I've been soldering for much of my life, dating back to the late 60s when I became an Amateur Radio operator. I'm 69 now, and starting to feel my age 🙂 During that time I've never used any fume extractors or any other special equipment when soldering, although nowadays I turn on a fan when I'm soldering to blow the flux fumes out of my face. And I don't eat when I'm soldering. Anyway, a couple of years ago I got to thinking about lead exposure (I have always used 60/40 solder) so I asked my Primary Care Physician to check my lead levels. The test came back at the bottom (almost undetectable), so I was relieved. Of course, that doesn't mean I haven't been exposed at a low level of lead all these years, and it's my understanding that lead doesn't leave the body very fast, especially in the case of bones and teeth. Spurred on by this video, even at this late stage in my life I'm now actually taking more precautions when soldering, and will be setting up a fume extractor soon.

63/37 is not your " basic 60/40 solder" That exact mix of 63/37 makes the solder eutectic meaning it does not have a melting range but a melting point and so consequently it also has a solidifying point in stead of a range. In other words, when the solder cools down it solidifies all in one in stead of being malleable (past like) for a while before becoming completly hard. That way it prevents a "cold joint" due to moving the joint while cooling down.

I'm almost 73 years old. I've been soldering with lead solder for 60 years. I'm also a gunsmith, licensed in the City of New York for many years. Needless to say, I have handled a lot of lead. My blood work has never had ANY concerns with lead levels of any kind.

As a child I remember a kid trying to convince me his walls tasted sweet. I remember this HUGE gap where he had (over aeons) ate the paint of the wall. He didn’t do well in school, but being a child I never made the connection. Many moons later and I’m an adult learning about the things you demonstrate here - someone mentioned kids get brain damage from lead paint because it tastes sweet. Horrible flash into the time fog! I’m glad we have learned lessons and paint like that is avoided now - but I totally agree about the precautions with older wires etc in particular!

I get tested about every two years. I'm on year 38 of soldering. A lot. So far I'm below detectable limits. Always wash hands afterwards! Don't eat or drink at the bench.

Contrary to common belief there is NO lead in leaded solder fumes, lead vaporizes at 1749 °C (3180 °F) , no soldering iron gets that hot, the only fumes are from the flux and generally the flux used for lead free solder is more harmful than the flux used for leaded solder I'm 52 have been soldering since my early teens and have never really taken any special precautions, my lead levels have been tested and are perfectly normal.

"The Poisoners' Handbook" is a fascinating history book about the development of forensic medicine and the search for scientific methods to determine the cause of poisonings, whether accidentally or purposeful.

For years I used a hot-type machine called a Ludlow that cast lines of type for making rubber stamps. I still have some jeans with lead splatters on them. I never thought about the lead at all, though back then it was still in the gasoline. Probably shaved a few points off my I.Q., but I wasn't gonna be a genius anyway! You, on the other hand, need to take care. Love your ideas and adventures.

Arsenic, which was once used to make dyes for wallpaper, also tastes sweet, and children would poison themselves by licking the wallpaper. Similar to kids eating sweet-tasting paint chips and getting lead poisoning. When we were were kids we used split-shot, small round BB-like lead weights with a slit in them that you could squeeze onto the fishing line; we were supposed to use pliers for this, but if we didn't have pliers, or the pliers had frozen solid with rust while sitting in the tackle box, we used our teeth! Nowadays, most fishing weights and lures aren't made with lead anymore.

Lead/tin solder is just soo much better, especially for hand assembly, or repair/rework. I also like the Hakko 951 as the station, it's got better temp regulation, and the includes the option for a switch stand, that turns the iron off when it's in the stand, reducing fumes and increasing tip life.

The old timers, who worked on the dew line, and i learned electronics from used drums of carbon tetrachloride to wash equipment in. They seemed to be mostly ok. :)

This vdieo should be one of those "required reading" videos. Thank you! Except for mercury I use basically every chemical you mentioned, and will be much more careful!

