Pure Copper Round Solid Bare Wire 3mm 3.5mm 4mm 4.5mm 5mm Craft DIY

For most residential grounding and bonding runs, 4 mm (~AWG 6 equivalent) or 5 mm (~AWG 4 equivalent) solid bare copper wire is commonly specified. Always consult your local electrical code (e.g., NEC in the US) and a licensed electrician to confirm the minimum conductor size for your specific circuit and fault-current rating before purchasing.

Both are the same 3 mm diameter solid copper wire. The soft-temper version has been annealed (heat-treated) after drawing, which relieves internal stress and makes the wire significantly more pliable. It bends smoothly by hand with round-nose pliers — ideal for jewelry wire-wrapping, fine sculpture armature, and intricate craft shapes. The standard 3 mm retains more spring-back and is better suited for applications where rigidity matters, such as structural supports or grounding clips.

Bare copper naturally develops a protective oxide layer that slows further corrosion, making it widely used in outdoor grounding electrodes and garden art. However, direct-burial suitability for electrical conductors depends on local code requirements — many jurisdictions require a minimum burial depth and may mandate a protective conduit or a listed direct-burial rated conductor. For purely decorative outdoor use (garden sculpture, trellises, floral wire), bare copper performs well in most climates.

Yes. Because the wire is uncoated, there is no insulation to strip before soldering. Use a rosin-core or acid-core solder appropriate for copper, and apply flux if needed for a clean joint. For brazing (higher-temperature joining), standard copper-compatible brazing rods and flux work without additional surface preparation. Lightly sanding the joint area with fine-grit paper improves adhesion if the surface has developed a heavy patina.

For clean cuts, use heavy-duty wire cutters or bolt croppers rated for the wire gauge — standard electrician's diagonal cutters handle up to about 4 mm; for 4.5 mm and 5 mm, bolt croppers or an angle grinder with a cutting disc give a cleaner result. For bending, a conduit bender, bench vise, or pipe bender jig prevents kinking. Gentle curves can be formed around a round mandrel (pipe or dowel) of the desired radius.

All bare copper tarnishes over time as it reacts with oxygen and moisture, shifting from bright orange to brown and eventually a green patina (verdigris). To slow tarnishing on decorative pieces, apply a clear lacquer or wax coat after cleaning. To restore brightness, soak briefly in a solution of white vinegar and salt, then rinse and dry thoroughly. For electrical grounding applications, tarnish does not significantly affect conductivity and is generally left untreated.

Measure the total run of your project and add 10–15% for bends, connections, and waste. The 1 m option suits small jewelry pieces or prototyping. The 3 m and 5 m lengths cover most single-circuit grounding runs or medium craft projects. The 10 m and 15 m coils are cost-effective for larger installations, full garden art structures, or bulk jewelry production where consistent wire from a single draw is important for uniform workability.