A low-tin, high-lead solder alloy made of 10% tin (Sn) and 70% lead (Pb), with the remaining 20% typically other elements kept minimal (often trace antimony or none at all depending on source). This alloy behaves closer to a soft, high-lead solder and is mainly used where high-temperature tolerance and durability matter more than flow quality.
Where it’s used:
- Radiator and heat-exchanger work
- Heavy sheet-metal soldering
- Industrial joints exposed to higher temperatures
- Applications that don’t require smooth electronic-grade flow
- Legacy equipment repairs