Matweld Welding Rods Copper Flow 2mm M020

Matweld M020 (often referred to as Copper Flow or Low-Fuming Bronze) is a high-quality deoxidized copper-alloy brazing rod. Unlike the welding electrodes previously discussed, these are not "stick rods" for an arc welder; they are filler rods used with an Oxy-Acetylene or Oxy-LPG torch. They are designed for "braze-welding" where the base metal is heated to a dull red, but not melted.

Technical Specifications

• Rod Diameter: 2.0mm.
• Classification: AWS A5.8 RBCuZn-C.
• Composition: Copper-Zinc alloy with added Silicon and Manganese (to control fuming and increase strength).
• Melting Point: Approximately 870°C to 890°C.
• Tensile Strength: Up to 450 MPa (depending on the base metal and joint fit-up).
• Pack Size: Typically available in 1kg or 5kg tubes.

Key Features

• Low Fuming: Formulated with specific deoxidizers that minimize the release of zinc-oxide fumes (the "white smoke" that causes metal fume fever), making it safer for the operator in well-ventilated areas.
• High Fluidity: Excellent "wetting" action allows the molten alloy to flow smoothly into tight joints and over large surface areas.
• Dissimilar Metal Joining: One of the most versatile rods available; it can join steel to cast iron, copper to steel, and brass to copper.
• Machinability: The resulting weld bead is relatively soft and non-porous, making it easy to grind, file, or machine to a flush finish.
• High Strength: While it is technically a brazing process, the bond strength often exceeds the strength of the base metal in lap or tee joints.

Common Applications

• Automotive: Repairing thin sheet metal panels, exhaust systems, and cast-iron manifolds.
• General Fabrication: Building furniture, bicycle frames, and decorative wrought-iron work where a smooth, bronze-colored finish is desired.
• Maintenance & Repair: Patching galvanized water tanks, repairing cracked pump housings, and building up worn surfaces on brass or bronze components.
• Agricultural: Repairing implements and irrigation fittings where a high-strength, leak-proof seal is required.

Usage & Safety Tips

• Flux is Essential: This rod must be used with a brazing flux (such as Matweld Brazing Flux). Heat the end of the rod and dip it into the flux powder; the flux will stick to the rod and clean the metal surface as you braze.
• Flame Setting: Use a neutral or slightly oxidizing flame. An oxidizing flame helps to minimize the vaporization of zinc from the rod, further reducing fumes and porosity.
• Cleanliness: Even though the flux cleans the metal, heavy rust or grease should be removed with a wire brush or Herschell Clean Up Spray for the best capillary action.
• Galvanized Caution: When brazing galvanized steel, the zinc coating will vaporize. Ensure excellent ventilation or use a respirator designed for metal fumes.
• Cooling: Allow the joint to cool naturally. Quenching a brazed joint in water can make the bond brittle and lead to cracking.