We had a barrel of Freon with a loose pump in the hole on top. This we would put into ~1 L bottles (and all over the floor). These were used to brush the Freon onto cards to remove flux. Always fun to send the newbies into the Freon room with a styrophone cup, which would dissolve instantly on contact with Freon. When asked how to dispose of contaminated Freon, my boss said, "Pour it on rocks out back. It will evaporate." I love to see people today always going for the PPE.

When I was young and stupid I used to light cigarettes right off the (tinned) tip of my Weller soldering gun. I'm now old and not quite as stupid, and no longer smoke. Luckily didn't poison myself, and wised up a good deal in the decades since.

Very informative! Thanks Fran. Cheers!

Really like this series of QAs! Nice rhythm, nice length. 😎

So true, thanks for the reminder.

Just to let you know that despite being subscribed with notifications on I haven't had a single notification for months. Don't you just love KZfaq.

Very well done! We appreciate all your experience and comments. Best Regards!

I used to work a lot with solder. Sometimes I used a fume extractor. I never ate around my workstation. For an unrelated health issue I had my lead level tested in my blood. It came back low normal.

For me, the biggest problem with solder is the solder dust and small chunks that build up in the soldering stand and brass tip cleaner. I was surprised you didn't address this...

Excelent topic Fran!

Thanks, Fran, nobody ever taught me soldering and while I've done it for years, I never have done it a lot. I didn't know about any of this!

The old time radio station chief engineers often smoked. I recall one defying gravity with a long line of ash, sticking to his cigarette, and the ash hovering over a wired chassis. Rest in peace Don Holmes 580 AM CJFX Antigonish, Nova Scotia. They were I believe the second station in North America to use a 10.000 Watt Nautel AM transmitter.

Lab 3.0 is coming along quite nicely!

When I studied chemistry ('72-7) we were wary of mercury vapour and benzene. However everyone had squeeze bottles of acetone. And so many exotic organic compounds... Some must have been deadly - still here I am😁

Yes! A pragmatic approach to hazardous substances is the best, especially when working with vintage gear where lead, asbestos and PCBs are unavoidable. Understand the risks, and develop a personal protocol.

One of my slack time tasks that I was given as a Technician was to decommission a large number of Mercury manometers. I was worried when I was told of the task but reassured when I found that the next task after that was going to be to decommission the 'Mercury Room' that I didn't realise that the works had. It was a bit grubby but it had a downdraft bench and all the PPE to keep me safe. Oh and the first part of the task saw me being sent off site to a chemical company to undergo Mercury handling training course. One hit training, trained for the one job then never used the training since.

Love the hat! I used lead solder for 20 years with no hood. Safety was not a real thing until the late 90's. I would just blow on the solder to keep the fumes out of my face. I often wonder if my old habits will cause some sort of long term illness. She is right, Use common sense. Solder in well ventilated room , wash your hands when done handlining lead solder, don't eat and solder. clean your work station when you are done, wipe things down if you have pets.

In the 80's Methylene Chloride was used in large amounts in circuit board manufacturing. Pretty much the entire plant had vats of it. They literally had it on tap so workers could fill their small pots with it and use it at their stations. I recall pretty elaborate health related paperwork in being hired, and supplemental to that too but wasn't around for too awful long. Long enough to have gotten MC on my fingers in small amounts regularly. You would use a cotton bud / q-tip dipped in MC to clear off any epoxy you had accidentally gotten on a pad while you were touching up where the silk screened epoxy was insufficient. It takes almost nothing but the slightest touch and MC will wick right into you. In the silk screening process if a worker screwed up an entire important board, they could walk over and dip it into the large open vat of MC. Come out clean as a whistle, that is for dang sure. When I think of it now, I shudder a bit.

