Solder Wire Onnline 250 g SN97CU3 3.0 mm - Onnline

Flux-cored solder wire Onnline SN97CU3 is a lead-free alloy composed of 97% tin and 3% copper offered on a 250 g spool with a 3.0 mm diameter. It is formulated for general electronic and electrical soldering tasks that require a soft, corrosion-resistant joint with reduced risk of lead contamination. The wire's flux core supports wetting on copper and other compatible metals, making it suitable for hand soldering and repair operations in consumer electronics, electrical assemblies, and simple metal joining.

Advantages

The SN97CU3 composition provides good electrical conductivity and improved mechanical strength compared with pure tin, while remaining lead-free. The flux-cored construction simplifies application by supplying flux exactly where needed, reducing oxidation and improving solder flow. The 3.0 mm diameter is appropriate for medium-to-large joints and general repair tasks, and the 250 g spool size offers a balance between working volume and storage convenience.

Suitable for

• Hand soldering of electronic components and wires
• Repair and maintenance of consumer electronics and electrical connections
• Joining copper parts and compatible metals in workshops and hobby projects
• Tasks requiring a lead-free solder alloy with moderate melting and good wetting

Key specifications

• Alloy composition: 97% tin, 3% copper
• Flux type: flux-cored (activated for soldering use)
• Wire diameter: 3.0 mm
• Spool weight: 250 g
• Designed application: general electronic and electrical soldering, hand soldering, repair work

How to use

Prepare the surfaces by cleaning off oxidation, grease and dirt to ensure proper wetting. Heat the joint with an appropriate soldering iron or torch until the base metals reach soldering temperature, then apply the flux-cored solder wire to the heated area, allowing the alloy to flow and form a fillet. Avoid overheating to preserve flux activity and prevent damage to components. After soldering, clean any residual flux if required by the application or to meet cleanliness standards.

Usage recommendations

Use a soldering iron or heat source compatible with a 3.0 mm wire and select proper tip size and temperature for the metals being joined. For electronic assemblies, use controlled heating and clean flux residues when necessary. Store the spool in a dry environment to maintain flux effectiveness and prevent corrosion of the wire.