[sitharus]

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.

[IgorPartola]

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.

[sitharus]

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.

[IgorPartola]

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.

[Aldipower]

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.

[IgorPartola]

I mean you can do an experiment: put a gram of lead onto a hotplate at 360C, then weigh it after 2 weeks. I would really love to see your results.

[hooli_gan]

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

[sitharus]

It really depends on the flux, even modern fluxes have a range of toxicity. The only way to know is to check the MSDS.

I use Канифоль/rosin flux as well and use a fume extractor. Rosin flux is the most common for flux-cored solder in my experience.

But a few times a year is unlikely to be an issue, soldering health effects are in people who do it for work.

[IgorPartola]

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?

[hooli_gan]

The answer is laziness