Beryllium is another one to be aware of and Its probably the worst of them. (It causes berylliosis) Its was and still is common as HV insulator, and it was also used in old heatsink compounds. I.e. may be found in ceramic insulators, things like magnetrons. Id be cautious with old heatsink compound.

I was a leadman on a soldering/electronic assembly line and later a soldering instructor. Never heard of lead problems from soldering with tin/lead solders. Had a friend who was a welder and a welding instructor, developed brain cancer from welding fumes. That may be where tales of lead danger from soldering may have come from. Don't put solder in your mouth or eat while soldering, have a fan going for prolonged soldering work, (couldn't hurt). Unleaded solders and fluxes require higher heat and possible damage to plastic connector bodies and circuit boards, possible unreliable connections due to poor solder flow when used in hand soldering . Use 60/40 tin/lead rosin core solder for hand soldering and good technique in care and cleanliness of iron tips, "tinning" of wire ends, use of flux, quick heat transfer, watching solder flow, and practice. It's good to have a third hand, a helper, or holding devices.

During my time in the late 1970s as a radio maintenance tech in the USAF I took the NASA soldering course. They used Pace soldering stations and after a few hours the classroom was thick with fumes. Plus you cleaned boards and components with acetone and carbon tet.

P.S. All of those chemicals you mentioned, we had on the carriers that I was on and used on aircraft a lot. Not to mention all of the munitions we had to hand load.

Interesting to know. Thanks

It is nice to see many commenters concerned about lead poisoning from soldering. I always use a small fan to blow away fumes from soldering since I was a teen. You should actually be worried more about transdermal liquids that are mostly still sold as solvents. They can damage organs and nerve endings.

Never thought about acetone being transdermal. Some good stuff in this one. And a story. When I was very young, we used to play with asbestos sheeting. Throw it in a fire and what for it to go pop. I even have a purchased rock collection with a good size chunk of asbestos straight from the ground. And at school the used to use asbestos based paints in the classrooms. Stipple the ceiling so plenty of small bit. Still kicking to :)

The school chemistry lessons I had back in the '50s were interesting but would NEVER be allowed today!!

Fran ! Love your channel, love you. I so much respect and admire your fine mind which is a gigantic library just choc full of such a wide variety of "knowing" ~ what, how, when, why. You are a truth teller, a myth debunker, an extraordinary explainer of things, a do-er (not just a "talker"), a scientist, an engineer, a designer, a developer, an entrepreneur, . . . an all-around competent, capable gal. Your curiosity, wit and humor abound. Wish you my physics prof in college. I look forward to each of your videos and hope you continue posting for a loooooooong time. Thank you. (I played with liquid mercury too as a kid -- from a broken thermometer -- YIKES!)

Have you done a video on Tin Whiskers? Mercury vapor under UV light is also scary...

I continue to use lead solder for the reasons you mentioned, it works great. I actually like the smell of the flux, but then I'm not soldering all day. As you did I played with metallic mercury as a kid and dipped coins in it to make them shiny. Mercury switches were pretty common back then and I broke open a bunch and kept it in a small baby food jar. My understanding is that metallic mercury is not nearly as dangerous as vapor, so I guess I dogged a bullet growing up.

But then, the most toxicity at work usually comes from..the people, not materials.

SN100C! (The Nihon stuff, Allied manufactures it, though Kester has a "K100" that is not as good.) I like the "FastCore" flux when I get flux-core wire, but there's choices. Which brings me to flux: You're right to bring it up. Flux fumes BAD, idle iron is just an unhealthy chemical candle. I built my station lead-free from the start, which is kind of necessary, and have a separate station for taking apart vintage equipment. Btw, since you like your eutectic 63/37, SN100C is eutectic! One last PSA about benzene, etc. Wonderful advice about volatiles. Minimize exposure, or wear throw-away gear and a P95 or better mask. Minimizing exposure being the easier option. Also benzene et al turns up in weird places, like 99% isopropyl alcohol; it has no health utility whatsoever, btw (the 70% stuff from the pharmacy is optimal for healthcare), but the industrial sizes and mixtures use "drying agents", hence the MSDS sheet you get with it. It preserves the proportions of the solvent, but it's extremely toxic; don't touch without gloves. And great advice about military hardware; also applies to civilian firearms (sights) and _to hospital antiques_! It's too bad wide-spectrum detectors are so expensive, but they really are the price of admission for vintage gear. Got to have β, γ, and X-ray detection. Long post, but there's a lot of stuff that you wouldn't expect to be dangerous, especially if you didn't buy it new with its safety literature. End PSA. Thanks for the great vid Fran.

