Am I creating an unhealthy environment?
June 29, 2018 2:16 PM   Subscribe

I mean that literally, not figuratively. Is my recent electronics obsession making my apartment unhealthy for me, my girlfriend, and my cat?

I've been doing some repair work on electronics for the past few months. My workshop is my apartment. I posted this question about the smell of capacitors, which is probably due to phenolic compounds in the pre-1973 capacitors I was replacing. A few people said "limit exposure," which makes sense. I wanted to ask more directly about the general safety of my apartment, especially for my cat, who is much smaller and (presumably) more susceptible to environmental hazards than people are.

There's the general issue of lead exposure. Is the cat walking on the floor and ingesting lead residue from her paws? I do wash my hands diligently after soldering, but I don't know what the risk is like from splattered solder, the occasional cut wire that I may have dropped, and so on. She doesn't walk on my work surface. There's also the issue of solder and rosin smoke. I've read that solder smoke dissipates pretty rapidly, but I'm concerned that my apartment is still pretty small (500 sq ft). I can get air flowing with window fans, but I'm concerned that it's not adequate ventilation for what I'm doing. The apartment is small, with a pretty open plan, and I'm working on the table next to the kitchen.

This question was prompted by having spent about 20 minutes trying to reflow solder on a board with some weird moisture problem that causes the solder to bubble and spatter. I have no idea what it is (the whole board was covered with some kind of sticky substance before I cleaned it off, but whatever it is seems to be under the existing solder). It might be residual leaked electrolytes from burst capacitors, or it might be some kind of leftover hardcore industrial rosin. Either way, it started smelling awful, and I stopped when it occurred to me that my poor cat was sleeping 15 feet away.

Basically, I don't want to be turning my apartment into a workshop that's hazardous to cats and other living things. How much of a risk have I introduced to the apartment, and what steps can I take to mitigate those? It's not like I can install a fume hood in my living room.
posted by shapes that haunt the dusk to Technology (22 answers total) 2 users marked this as a favorite
 
The "phenolic compounds" in pre '73 capacitors were often if not mainly straight up PCBs, and I think you were endangering yourself at least with the amount of exposure you were getting.
posted by jamjam at 3:25 PM on June 29, 2018


Please do not do this kind of work in your living space. It's not safe, for you or for your cat.

And if you can't install a fume hood or the other necessary protective equipment needed to be safe, you can't do it safely.
posted by Lexica at 3:43 PM on June 29, 2018 [1 favorite]


Is it because of the PCB exposure, or because of the soldering in general? Assuming I leave that kind of stuff alone, am I in the clear with other electronics work in the future, or is it just bad all around? I've heard of people soldering in their apartments, but people do dumb stuff all the time.

Well, fuck. My poor cat. My girlfriend isn't usually home when I'm doing this stuff (which, fortunately, has been very infrequently), but I'm sure stuff lingers. How sick could have I made them from occasional exposure? I know it must depend on concentration, but I don't know if this is something to be immediately worried about. I mean, like, will my cat die from this next month?
posted by shapes that haunt the dusk at 4:03 PM on June 29, 2018


Sorry, by "this" I mean PCB exposure specifically, but any other environmental stuff as well.
posted by shapes that haunt the dusk at 4:12 PM on June 29, 2018


This is one of those cases where it's my turn to say "if you don't know what you're talking about, please don't provide information that is incorrect".

For example, the statement that "The "phenolic compounds" in pre '73 capacitors were often if not mainly straight up PCBs" is flat-out wrong. Yes, PCBs (polychlorinated biphenyls) were used in some capacitors - mostly mains-rated (& above) electrolytics used in certain applications (e.g. motor start, fluoro light pf correction, etc). Outside of a few very early examples from ~ the 1920's, PCBs were almost never used in capacitors in general electronic/radio use.

Granted, the compounds used in normal lower-voltage electros & some other caps are unpleasant irritants - but they're not straight-up toxic like PCBs and friends.

I would also argue that, unless you're either particularly sensitive or doing soldering non-stop for hours on end, flux fumes are not really a problem either (provided you're not using a particularly aggresive flux). Lead from fumes is almost a non-issue - the boiling point is way above soldering temperatures, and its vapour pressure is such that almost none (as in 'some immeasurable quantity below <0.01%') 'evaporates' during soldering.

Any problem with leaded solder is due to either prolonged direct contact (you hold the stuff in your fingers, and absorb miniscule amounts through your skin) or direct ingestion (you put those same fingers in your mouth).

