The flux in unleaded solder is far more toxic than the trace amounts of lead that one gets on one's fingers when handling leaded solder. Further, you can wash the lead off of your hands, whereas you can't wash your lungs out.
eutectic (read: leaded) soldering alloys are significantly easier to work with because they melt at a much lower (read: safer) temperature, and are less likely to yield "cold joints" when cooled. "eutectic" means "behaves like a homogeneous substance", in that eutectic alloys have a single phase transition temperature in which the alloy goes from solid to liquid and back.
"cold" joints are caused by micro-fractures that develop as an alloy in liquid state is cooling. non-eutectic alloys have intra-alloy bulk sections that solidify before other sections of the mass, and very slight movement can cause these bits that are cooling out of phase to solidify in such a way as to leave large voids in the joint. These voids do not conduct electricity as well as a voidless mass of bulk material.
You may remember the famous "red ring of death" from the first generation of xbox 360s. cold joints that formed over long periods of heating and cooling cycles on bga balls was the root cause of that issue.
HOWEVER, to get out of the weeds and science and so on for a second...
Look, when I was 15, I saw some circuits that I wanted to build. Some may remember Chu Moy, Kevin Gilmore, Tangent, Morsel, Phil LaRocco, Nelson Pass... They were my idols at the time, and they were designing these amazing little circuits that I, yes I! could put together and use if I could just figure out how to melt and solidify metal without destroying anything.
So, I went to Radio Shack, bought an iron in blister pack off the wall (forget desoldering -- I had no idea what was going on with that, I figured I just better not make a mistake...), some multi-core rosin solder about as thick as my wrist and went for it.
I built a few things, broke a lot more things, burnt myself _a lot_, and generally had a merry good time. I wore the tip on that radio shack iron down to a nub, starting experimenting with different soldering and flux alloys, different tools for removing solder, and the rest was history, or some such.
Hence, I am not saying that one has to buy this kit or spend 135$ all in one go or one will never learn to solder. I was there. I've tried every single one of the suggestions in this discussion thread and burnt off several fingerprints playing with them (no joke!), and yet I learned how to solder!
What happened is that I looked back on my own experiences, and knowing what I know now, using the resources that are at my disposal now, I posed the question: "What kit would I have given myself?":
with a goal of burning fewer fingers (and hands, and arms, and tables..).
with a goal of being able to reach for the same comfortable tools 15 years later.
This is the kit that I came up with. This is the kit that I would have given myself when I was 15. That's pretty much it.
eutectic (read: leaded) soldering alloys are significantly easier to work with because they melt at a much lower (read: safer) temperature, and are less likely to yield "cold joints" when cooled. "eutectic" means "behaves like a homogeneous substance", in that eutectic alloys have a single phase transition temperature in which the alloy goes from solid to liquid and back.
"cold" joints are caused by micro-fractures that develop as an alloy in liquid state is cooling. non-eutectic alloys have intra-alloy bulk sections that solidify before other sections of the mass, and very slight movement can cause these bits that are cooling out of phase to solidify in such a way as to leave large voids in the joint. These voids do not conduct electricity as well as a voidless mass of bulk material.
You may remember the famous "red ring of death" from the first generation of xbox 360s. cold joints that formed over long periods of heating and cooling cycles on bga balls was the root cause of that issue.
HOWEVER, to get out of the weeds and science and so on for a second...
Look, when I was 15, I saw some circuits that I wanted to build. Some may remember Chu Moy, Kevin Gilmore, Tangent, Morsel, Phil LaRocco, Nelson Pass... They were my idols at the time, and they were designing these amazing little circuits that I, yes I! could put together and use if I could just figure out how to melt and solidify metal without destroying anything.
So, I went to Radio Shack, bought an iron in blister pack off the wall (forget desoldering -- I had no idea what was going on with that, I figured I just better not make a mistake...), some multi-core rosin solder about as thick as my wrist and went for it.
I built a few things, broke a lot more things, burnt myself _a lot_, and generally had a merry good time. I wore the tip on that radio shack iron down to a nub, starting experimenting with different soldering and flux alloys, different tools for removing solder, and the rest was history, or some such.
Hence, I am not saying that one has to buy this kit or spend 135$ all in one go or one will never learn to solder. I was there. I've tried every single one of the suggestions in this discussion thread and burnt off several fingerprints playing with them (no joke!), and yet I learned how to solder!
What happened is that I looked back on my own experiences, and knowing what I know now, using the resources that are at my disposal now, I posed the question: "What kit would I have given myself?": with a goal of burning fewer fingers (and hands, and arms, and tables..). with a goal of being able to reach for the same comfortable tools 15 years later.
This is the kit that I came up with. This is the kit that I would have given myself when I was 15. That's pretty much it.