All of this reminds me of my dad's acquaintance of a guy that reloaded and manufactured all of his ammunition all throughout his life. It got to him and he died of some type of cancer specifically from that ammo process. He was a great marksman with many trophies. Both have long since gone now. No matter what it is, you have guidelines you must adhere to.

Thanks

The ventilation is good, also washing hands. Also opening the windows, but in my case the moment I open the window the gases from cars passing in front of my window give me a headache, so I open the windows from the other side of the building or I check the wind direction. Sometimes I leave the room for refreshing the air for a half of an hour because I like the air with good oxygenation.

Oh, the joys when the mercury fever thermometer broke! 😄 And the lead vapors from soldering. The smells of the CCl4 cleaning solution in my dad's print shop... No wonder I sometimes think I am on the autism spectrum... 🤔

I use Ersin Multicore most of the time. I have it down to 0.0a5 inch. The assembly workers at Microdyne were test for lead once a year, Some had been there for over 20 years and none ever had detectable lead.

Large companies typically have a 'medical' member of staff responsible for 'employees health' and their job is more legal than medical. Primarily to ensure the company has safeguards in place to prevent them being sued for industrial disease. They will 'health screen' employees by searching for risk and then 'interview' the employee, invite the employee to recognise risk, identify measures to reduce the risk and then take a signed statement from the employee that they will wear thick gloves, facemask, rubber boots, rubber apron, etc. That way if ever a industrial injury claim ever goes to court the company can supply the evidence that absuelves them from responsibilty.

Yes may of these things we know but sometimes we need to hear it.

You have to wonder about neural damage from various chemical exposure. I had a neighbor who worked for the USDA at the lab in Peoria, IL for 30+ years. He ended up with Alzheimers. He started work there in the 1950's prior to all the modern vent hoods and retired in the late 1980's. He worked with urea-formaldehide for some time creating corn based products for insulation and biodegradable plastics. AND he smoked unfiltered cigarettes for many years before he quit.

Also some organic solvents (e.g. acetone and methylene chloride) will penetrate through nitrile gloves, so other material gloves are sometimes required when using these.

7:17 used to play with mercury too, my grandfather had a vial of it taken from old pieces of equipment in his workshop. I used to take it into school and we would play with it in physics class, putting it in our palms and coating coins in it, was lots of fun. This wasn't like forever ago either, it was like 2002-2004 which admittedly does feel like "back in the day" now but still I think quite removed from the years when playing with mercury was a normal thing :D

Lead boils at over 700ﾟF but but tin/lead solder is formulated to melt at far below those temperature, and so virtually no lead is actually outgassed when you are soldering. Some people find ordinary rosin flux fumes to be quite irritating. I don't, and I have found no evidence of rosin fumes actually carrying lead or being a major health hazard, but ideally I guess you should avoid breathing it if you can by using an exhaust fan. Lead-free solder fluxes, however, contain organic acids, and that stuff is nasty and harsh to breathe. Unlike rosin flux, lead free fluxes are also conductive and corrosive, and must be thoroughly cleaned from the circuit board or it will cause problems down the road. Lead free solder also breaks down, and crystallizes and degrades at extremes of temperature (both hot and cold; Google the phenomenon known as "tin pest"), And the higher temperatures required for lead free solder, in conjunction with the corrosive acidic fluxes, will beat the heck out of the tips of your soldering iron in short order. I use only leaded solder. BTW, I made my own fishing weights and lures from molten lead as a boy and have come through unscathed. PS, Liquid Mercury actually sublimates and turns to a gas at room temperature and the vapors are more dangerous and more easily absorbed then the liquid metal is. Most of the environmental Mercury that builds up in the food chain and concentrates in larger predatory fishes actually originates from coal burning power plants. The exhaust is carried on prevailing winds to the coast and comes down with rain, where it is then acted upon by micro organisms and turned into Methyl Mercury which is highly neurotoxic and easily absorbed into fatty tissues.

