Copper to Copper Brazing Rod

Copper-to-copper brazing is the most common and widely used connection method in refrigeration and air conditioning (HVAC), electrical power, home appliances, and piping systems. Compared to brazing dissimilar metals, copper-to-copper connections are simpler and more economical, and offer high joint strength, good sealing, and excellent electrical and thermal conductivity.

Chalco's copper-to-copper brazing electrodes are based on phosphorus-copper alloys, with some series incorporating silver to enhance toughness and corrosion resistance. All products offer significant advantages.

• Simple process: Most alloys have self-fluxing properties, requiring no additional flux, and welding is efficient and reliable.
• Excellent performance: The connector is pressure resistant and leak-proof, while maintaining the high electrical and thermal conductivity of copper.
• Flexible options: from economical silver-free to high-performance silver-containing series, to meet different application needs.

With our complete BCuP series, you can flexibly choose between cost and performance to obtain the most suitable copper-copper welding solution.

Chalco Copper Brazing Materials Product Series – Copper-Copper Joint Welding Electrode Alloy

Chalco offers a complete range of copper-to-copper brazing electrodes, ranging from economical silver-free phosphor bronze alloys to high-performance silver-containing alloys, meeting the diverse needs of HVAC refrigeration, electrical power, appliance piping, and industrial systems. Through a balanced blend of silver contents, our BCuP series offers optimal value in terms of ease of use, joint reliability, and service life.

BCuP-2 – Phos-Copper Brazing Alloy, No Silver

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  It contains phosphorus and is silver-free, possesses self-fluxing properties, and requires no additional flux for copper-to-copper brazing.

  It has the lowest cost, good liquidity, and is suitable for large-scale standard applications.

  It cannot be used on steel or nickel alloys (phosphorus will cause embrittlement).

Typical applications: HVAC refrigeration copper tubing, heat exchangers, and copper tubing for household appliances.

Technical Specifications:

BCuP-3 / BCuP-6 – Phos-Copper-Silver Brazing Alloys, Low Silver

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  Adding 2–5% silver to the phosphorus-containing base results in better fluidity than the silver-free type.

  Improve the toughness and corrosion resistance of the joint.

  It performs better in applications with low to medium vibration or where certain fatigue requirements exist.

Typical applications: appliance piping, copper valves, and light vibration conditions.

Technical Specifications:

BCuP-4 – Phos-Copper-Silver Brazing Alloy, Medium Silver

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  It contains about 7% phosphorus and about 6% silver, resulting in stronger wettability and denser welds.

  The connector has better durability than low-silver products.

  It balances cost and performance, making it a versatile high-performance option for copper-to-copper brazing.

Typical applications: refrigeration equipment, electrical contacts, and copper piping systems for drinking water.

Technical Specifications:

BCuP-5 – Phos-Copper-Silver Brazing Alloy, High Silver

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  It contains approximately 5% phosphorus and up to 15% silver.

  The joint exhibits optimal toughness and fatigue resistance, making it suitable for high-end applications.

  It has a high cost, but its cost-effectiveness is outstanding in key components.

Typical applications: motor coils, aerospace electrical systems, copper-copper connections in environments with strong vibration and high pressure.

Technical Specifications:

Chalco’s copper-to-copper brazing electrode series, ranging from the economical BCuP-2 to the high-performance BCuP-5, covers all major applications including HVAC, home appliances, electrical systems, and industrial systems. In addition to these alloys, Chalco also provides a wide range of other brazing rods and brazing consumables to support different welding processes, which you can explore in the product list below.

Aluminum Brazing Rod

Flux-core Aluminum Brazing Rod

Aluminum Stick Welding Rod

Silver Brazing Solder Rod

Copper Brazing Rod

Brazing Ring Preforms

Chalco Copper to Copper Brazing Rods : Application Scenarios and Selection Recommendations

Chalco's copper-to-copper brazing electrodes have a wide range of applications in HVAC refrigeration, electrical power, drinking water and gas systems. By selecting appropriate alloys, from economical silver-free to high-performance silver-containing alloys, an optimal balance between cost and performance can be achieved.

HVAC & Refrigeration Systems

Copper-to-copper brazing electrodes are most widely used in the welding of pipes in air conditioners , condensers, evaporators, and heat exchangers. The joints require high airtightness and pressure resistance to ensure long-term stable operation of the system.

Recommended alloy:

BCuP-2 → An economical option suitable for large-volume standard copper pipe connections.

BCuP-3 → Improves connector life and corrosion resistance, suitable for high-reliability refrigeration systems.

