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I was reading about tin alloys for electronics soldering and found it it has about 40% of lead in composition. Lead, everyone knows, it's very dangerous to breathe due to being a heavy metal. Also, I found some recommendations using the combination of an exhauster and a respirator when working with soldering. Is there any international regularization of which respirator type should I use? If not, which type do you recommend? Beyond this, is there any additional safety equipment recommended?

For economics reasons and for better soldering resistance, I've already discarded Pb free solder reflow.

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    \$\begingroup\$ Is this for professional use (where you should get professional consultance that know the codes involved for your situation) or for hobbyist use? In the later case when you wash your hands after work, the more important problem is flux fumes. \$\endgroup\$
    – PlasmaHH
    Mar 23, 2015 at 12:29
  • \$\begingroup\$ You should be a bit more careful when working with lead solder paste as compared to wire solder. Wash your hands carefully after handling it, and preferably don't allow those who are (or might be) pregnant to touch the paste. \$\endgroup\$
    – Spehro Pefhany
    Mar 23, 2015 at 14:04
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    \$\begingroup\$ You'll find a reasonably comprehensive SE answer here: electronics.stackexchange.com/questions/19077/… \$\endgroup\$
    – Russell McMahon ♦
    Mar 23, 2015 at 14:07
  • \$\begingroup\$ Thx very much @RussellMcMahon! I've really searched on SE for related questions, but didn't found it. You've made it very clear for me. Thx again \$\endgroup\$
    – Pedro Quadros
    Mar 23, 2015 at 14:32
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    \$\begingroup\$ Safety recommendation: Do not pick up soldering iron by the hot end. \$\endgroup\$
    – Mark Adler
    Mar 24, 2015 at 5:35

4 Answers 4

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The dangers of breathing soldering vapor has nothing to do with lead content of the solder. The vapor pressure of lead is so low at soldering temperatures that there just aren't that many lead molecules in the air.

The hazards of breathing soldering vapors is due to the flux getting vaporized, and sometimes parts of components emitting gasses when they get too hot. Lead solder is actually a little safer in that regard since soldering temperatures are lower. However, the biggest variable is the composition of the flux.

If you are worried about this, get something called a fume extractor. This is a little box with a fan and a filter. You place it right next to where you are soldering. It pulls the vapor from soldering away from you and thru its filter. By the time the vaporized stuff gets to the filter, it's no longer vaporized but a bunch of small particles. The filter removes these particles from the stream before exhausting it out the back.

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    \$\begingroup\$ Thx for the explanation. Just the fume extractor, without a proper safety mask, will be alright? \$\endgroup\$
    – Pedro Quadros
    Mar 23, 2015 at 13:21
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    \$\begingroup\$ @Pedro: You are over-thinking this. Relax. Chill out. A safety mask is for protection against other things. In some very rare cases, soldering can cause splatter, which a mask prevent from getting into your eyes. Keep in mind that the vast majority of people soldering occasionally on their desk or workbench use neither a fume extractor nor a face shield. \$\endgroup\$
    – Olin Lathrop
    Mar 23, 2015 at 13:29
  • \$\begingroup\$ @OlinLathrop: Until recently it was the same for me, but after actually getting a tiny bit of solder into my eyes, I am often wearing my tactical glasses. If I hadn't have them around I would probably not use anything still, so it all depends on peoples level of paranoia. \$\endgroup\$
    – PlasmaHH
    Mar 23, 2015 at 22:30
  • \$\begingroup\$ @Plasm: How did you manage to get solder in your eye? I'm having a hard time imagining a scenario. \$\endgroup\$
    – Olin Lathrop
    Mar 23, 2015 at 22:56
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    \$\begingroup\$ @PlasmaHH: The only people I know who solder with eye protection are people who have gotten solder in their eye. Which probably doesn't prove much except that humans are much worse at assessing risk than we like to think. \$\endgroup\$
    – Matt B
    Mar 25, 2015 at 5:45
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If you want to sell your products in any civilised country you will be using lead free solder.