I find this an interesting discussion. One of my favorite memories as a small child was of the smell of soldering coming from my father's Ham Shack. As a Ham he built many many Heathkit radios, audio amplifiers, and other project kits if his own design. He worked as an engineer from the 40s thru the early 80s, and taught himself radio growing up in the 1930s. Here I am , now in my mid 60's, having also worked as an engineer, so I will be curious to see any negative impacts from that early exposure.

Lead 60/40 is all I buy .Great video.

The problem with all those chemicals that cause slow neural damage is it can turn you into an Internet troll without your even realizing it.

my experience was, if you use bad lead free solder its a pain and you never touch it again. but we tried some with high silver at work and meanwhile i think its even better :)

Solder for me is always in a tube, so that you are not holding it in your hand direct. Lots of tubes I have used, even the ones that were sold for that, but most are old fizzy tablet containers that got repurposed. Solder off a roll using a drill and a philips screwdriver as mandrel to wind up a large roll, and then slip into the tube, pop the end through the small hole in the lid and use it. That way I minimise touching the solder, where oil off your fingers makes the outer surface dull and corroded, so no touch means longer life and better use of the flux. The sweet taste of lead is mostly from the organic acid products of lead being used, like lead acetate, used a lot to make sweet wine by the Romans, and then lead oxide, used to make white paint and as a white base in old lead paints. Both sweet, especially the lead oxide after it reacted with the linseed oil that was used to make the old paints, forming organic lead compounds that are water soluble. Mercury is not terribly toxic as a pure metal, it is when it reacts with weak organic acids and becomes the ion that is the problem, and just skin contact alone will not be immediately fatal. Prolonged, as in years, exposure to mercury vapour, say from being a Zama Zama illegal gold miner, will kill you, as the vapour condenses in the lungs, and reacts with the body there, slowly killing you. Organic solvents unfortunately are really good as solvents, and when they dissolve DNA then you get problems.

Used to work in natural gas measurement. Some of the very old meters used mercury. We had to drain out the mercury, squeeze it thru a rag (by hand) and put it back into the meter, adding some to make up for any losses. My hands were silver colored after that and used kerosene to wash it off best as possible, followed by water. Still have about a pound of mercury stored in a cupboard. LoL .. Not aware of the dangers back then.

Worked around TCE a lot years ago.

hearing about the precautions you take, i'm all the more convinced I'll be sticking with lead-free. no way I could keep up with that.

Lead Solder is the best!

What is the name of the crank holodex at the video intro ? that will be a fun project to make with kids.

We soldered with lead in school, and we were taught the fumes were bad to breathe in, but nothing really about washing our hands and such. While we had fume extractors the first year, we didn't the second year. I remember we used to have a lot of fun with melting big blobs of solder and push it over the edge so it would make a splat on the floor. Not at all what one should do, but our teachers didn't seem to care. I haven't soldered much since, but I have a small spool for the few occasions. I never tried non-lead solder, but I think it's long overdue to stop using lead solder also for hobbyists. It's just a really bad thing to get in your body, and you can't get rid of it once you do. Silver and copper is poisonous too, but it doesn't stick around.

What type of Geiger counter is suitable? Could you show us what you use please?

