I bought a spool of it, and I haven't yet been able to make a decent solder joint with it. Liquid flux seems to help, but lead-free solder just doesn't want to "flow".
Back when microcomputers (6800, 8080, 6502) were popular, a friend of mine got a 6800 kit from his employer. It was part of one of the classes his employer was offering. He took it home and assembled/soldered everything together. But he didn't like that yucky look when you used solder with flux. So he soldered everything with flux free solder. When he was done, the computer didn't do anything, so he brought it over for me to look at. The whole computer board looked like one huge cold solder joint. It was probably the worst solder job I have ever seen. So I went about re-soldering the entire board with some good Kester solder, with flux. When I was done, the computer came to life and worked as it was suppose to.
This is the same guy that told me he found hidden memory space in that same microcomputer. He didn't understand how the memory addressing wrapped around in those small computers, and your were always addressing the same memory. It took a while to explain it.
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When I was a teen (late 60's) and still in high school, I use to earn some extra cash working for a guy that made bullets. I would sit for hours over a pot of molten lead banging out 38 slugs, 6 to 8 at a time. He made ammunition for the local police, so he ran through a lot of lead.
In his backyard, he had 5 or 6 propane melting pots. His lead source was any used commercial product that contained lead. Remember when toothpaste came in lead tubes? There was piles of old toothpaste tubes next to the melting pots. Any residual toothpaste just boiled off.
At the time, the lead was not the danger. The real danger was with the casks of gun power sitting on the shelves and the fact that we were working in his basement. And none of those casks had a warning label. If anything ever happened, the whole house would have come down on us.