Saying things like "Please do not do this kind of work in your living space. It's not safe, for you or for your cat" is flat-out fearmongering. Sure, don't breathe the flux fumes & do everything you can to mitigate them, and don't leave leaded solder where it can be ingested (as someone who's been soldering for over 40 years, I'd question your technique and habits if you're continually leaving 'splattered solder' lying around) - but otherwise, simple care and hygiene is more than adequate.
posted by Pinback at 4:31 PM on June 29, 2018 [24 favorites]


How's the ventilation? There's little risk if all fumes/vapors are vented to the outside (with a fan). Can you work in front of an open window, with a fan sucking the fumes out?

I would not allow small children to be anywhere near if I'm soldering, lead vapor is a small risk... but I worry less about adults and cats. (In any case I do my soldering and other messing about with non-safe materials in a room that my cats are not allowed into.)
posted by phliar at 4:37 PM on June 29, 2018 [2 favorites]


Ventilation is OK. Three big windows, one of which has a window fan. I work next to a window, but that happens to be the only one I can't open more than a few inches. Hopefully someday I'll have a space where I can keep the cat out, but we're stuck here for the time being.

Thanks so much for the information, Pinback. I really appreciate it. The oldest thing I have is a stereo from around 1972-73, and that had all low voltage (sub 50 V) Elna capacitors. The solder splattering -- it's really just the one board with the moisture problem, but I can't detach it from the rest of the unit and I have to solder sideways in order to get at it (after discharging the big power capacitors, of course!). Like I said, solder on that board has been spattering whenever I apply heat, and this afternoon I noticed tiny little bits of what must be solder on the table. I cleaned them up, but I wouldn't be surprised if I couldn't get it all. It's that sort of thing I'm worried about, and maybe the odd clipped lead that slipped through my fingers and fell on the floor. I'll just make it habit to wipe down the work surface and check the floor in the immediate area.
posted by shapes that haunt the dusk at 5:26 PM on June 29, 2018


Are you sure the solder is spattering? I have soldered, I imagine, tens of thousands of connections and never had solder do that, to my memory. What has spattered though is the rosin (flux), which I don't imagine is great ingested but otherwise not much of a hazard. So I'd avoid doing this where your cat lives its life as it is a bit hard to tell animals not to lick things. You and your partner should avoid ingesting any of this also, but you probably already knew that. Don't solder on your bare kitchen table etc.

Use a sponge/coiled metal solder catcher thing and don't flick excess solder off the iron. Totally hypocritical advice from me, I will admit, but very much worth heeding for both burns prevention and lead bits not getting all over your floor.

If you have young children or friends/family do then you should be quite diligent around all of this, as a child eating a solder offcut or similar would not be good for them at all.

Small filter fans are available that remove the flux smoke from the air as you solder, it may be worth looking at getting one of them as I believe large quantities of the fumes can be an irritant. I have never bothered with this for small jobs and many professionals I used to work with never bothered with it at all.

Seconding that PCB's are highly, highly unlikely to be anywhere associated with the caps you are dealing with. That is poor advice and fear mongering, as is the blanket "don't do this". 1970's gear is quite modern in terms of vintage electronics, take sensible basic precautions and don't worry overly.
posted by deadwax at 7:47 PM on June 29, 2018 [1 favorite]


To temper my previous comment a bit, because I was obviously annoyed when I wrote it: the various fumes from soldering are irritants, other chemicals and materials do have the potential to be toxic or dangerous (but are generally pretty safe under normal soldering/rework conditions), and any or all of them do affect people & pets to a greater or lesser degree, so it's only common sense to minimise them.

I certainly wouldn't recommend doing much soldering anywhere without adequate fresh-air ventilation. A closed-up room/apartment with only recirculating air is not the place to be doing it. But a normally-ventilated room, with natural or forced airflow, and taking care to keep the fumes and splatter away from yourself and pets is fine.

And to correct a mistake in my earlier comment, that I only noticed after the edit window & has been bugging me ever since: "… mostly mains-rated (& above) electrolytics used in certain applications …" is incorrect. I should've said "… mostly mains-rated (& above) paper or plastic foil types used in certain applications …".
posted by Pinback at 7:52 PM on June 29, 2018 [1 favorite]


If you are soldering for hours on end the ventilation will eventually catch up with you as the flux fumes are a mild acid and a respiratory irritant that usually only manifests under chronic exposure. Most hobbyists do just fine blowing the puff of flux away to dissipate it but if you're doing a lot you can invest in a smoke absorber which will grab most of it for you. Allowing outside air to circulate into the room will help a lot too.