Its not just about the user its about the places and people where it comes from. Like Pitcher Oklahoma which is now uninhabitable

a quick check to msds is a must before using any substance

Most of us of "a certain age" used carbon tetrachloride for contact cleaner. I was practically up to my armpits in the stuff for years....and as anyone can tell you, I'm perfectly normal!

I saw Mercury, Lead & Asbestos at The Forum in '79. Or so my friends tell me.

Back in the day, I used naphtha to clean parts, and that stuff used to make my hands hurt.

I like to think of ingesting small amounts of toxic stuff as entering a shit lottery. some people do it for years and see no negative side effects, while others aren't so lucky.

I've known a number of older Techs..only one died a bit early, but he was chain smoking and possibly eating at his bench, and worked very long hours kinda thing. The rest seemed to do well, though after listening, it brought back a memory of how my mentor (past Military service, in electronics) seemed to radically change, like mood swings, fast temper, as his age increased. Was it old age, or lead, carbon Tet etc exposure.

I misread the title and thought this video was going to be about co-workers making fun of people who like to paint lead soldiers. This was very interesting and a bit scary; all the precautions needed to safely do a lot of soldering.

I use 60/40 and don't really care about poisoning since I don't put it in my mouth :) Have worked as a typecaster, dealing with an alloy of lead, tin and antimony, most of it being the lead. Not worrying about the vapours too much though, as the metal is close to its melting point and the intermolecular bonds will keep it from evaporating. Haven't even smelled it. The real deal is volatile organic components from decomposing machine oil on typecasting machines, or flux from the iron tip. That stuff can be cancerous if you inhale too much of it. Smelled enough acetone, isopropyl alcohol, ammonia, toluene, cyclohexane etc. through my studies in chemical engineering. And I think I'm still rather smart, LOL. Asbestos... yes, I remember your commentary on all these girls working in the vacuum tube manufacturing industry. As long as it doesn't strip off forming fibres, it's relatively safe. I wonder if asbestos could be kept together with some spray paint that forms a rather thick and flexible layer, and penetrates the pores in the stuff. "Mercury, lead, asbestos" is good, but "salt, asbestos, curtain" is certainly better :)

What should we be doing with all the old used solder wick and extracted lead solder removed by a solder sucker, or vacuum powered solder remover? Putting it in the wastepaper basket can't be proper.

I believe that, back in the day, research chemists used to taste the new chemicals they created.

I'm pretty sure the flux fumes are a way larger hazard than the lead in solder. I remember doing some big soldering projects with rather inadequate ventilation, and feeling pretty weird the days after.

Back in my day.......... Everyone in the office smoked, except me. There was always a blue haze throughout the building. It's a wonder that I don't have cancer... yet.

I can't even buy leaded solder for home use from my electronics supplier here in the UK, Rapid Electronics, so I went over to lead free solder. 99.5% tin, 0.5% copper and a trace of cobalt. Granted, it feels different to work with after 35+ years of using 60/40, but after adjusting my soldering station to find that sweet spot over the first few days of using it, I don't notice much of a difference to the leaded solder I use at work now TBH.

Bit off topic Fran but how is your sense of smell/taste now after Covid?

I'm only a hobbyist, and don't really do all that much soldering. But this is definitely food for thought, and even as a casual user it seems like some PPE is cheap insurance.

I'm just a hobbyist. Depends on the project, but generally I prefer not to use leaded solder anymore unless I'm working on a device where I suspect lead was used in the first place. I am acutely aware that it's dangerous and it just takes the fun out of it all. What does worry me is inhaling rosin flux and isopropyl alcohol... I generally solder outside but I think you still get plenty of those fumes...

I've used lead solder since I was a kid building projects! My dad was careful about teaching me safety - he was a plumber and regularly used lead to seal sewer pipes. He died just short of 90. Diabetes got him, not lead!

