Brass/Pure Copper Pure Bare Copper Wire Wire Bonsai Jewellery Craft Cu 0.2~0.5mm

A general rule is to select a wire diameter approximately one-third the thickness of the branch you are training. For young, flexible shoots (typically 3–6 mm thick), 1–2 mm wire is a common starting point. For thicker, more established branches, 2.5–5 mm wire provides the rigidity needed to hold the set position. Copper wire is preferred by many bonsai practitioners because it work-hardens slightly after bending, holding the branch more firmly than brass at the same diameter.

Brass is an alloy of copper and zinc, giving it a bright gold-yellow colour and slightly higher stiffness. It is well-suited for decorative wire work, jewellery components, and craft projects where a gold tone is desired. Pure copper is softer and more malleable, making it easier to bend repeatedly without cracking. It also develops a natural green-brown patina over time, which many artists and bonsai growers find desirable. Copper is also electrically conductive, making it suitable for grounding or simple craft electronics.

Neither brass nor copper will rust (rust is specific to iron-based metals). Copper will oxidise and develop a patina — ranging from dark brown to green — depending on exposure to air and moisture. This patina is stable and actually protects the underlying metal. Brass oxidises more slowly and retains its gold tone longer indoors. If you prefer to maintain a bright finish, a light coat of clear lacquer or jewellery sealant applied after forming will slow oxidation.

Pure copper wire is generally well-tolerated for most people in short-term skin contact, though some individuals may experience a temporary green tint on skin from copper oxidation — this is harmless. Brass contains zinc, which can cause reactions in people with zinc or nickel sensitivities. For sensitive skin or prolonged wear, pure copper is the safer choice, or consider applying a sealant to the finished piece. Neither material is considered hypoallergenic in the strict sense.

Yes. Both brass and copper wire are solderable using standard soft solder (tin-lead or lead-free) with an appropriate flux. Copper solders readily with silver solder as well, making it popular for jewellery fabrication. Brass can also be silver-soldered but requires slightly higher heat. Because the wire is bare and uncoated, no stripping or pre-treatment is needed before soldering — simply clean the surface with flux and apply heat.

For a single jewellery project or a small bonsai with a few branches, a 1 m or 5 m spool is typically sufficient. If you are training multiple trees through a growing season, or running a craft workshop, the 10 m, 25 m, or 50 m options offer a lower per-metre cost and reduce the need for frequent reordering. Larger diameter wires (3 mm and above) are used in shorter lengths per application, so a 5 m or 10 m spool often covers an entire bonsai season for one tree.

For fine diameters (0.2–1 mm), round-nose pliers, flat-nose pliers, and flush wire cutters are the standard toolkit for jewellery and wrapping work. For medium diameters (1.2–2.5 mm), bonsai wire cutters or heavy-duty flush cutters are recommended, along with concave branch cutters if you are working on trees. For the thicker gauges (3–5 mm), heavy-gauge wire cutters or bolt cutters may be needed, and a bench vise can help hold the wire while bending. Always wear eye protection when cutting wire under tension.