Next on the list would probably be to make sure you're using an iron with temperature control (ie a thermostat, not just a power knob) - this is basically the difference between $35 irons and $90 irons, makes a zillion things easier, and helps prevent temperature excursions way above the correct soldering temperature, which keeps the vapor pressure down. For example that spattering you describe sounds a lot like flux + crazy-hot iron. You can combine this with a built in absorber pretty cost effectively (and if you're doing repair, a vacuum assisted desolderimg tool like on that model is basically the greatest thing ever).

Also helpful is a work surface/area that you can legit scrub down - lots of household work surfaces are porous; I wouldn't for example solder on unsealed tile or over a carpet for fear I'd never be able to clean it. In labs and industrial spaces we usually either work on metal or sealed hardwood. As Pinback says above, basic hygiene is your friend as the vast majority of lead transfer will happen via your hands.

But again, unless you are doing FoxConn levels of soldering you are probably good opening a window, turning on a fan, and being good about washing your hands.
posted by range at 8:22 PM on June 29, 2018 [1 favorite]


Agreed with Pinback and range, if you're sensible about ventilation you should be fine. I've been soldering for 30 years or so and usually there are cats around and it's never been an issue.

If your cat is the sort that eats random things off the floor/table like mine, make sure you clean up thoroughly after soldering.

If the smell bothers you, by the way, it's probably the rosin flux used in most solder. I'm very allergic to rosin, so I use a couple of different solders (Kester 331, which is rosin-free but needs cleaning after soldering, and 245, which has a smaller rosin core but can be used on areas that would be hard to clean after soldering) to alleviate this.

Also, at some point someone is probably going to suggest that you use lead-free solder. Don't do that. The lead doesn't vaporize anyway, and the flux in lead-free solder is actually far worse for your health, and you have to use a higher temperature so more flux vaporizes. The government requirements for lead-free solder in industry are to manage toxic waste in landfills, not for the health of those doing the soldering.
posted by mmoncur at 11:39 PM on June 29, 2018 [2 favorites]


Ventilation is OK. Three big windows, one of which has a window fan. I work next to a window, but that happens to be the only one I can't open more than a few inches.

You might want to look if you can fit a flexible pipe to the fan in some way, with the other end at the table where you're working. Something like a sturdy cardboard box that fits over the fan, using velcro strips to keep it in place, and with the pipe attached to the box, so you can put it in place when you're working and remove it afterwards. Also, indeed, a fume filter. I have a pretty small one from Hobby Creek and it's more than sufficient for a lot of my build and repair jobs.
posted by Stoneshop at 2:02 AM on June 30, 2018


Good points already mentioned above.

As an anecdata, my previous employer was audited by OSHA for lead safety. It was a stained glass company.

One of the things the OSHA inspector did, was monitor the lead exposure risks of a worker while soldering lead came using 60/40 solder, for several hours. He probably melted two or three pounds of solder during the monitoring period. The detector was battery operated, with an internal fan, mounted on his chest at pocket level.

There was zero lead detected by the OSHA monitoring equipment.

On the spattering: yes, that can be caused by excessive flux and too-hot irons. But what appears to be "spatter" (lots of little solder balls everywhere), is often separation droplets, a fluid dynamics phenomenon.

Pour milk. Stop pouring. Little balls of milk falling through the air. Those are separation droplets. Separation droplets can be minimized by slowing down your retreat of the iron. Pull away fast, lots of drops; pull away slower, fewer drops.

Also on flux: if the flux fumes bother you, buy solder that is fluxless. Get the good solder, 60/40 or 50/50, not lead free, and a separate liquid flux. There's lots to choose from.

Good luck!
posted by yesster at 2:29 AM on June 30, 2018 [1 favorite]


Get the good solder, 60/40 or 50/50, not lead free, and a separate liquid flux.

Just a quick note, this applies to stained glass etc. There is no solder suitable for electronics that is available for use with a separate liquid flux.
posted by deadwax at 5:12 PM on June 30, 2018


I’m OK with the solder I’ve been using. I have a pen of Kester 186, but I rarely use it. I’ve been wondering if I might have a rosin allergy, because I can get a little congested after soldering for a little while. It seems better if I’m careful about ventilation.

