)
- Type 4 Powder (20–38 μm) per IPC J-STD-005
Description
Sn42/Bi58 is composed of 42% tin and 58% bismuth, formulated as a no-clean Type 4 solder paste for low-temperature reflow assembly. Typical applications include second-stage reflow for circuit board assembly, attachment of heat-sensitive components, flexible PCBs (FPC), LED arrays, and hand dispensing or rework where peak temperatures must remain below 170°C. Sn42/Bi58 has a eutectic melting point of 138°C (280°F).
Impurity Levels to IPC-J-STD-006 in Percent
| Ag: 0.05 | Pb: 0.10 | Cu: 0.08 | In: 0.10 |
| Al: 0.005 | Au: 0.05 | Sb: 0.05 | Ni: 0.01 |
| As: 0.03 | Cd: 0.08 | Fe: 0.02 | Zn: 0.003 |
Major Alloy Ingredients in Percent
| Sn | Bi |
|---|---|
| Sn: 42 ± 0.5 | Bi: 58 ± 0.5 |
Properties
| Properties | Results |
|---|---|
| Electrical Conductivity (1.72 µΩ-cm) % of IACS | 4.5 |
| Thermal Conductivity @ 85°C W/cm-°C | 0.19 |
| Coefficient of Thermal Expansion @ 20°C PPM/°C | 15 |
| Tensile Strength PSI | 8,000 |
| Shear Strength PSI | 500 |
| Elongation % | 55 |
| Brinell Hardness | 23 |
| Latent Heat of Fusion J/g | 44.8 |
| Density g/cc | 8.72 |
Handling & Storage
Store refrigerated at 2–10°C (36–50°F). Do not freeze. Shelf life is 6 months from date of manufacture when stored unopened in original container. Allow 1–2 hours at room temperature (20–25°C) for the syringe to reach operating temperature before use. After opening, store upright in refrigerator; best used within 2 weeks. Consult the Safety Data Sheet for specific handling procedures.
Flux
tinvoa Sn42/Bi58 solder paste contains an integrated synthetic no-clean flux classified as ROL0 per IPC J-STD-004 (Rosin base, Low activity, Halide-free). Halide content is below detectable limits. Metal content is approximately 88.5% by weight.
Cleaning
No cleaning required. The no-clean flux residue is non-conductive and non-corrosive and may remain on the assembly. If cleaning is desired for aesthetic or coating reasons, use an IPA-based solvent.
Safety
Use with adequate ventilation and proper personal protective equipment. Classified as H410 — Very toxic to aquatic life with long lasting effects (GHS09). Not regulated under DOT, ICAO-IATA, or IMDG. California Proposition 65 Warning: Cancer and Reproductive Harm — www.P65Warnings.ca.gov. Refer to the accompanying Safety Data Sheet (SGS Report EECSSDS2605112401) for emergency information. Do not dispose of any hazardous materials in non-approved containers.