Have you tried Lead Free Solder that is now available? Does it flow as easily as lead based solder? Does it melt at about the same temperature? I’m more interested in the rosin core solder for electrical connections but if you have opinions about lead free solder for mechanical connections, I’d like to hear about that too.
The only thing it is good for is copper pipes. Use 60/40 rosin core. Kids used to bring this to my slot car track and it made for poor soldering due to there was no flux in the solder. You had to use a paste flux which was messy. Seems to flow better with a torch than a soldering iron.