Harris 50/50 Leaded Bar Solder (part number 50501B) is a general-purpose 50% tin / 50% lead bar solder for non-potable metal joining, sheet metal work, and general industrial soldering applications. The 1 lb bar format is convenient for torch soldering, dip soldering pots, and iron applications. 50/50 tin-lead solder has been a staple of the trade for generations, prized for its wide plastic range — the mushy consistency between solidus and liquidus that allows the operator to shape a joint before it solidifies. This characteristic makes 50/50 particularly useful for wiped-lead joints, large-area fills, and vertical joints where the alloy must be held in position briefly while cooling. Note: 50/50 solder contains lead and is not approved for use on potable water systems under the Safe Drinking Water Act. Use Harris lead-free solder (331762 silver bearing or Stay-Brite 8) for all drinking water applications.
| Property | Value |
|---|---|
| Composition | 50% Tin (Sn) / 50% Lead (Pb) |
| Solidus | 361 °F (183 °C) |
| Liquidus | 421 °F (216 °C) |
| Plastic Range | 60 °F (33 °C) — wide, ideal for wiped joints |
| Form | Bar |
| Weight | 1 lb |
| Part Number | 50501B |
| Lead Content | 50% — NOT for potable water use |
| Tensile Strength | Approx. 3,500–4,000 psi |
| Heat Sources | Soldering iron, soldering gun, air-fuel torch |
- Sheet metal work — filling and seaming non-galvanized sheet metal, automotive body work (where lead-free codes do not apply), HVAC duct seaming in non-potable applications
- Plumbing — non-potable water only — drain, waste, and vent (DWV) cast iron soil pipe (oakum and lead caulked joints), industrial wastewater lines, and laboratory drainage systems where lead restrictions do not apply
- Electrical and electronics (legacy applications) — large component through-hole soldering, terminal blocks, and bus wire connections in industrial control panels where RoHS compliance is not required
- Wiped lead joints — traditional lead plumbing maintenance on heritage buildings and historical restoration where original lead-work is being repaired
- Radiator and heat exchanger repair — filling and seaming copper radiator tanks and cores in automotive and industrial radiator shops
- Dip soldering pots — suitable for use in wave solder or dip solder pots for non-RoHS production
Unlike single-melting-point alloys (such as eutectic 63/37 tin-lead at 361 °F), 50/50 solder passes through a mushy plastic state between 361 °F (solidus) and 421 °F (liquidus). In this plastic range, the alloy can be wiped, shaped, or pushed into gaps before final solidification. This property is essential for wiped lead joints in traditional plumbing and for filling irregular gaps in sheet metal work. Use this property intentionally — keep the iron or torch moving after alloy application to maintain the plastic state during shaping, then remove heat to allow clean solidification.
50/50 bar solder is a bare alloy with no flux core. Apply a separate rosin-core or paste flux appropriate for the base metal before soldering. For copper and brass, a liquid or paste zinc chloride flux provides good wetting. For tin-plated surfaces, a mild rosin flux is sufficient. Remove all flux residue after soldering to prevent corrosion — especially important in closed or hidden assemblies.
- 50/50 (this product) — widest plastic range, best for wiped joints and large-area fills. Lower tensile strength. NOT for potable water.
- 95/5 Tin-Antimony — stronger, higher service temperature (~450 °F), can be used on some non-potable plumbing. More brittle than 50/50.
- Lead-free (Harris 331762 or Stay-Brite 8) — required for potable water, food service, and RoHS compliance. Slightly higher melting temperature.
- Can 50/50 solder be used on drinking water pipes?
- No — contains 50% lead. Use Harris lead-free silver bearing solder (331762) or Stay-Brite 8 (SB861) for all potable water applications.
- What is the melting temperature of 50/50 solder?
- Solidus 361 °F (183 °C); liquidus 421 °F (216 °C). Wide plastic range ideal for wiped joints and large-area fills.
- What flux is needed?
- No flux core — apply separately. Use zinc chloride flux for copper/brass, rosin paste for tin-plated surfaces. Remove all residue after soldering.
- What is 50/50 solder typically used for?
- Sheet metal work, radiator repair, wiped lead plumbing joints, non-potable plumbing, and general industrial soldering where lead is not restricted.
Browse the full solder and brazing alloy collection. For lead-free options see Harris Silver Bearing Lead-Free Plumbing Solder (331762) and Harris Stay-Brite 8 (SB861). Reference: Harris Products Group.