Solder comes in several different blends, also known as alloys. 60/40 solder, which contains 60% tin and 40% lead, is the most commonly used. The newer 63/37 alloy is hands-down superior for the type of soldering we’re doing, and that’s all you’ll find on this page.
All of the solder on this page is also rosin-core. This means it contains a tiny bit of flux in its center so that you don’t have to apply any flux separately to the joint. You can just tin the pad or wire and know that the joint already contains the right amount of flux.
You’ll also notice that all of the solder on this page is leaded. Lead-free solder is harder to work with and produces worse results than leaded.
Is leaded solder bad for you? NO. Soldering temperatures are far, far too cold to vaporize lead. The fumes you see when soldering is the flux burning off (don’t breathe that). The main risk of lead exposure from soldering is lead particles on your hands. You can mitigate this simply by washing your hands after soldering. And don’t lick the solder.