Rosin-cored solder wire in the sizes that actually get used. 2% flux content, 190°C melting point. Choosing a diameter 0.5–0.6mm — surface mount, fine pitch, ESP32 module pads 0.8mm — the general-purpose choice. If you're buying one, buy this. 1.0–1.2mm — through-hole, terminal blocks, connectors 1.5–2.0mm — heavy cable, battery terminals, high-current lugs Notes Thinner is not better. Using 0.5mm on a battery lug means feeding wire for a minute while everything around it cooks. Rosin core means no separate flux for most work, but a flux pen still helps on anything oxidised. Ventilate. Rosin fumes are an irritant. Delivery & import charges UK — free delivery. Price includes UK VAT at 20%. EU & international — free delivery. Your country's import VAT and any duty are not included and may be collected by the carrier before delivery. Please check your local thresholds before ordering. Dispatched direct from our supplier. Typical delivery 10–20 working days. SynkHaus is a smart home and solar installer. We sell the parts we fit ourselves.