Creating lead vapour that you can breathe in with a soldering iron is impossible. It has a boiling point of 1749°C, and the melting point is only just below what you are soldering at. If you compare that to water, your solder is a block of ice, and when you are soldering you're melting the ice to tap water (or colder) temperature. You have to put the water in a kettle and heat it up to about 50% of its boiling point (50°C) to get it to start steaming. For lead that'd be around 850°C.

The fumes you see rising off the solder are not metal vapours, they are the fumes from the flux. Most common flux is contained in Rosin, a natural plant product, and it is the vaporisation of that which you see while soldering.

If you really must use leaded solder the main possibility of lead poisoning is through physical contact with the solder (getting lead on your hands) and then eating without washing your hands, thus transferring the lead to your food and then to your stomach.

Incidentally, countries that have banned the use of lead in solder have done so not because of safety or health reasons, but purely because of reclamation and recycling reasons.

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  • \$\begingroup\$ So, is there any need for using gloves? \$\endgroup\$
    – Pedro Quadros
    Mar 23, 2015 at 13:23
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    \$\begingroup\$ Only if you're soldering in a furnace. No, no need for gloves. Gloves will only impede your manual dexterity. If solder were that dangerous there wouldn't be anyone around to teach you to solder. \$\endgroup\$
    – Majenko
    Mar 23, 2015 at 13:50
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    \$\begingroup\$ Indeed. Solder is obviously perfectly harmless. People like eg Olin and I have used it for decades without any attention to protection. If you want good examples of how dangerous it really is just look at us. Then again .... :-) \$\endgroup\$
    – Russell McMahon ♦
    Mar 23, 2015 at 14:09
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    \$\begingroup\$ @RussellMcMahon: read through olins posts and then reevaluate any dangers... well, just kidding ;) \$\endgroup\$
    – PlasmaHH
    Mar 23, 2015 at 22:31
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    \$\begingroup\$ There is an unfortunate tendency for every activity to become safety concerned out of existence. I used to solder in bare feet, but stopped after the second time that too much solder on a tinned lead dripped and splashed on my foot. It actually didn't even leave a mark, but peeling a splat of lead off my foot did eventually leave an impression. I got more skilled and wore shoes. Lead is malleable, easy to handle, and really a lot safer unless you plan to lick it. So wash your hands, and don't stick solder in your mouth. You'll be fine. \$\endgroup\$
    – RBerteig
    Mar 24, 2015 at 0:48
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As long as you're in a well ventilated area, you shouldn't really care about what particles are floating around. If the ventilation is terrible, a table-top ventilator will improve the dissipation of particles resulting from soldering quite a lot.

It's a different story of-course when you put a bunch of soldering irons in the same room and use all of them frantically. For example, a class of inexperienced students who have their first soldering lesson. That's the moment you should worry about air quality and have a large air filter in place.

As @RBarteig stated, just don't stick it in your mouth.

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The only problems I've had are minor burns, usually from holding a piece long enough for the solder to cool when I haven't had a proper vise set up.

Or one time, a not-so-minor burn when soldering a water pipe, when a blob of molten solder landed on my hand but I considered the pain less annoying than the prospect of having to re-do the entire joint if I moved my hand away and let the pieces come apart.

I've also, I think, had minor skin punctures from DIP IC leads which can be quite sharp.

I've not heard of any diseases endemic to long-time electronics technicians - nothing like phossy jaw or miner's lung or whitefinger.

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    \$\begingroup\$ Prolonged exposure to flux gases have been linked to aggravated asthma. Might not be a fatal condition but long time workers in the electronics industry can find themselves unable to work anymore (with flux) because they develop hypersensitive allergies to the gases and can't breathe. For a hobbyist it's not worth worrying over, but it is important for people that solder for a living to take some precautions. \$\endgroup\$
    – I. Wolfe
    Mar 24, 2015 at 4:43
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    \$\begingroup\$ The main problem I've had is damage to clothing. I have a number of (silk) neckties with small holes from rosin splashes. The rosin doesn't seem to damage cotton shirts, though. (You can tell I go way back, since I used to wear a neck tie to work.) \$\endgroup\$
    – user128351
    May 19, 2017 at 18:01

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