I've heard that the soldering temperatures aren't nearly enough to make the lead a gas and the fumes from the flux are what can kill you. I suppose the same advice applies in that case, but is that accurate?
Yes that’s accurate for hobbyist work. There will be some lead vapour, but at the temperatures used for soldering we’re talking a few atoms. The flux is much more of a risk, and both are mitigated with proper fume extraction.
Lead does bioaccumulate so continual exposure to low levels is dangerous, but unless you’re soldering all day every day it’s not likely to be dangerous.
If you’re a factory and have multiple wave soldering baths operating it’s a different story.
Lead has a boiling point of 1749 degrees C. That is at least 1200 degrees higher than your typical soldering temperature. If you use a propane torch you’ll almost touch that temp.
Correct, but all materials have a vapour pressure so there will be a very small amount of lead vapour when soldering. Based on lead’s vapour pressure it’s in the range of a few atoms, I haven’t done the math though.
I mentioned it for completeness because someone else would if I didn’t.
Quick math shows that vapor pressure of lead at 500 degrees C is 1/7,600,000 of an atmosphere. I don’t know how to calculate the rate of sublimation but this does seem pretty negligible.
Did you ever forgot a cup of water somewhere? It fumed away after 2 weeks! All without boiling it. :-O
Same applies to lead, especially if you heat it to 360 C.
Do you know how dangerous new vs old flux is? I'm using some old Канифоль from the USSR and get headaches while soldering. Fume extraction would probably be a good idea, but I solder no more than 4h a year
There is a technique where you breathe out as you solder. No idea if канифоль is toxic or not but honestly if it gives you headaches why not try another type? Or wear a respirator?
Most electronics fluxes aren't particularly toxic, but rosin is a sensitiser - repeated exposure will cause an increasingly severe allergic reaction. Working in a well-ventilated room is probably fine if you only solder occasionally, but anyone who is soldering regularly should be using a good fume extraction system.
