Even as temperatures approach absolute zero, this indium solder remains soft and malleable, allowing it to form an airtight seal between metal and certain non-metal materials. It’s often used in cryogenic applications, including those with liquid nitrogen. This solder has a lower melting point than most solders, so it’s good for sensitive assemblies, such as semiconductors and electronic components. Unlike commonly used tin-based solders, this solder won’t damage gold plating on circuit boards. It’s also a good conductor of heat and electricity. More durable than standard tin-lead solder, this solder is less likely to crack from repeated temperature swings. It’s low outgassing, so it’s good for use in high-vacuum applications.

This indium-based solder can be cold welded, meaning it will bond to itself without heat. You can also use it for step soldering with traditional solders. It does not have a flux core; choose soldering flux to prepare workpieces for this solder.

This bismuth-tin solder has similar performance properties to lead solder, but is also safe for use in food-processing equipment and copper water pipes. It has a lower melting point than most solders, so it’s good for sensitive assemblies, such as semiconductors and electronic components, as well as for step soldering with traditional solders. However, it’s less thermally conductive than other metals and more brittle than lead. Flux isn’t required, but for easier cleanup use it with no-clean soldering flux. Do not use this solder on drinking water pipes.