Electrical and power systems

Conductivity and contact reliability are critical indicators in the welding of busbars , copper contacts, coil terminals , and electrical joints. Copper-to-copper brazing electrodes maintain low resistance and high conductivity, ensuring long-term stable operation of equipment.

Recommended alloy:

BCuP-4 → High weld density, suitable for electrical contact and busbar connection.

BCuP-5 → High strength and fatigue resistance, suitable for high-end applications such as motors and aerospace electrical systems.

Piping and Gas Distribution

Drinking water, gas, and industrial piping systems require safe, sealed, and durable joints. Copper-to-copper brazing electrodes offer excellent leak resistance and corrosion resistance in these applications.

Recommended alloy:

BCuP-3 → Balanced performance, suitable for piping installations and residential systems.

BCuP-4 → The weld seam is denser, making it suitable for high-standard drinking water and gas pipeline systems.

Whether it's copper piping for refrigeration systems, high-reliability connectors for electrical busbars, or sealing welds for drinking water and gas pipelines, Chalco offers a full range of copper-copper brazing electrode solutions, from silver-free to high-silver. Contact us for suitable alloy recommendations, quick quotes, and sample support.

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Process Guidelines and Operating Recommendations – Copper to Copper Brazing Rods

While copper-to-copper brazing is a simple process, achieving high-quality joints still requires adherence to proper operating procedures. The following are key process considerations recommended by Chalco:

Heating method

• Flame brazing: Use a neutral or slightly reducing flame to heat the copper tube evenly until the brazing filler metal is just bright and flowing.
• Induction brazing: Heating rate 20–40 ℃/s, hold for 2–3 seconds after penetration to avoid overheating.
• Furnace brazing: Uniform heating is controlled within the recommended temperature range, suitable for batch production of copper tube assemblies.

Brazing gap

• The recommended range is 0.03–0.08 mm to ensure sufficient capillary action.
• Excessive gaps will lead to decreased strength, while insufficient gaps will make wetting difficult.

Surface preparation

• Remove oil and oxide film before welding to keep the copper tube surface clean.
• Mechanical polishing or chemical cleaning is recommended to improve wettability.

Heating and cooling

• When heating, avoid concentrating the heating on the welding wire; the base material should be heated first.
• During the cooling phase, natural cooling is preferable to avoid sudden cooling that could cause the joint to crack.

Common defects and solutions

FAQ of purchasing copper to copper aluminum brazing rod

Q1: Is flux always unnecessary for copper-to-copper brazing?

Most phosphorus alloys (such as BCuP-2 to BCuP-5) exhibit self-fluxing properties in copper-to-copper joints, eliminating the need for additional flux. However, when welding copper alloys or workpieces with severe surface oxidation, flux is recommended to improve wetting.

Q2: How to choose between silver-containing and non-silver-containing welding rods?

• Silver-free type (such as BCuP-2): Low cost, suitable for mass welding of standard copper pipes.
• Silver-containing types (such as BCuP-3/4/5/6): offer better toughness and corrosion resistance, making them suitable for vibration, fatigue, or high-reliability applications.

Q3: Can copper-to-copper welding rods be used for copper-to-brass or copper-to-steel connections?

Not recommended. Phosphorus can cause embrittlement of iron and nickel-based alloys. For copper-to-brass, copper-to-steel, or copper-to-aluminum connections, please refer to the corresponding solutions on the Copper to Aluminum Brazing Rod or Copper Brazing Rod page.

Q4: What are the differences between copper-to-copper brazing and other methods?

• vs. copper-aluminum brazing: Copper-copper process is simpler, has stronger self-fluxing properties, and lower process costs.
• vs. silver brazing (pure silver BAG series): Copper-copper brazing electrodes are more suitable for mass copper pipe assembly; silver brazing is more suitable for dissimilar metals and critical components.

Chalco copper to copper brazing rod product supply and specifications

Chalco offers a diverse range of copper-to-copper brazing electrodes, providing customers with flexible options for different operating conditions:

Supply forms: straight bar, coiled bar, cored type, coated type.

Size range: 1.5 mm – 6.0 mm in diameter, special specifications can be customized upon request.

Packaging methods: small packages, rolls, cartons or wooden crates for export, ensuring safe transportation.

Execution standards: Compliant with international standards such as AWS A5.8 and ISO 3677 , and provide complete material certification.

Delivery and Service: Common specifications are in stock, and we support fast delivery and sample requests. OEM customization services are also available.

Looking for a reliable copper-to-copper brazing electrode supplier?

Chalco offers a complete BCuP series, from silver-free to high-silver, enabling efficient welding of HVAC, electrical, and industrial piping systems.

Contact us today for a quote and samples, or for expert selection advice.