Harris Silver Bearing Lead-Free Solid Wire Plumbing Solder (part number 331762) is a professional-grade, NSF-compliant lead-free solder formulated specifically for copper and copper-alloy plumbing joints in potable water, hot water heating, and general plumbing systems. Available in 0.118 in (3.0 mm) diameter wire on a large 25 lb box, this bulk format is designed for plumbing contractors, wholesale distributors, and shops with high daily solder consumption. The silver-bearing composition provides a joint strength and service temperature that exceeds standard tin-only lead-free solders, making it the preferred choice for pressurized domestic water lines, solar thermal systems, and hydronic heating loops. The lead-free formula meets Safe Drinking Water Act requirements and complies with EU REACH and RoHS directives. Melting temperature: 430 °F (221 °C) — compatible with standard soldering irons, propane torches, and MAPP gas torches. Use with a lead-free plumbing flux for best results.
| Property | Value |
|---|---|
| Product Type | Lead-free silver-bearing plumbing solder |
| Form | Solid wire (no flux core) |
| Wire Diameter | 0.118 in (3.0 mm) |
| Package Weight | 25 lb box |
| Part Number | 331762 |
| Melting Temperature | 430 °F (221 °C) |
| Lead Content | Lead-free (0.2% max per Safe Drinking Water Act) |
| Silver Content | Silver-bearing (improves strength and wetting) |
| Flux Requirement | Yes — use compatible lead-free plumbing flux |
| Applicable Standards | Safe Drinking Water Act; EU REACH; RoHS |
| Base Metal Compatibility | Copper, brass, bronze (plumbing applications) |
- Potable water plumbing — lead-free formula meets Safe Drinking Water Act 0.2% maximum lead requirement; approved for drinking water copper piping per most local plumbing codes
- Hot water heating systems — hydronic baseboard, radiant floor, and boiler distribution copper piping operating up to 250 °F service temperature
- Solar thermal systems — collector loop copper piping requiring a solder with better service temperature performance than tin-bismuth alloys
- General plumbing — drain, waste, and vent (DWV) copper joints, fixture supply lines, and pressure test assemblies
- Wholesale and distribution — 25 lb bulk box for plumbing supply houses, mechanical contractors, and institutional facilities departments
- Water heater connections — soldering copper supply and return connections on residential and commercial tank and tankless water heaters
Harris Silver Bearing Solder 331762 is a solid wire — no flux core. Apply a water-soluble lead-free plumbing flux (such as Harris Stay Clean liquid flux or a compatible paste flux) to the cleaned joint surfaces before assembly and heating. Heat the fitting with a propane or MAPP gas torch until the flux bubbles and clears, then feed solder into the joint gap from the side opposite the flame. Capillary action draws the molten solder through the joint. Wipe with a damp cloth while still warm to remove flux residue; flush with water after installation.
Tin-copper and tin-silver-copper (SAC) lead-free solders have replaced the traditional 50/50 and 95/5 tin-lead solders in plumbing codes. The silver-bearing composition in Harris 331762 offers two key advantages over basic tin-copper solder:
- Improved joint strength — silver significantly increases the tensile and shear strength of the tin-based solder matrix, producing joints that outperform standard lead-free solders in pressure testing
- Better wetting on copper — silver reduces surface tension, allowing the molten solder to flow more completely into tight joint gaps and produce more consistent, void-free joints
Lead-free solder (melting at 430 °F) is appropriate for most standard plumbing applications including potable water, domestic hot water, and low-pressure heating systems. For applications above 250 °F service temperature, higher system pressures, or any joint involving steel or dissimilar metals, consider brazing with Harris Stay-Silv 15 (BCuP-5) or Safety-Silv 45 (BAg-5) which provide significantly higher joint strength and operating temperature capability. Your local plumbing code specifies which joining method is required for each application.
- Is this solder safe for potable water?
- Yes — lead-free formulation meets Safe Drinking Water Act requirements. Suitable for drinking water copper plumbing per most local codes.
- What flux is needed?
- Use a compatible lead-free plumbing flux (e.g., Harris Stay Clean or ASTM B813 paste flux). The wire is solid — no flux core. Remove residue after soldering.
- What is the melting temperature?
- 430 °F (221 °C) — compatible with propane and MAPP torches.
- Solder vs. braze — which do I need?
- Solder for standard domestic water and heating up to ~250 °F. For higher temperatures, pressures, or copper-to-steel joints, use Harris Stay-Silv 15 (BCuP-5) or Safety-Silv 45 (BAg-5) brazing alloy.
Browse the full solder and brazing alloy collection. Compare to Harris Stay-Brite 8 lead-free solder (SB861) for a higher-silver option with a plastic soldering range, and the Harris Stay-Silv 15 BCuP-5 brazing alloy for copper applications requiring higher joint strength. Reference: Harris Products Group.