The first method is visual inspection. High-quality solder wire looks lustrous, shows no oxidation and will not turn black.
The second is to feel it by hand. High-quality solder wire does not rub off onto your hands easily when wiped. If your hands turn dark after handling it, that indicates a relatively high lead content. Solder wire is generally not too hard, which makes it convenient to feed during use. It has good ductility, so the softer it is, the better the purity. Experienced workers in the soldering industry can usually tell which solder wires are high quality and which have a high lead content just by handling them. Without some experience, however, the subtle differences between these solder wires are impossible to detect.

There are also many types of Solder wire available on the market, so when choosing high-quality solder wire it can sometimes be difficult to judge by appearance alone, and it is best to be cautious. Solder wire should also be judged on insulation resistance, expansion rate and moisture resistance. As for lead-free solder wire, check whether it complies with RoHS; the identification criteria include Flux residue, halogen-free content and tinning speed.

In short, to choose a good product it is essential to select the right manufacturer. Shenzhen JJY is a Solder Paste and wire manufacturer with a long history, specializing for more than 12 years in the R&D of solder paste, solder wire, lead-free solder paste, Leaded Solder Paste and Solder Bars. For solder paste, choose the JJY brand. Feel free to contact us!