Your 63/37 is eutectic and does not do cold joints compared to 60/40. I must say I have NEVER heard of anyone poisoning themselves with solder in electronics including people who always held solder in the mouth like Steve Wozniak, or worked at a PCB plant with solder wave equipment, and we never used fans or anything like that. And this is elemental lead. It is not soluble in water or fats. I hear of it from lead smelting but not lead mining. Same for mercury. You need a compound that is soluble. But I am probably out of date. I am much more concerned about solvents - and old paint with lead compounds, red or white. Nonetheless, thanks for the video.

Old Linotype machines used an alloy of lead, antimony, and tin to make the hot metal slugs comprising a line of text for printing presses. Imagine working inches from a molten container of it for years at a time.

I poisoned myself so much with lead when I was younger. From working with lead welding it whilst smoking and eating. Then when I got home i used to solder with no fumigation. I'm surprised I don't piss bullets

A real bad mix, is having exposure to lead, and at the same time having plenty of amalgam tooth fillings. This produces the combo of lead and mercury messing with your bodily functions, with the autoimmune system being hit the hardest.

At least in Germany solder wire containing lead is (officially) no more available. However the substitute is not by any means working as good as as the "Fluitin" (American product?) LSN60. Therefore I try to obtain a LSN60 solder from China quite successfully. But in this solder the flux isn't so good. The new solder has a wide temperature range with a "creamy" or half-solid consistency, which makes it difficult to produce solder connections with a nice, smooth and shiny surface. Besides this I have been using this LSN60 solder for more than 50 years and "survived" this with obviously no damage.

You have some signal interference on your audio track. Please investigate if possible. Thanks Fran!

I've always used 60/40 solder. I never have had a problem over the decades of electronics work. I a) never put anything in my mouth when soldering; b) always wash my hands, twice, when done. I've never used any air filters/gloves or eye protection. I'm still alive and have never had any symptoms of lead poisoning.

I ran an electronics manufacturing facility doing mostly hand soldered circuits and circuit boards. I hired a workplace safety company to come in and attach air sampling containers to capture the same air the employees were breathing when working. They attached to their neck and pulled in the air for 8 hours a day for 30 days. No measureable

After touching PbSn solder, its prudent to wash your hands prior to going to the toilet particular for #1s. Apparently there are recorded cases of testicular cancer from this cause. And of course wash your hands after using the toilet as well.

Fran you are very intelligent and thanks for sharing information to us!

Another consideration with unleaded solder / components: I've read that soldering lead-free components with leaded solder is fine, however, soldering components "tinned" with leaded solder (e.g. "vintage" components) basically requires that you use leaded solder, otherwise tin dendrite growth can occur, which could cause a short. IIRC, it has to do with the amount of lead in the joint - in the former case, there's an overwhelming amount of lead in the joint, whereas in the latter, there's a small percentage of the joint's mass that's lead, which apparently allows dendrite growth. So, you have a good reason to be using lead solder with vintage components.

I worked with an engineer that would hold solder in his mouth. He was a biomedical PhD and his wife an MD. His lead levels were normal as he was tested often. He was about 60 at the time.

I have an uncle with serious neurological issues, probably from long term exposure to solvents.

Everything is hazardous if you manage it wrongly enough. But that's why they're the trolls. That said, thanks for the tip about the iron filter -- I'll have to pay closer attention to where that smoke goes next time.

I had no idea lead free solder had such problems. I've only ever used leaded because i had some free rolls that came with electronics. I guess the problems we've been having at work from solder joints breaking (besides the ridiculous heat stresses in this particular light) could be caused by lead free solder.

Lead in it's metallic form isn't very dangerous, you could eat a piece without much exposure...but in it's salt form, lead sulphate, lead oxide, etc it is very dangerous. I've been using lead solder for over 40 yrs, holding it in my mouth at times, also used to hold pellets for my pellet gun when I was a teen in my mouth...