The drops of solder, I think, are mostly the result of excess flux on the board when it was manufactured. The board was covered in sticky gunk when I got it, there’s pitting on all the traces, and pretty much all the solder joints have big holes in them (like bubbles that popped). Applying any heat to the solder causes it to bubble and spatter, but I’m using a Hakko station set to 750, so all I can think is that it’s because of moisture underneath the solder. Adding new solder doesn’t help, because it just gets holes in it like the old joints. I’ve tried heating the joints to boil off the flux. Fluid bubbles out the side, but it never goes away before I get worried about damaging the board. This might be enough of a departure from this question that it warrants its own thread, but it’s a problem I haven’t been able to solve.

What does bubble out is dark orange and smells fishy. I’m assuming that’s flux, because I don’t know what else it would be. Trying to boil that stuff off is what prompted me to post this question. Like I say, it may warrant its own thread, but what’s going on here? Is my risk here that it’s a particularly harsh kind of flux?
posted by shapes that haunt the dusk at 7:49 PM on June 30, 2018


750 deg F is kind of hot, actually. I keep my iron set to ~650 deg F for 60/40, and only turn it up if there's a lot of mass to heat up. When you're resoldering old joints (or new joints for that matter), generally the joint will bubble for a few seconds and rosin will form a pool around the solder joint. If the bubbling doesn't ever settle down that could be an indication of too much heat.

Old rosin doesn't smell fishy to me but it does have a, er, danker kind of smell. Dark orange sounds right. If you're getting 'fume flu' then you should definitely be more deliberate about ventilation. I solder in my apartment's bathroom since it has an exhaust fan.
posted by Standard Orange at 8:25 PM on June 30, 2018


I too do some small-electronics hobby soldering in a 500sqft apartment in front of a cracked-open window, and I use a USB fan to help draw the fumes away from me.
posted by Xany at 9:58 PM on June 30, 2018


Get the good solder, 60/40 or 50/50, not lead free, and a separate liquid flux.
Just a quick note, this applies to stained glass etc. There is no solder suitable for electronics that is available for use with a separate liquid flux.
A slightly different quick note ;): 50/50 rosin-core solder is tinsmith's solder, not electrical solder.

Fantastic for soldering brass/copper/tinplate/nickel plate, or some hardline/heliax/waveguide connectors - but nobody's used it for electrical or electrical work since 60/40 became common in the 50's. Too far from eutectic; too easy to make poor joints; not great with some board or contact platings.

I'm still using the roll my now-retired electrician father left in his toolbox after switching during his apprenticeship - but to build shielding cans & the like…

(I make this point because I was left shaking my head after reading posts on an audiophile forum where they recommended some random 50/50 solder - purely because the rosin type number on the roll matched some supposedly Magic Audiofile Solder…)
posted by Pinback at 4:02 AM on July 1, 2018 [1 favorite]


And yeah, 750F/400C is stinkin' hot - I almost never go above 325~360C or so for normal board joints. I'll very occasionally wind it up to 400C for heavy groundplanes & the like, but I know I should really be pulling out a bigger iron (or walking downstairs to use the 120W firestick in the garage).

If you're needing to have your Hakko wound up that far for normal joints, I'd suggst it's either out of calibration (& tip temp is actually lower), or you're using the wrong tip shape/size for the joint. Personal opinion: cone-shaped tips are terrible; I prefer a 1.2mm chisel for most through-hole & 0805/1206 SMDs.

Assuming the temperature is accurate, at that sort of temperature your 'splattering' is probably due to old & self-degraded natural rosin flux (over time it crystallises & separates into solids & some oils, with probably a bit of water too) trapped in the joint, rapidly burning off.

I know the 'fishy' smell you're talking about. Again, it's well-burnt old-school natural rosin flux that's degraded over the years. The dark orange/burnt fishy smell also indicates your iron temperature is way too high.

Based on what you've said, my initial suggestions would be to check your tip size/shape (I think it's Hakko that has a rather good tip selection guide, so look that up), wind the temperature down to maybe 360C (680F) max, and don't try to "boil that stuff off" - melt the joint quickly, use a sucker, and clean up any old flux with IPA on a pad (tip: makeup removal pads &/or cotton buds are good for that. But don't tell my partner…)
posted by Pinback at 4:48 AM on July 1, 2018 [1 favorite]


We're pretty deep in the weeds now but I'd also add that, for me anyway, any time I try cotton balls/q tips/etc to remove flux I end up with scraggly cotton shreds everywhere and ultimately have two things to clean up instead of one. If you have really baked-on flux you might have luck scrubbing away with alcohol and the stiff acid brushes plumbers use so you can gently dab with cotton after. It's also possible I'm some kind of barbarian and you won't have this problem.

Having taught at least a couple thousand people to solder I'd say about 98% of the time having a too-hot iron indicates a technique problem, with the remaining 2% being mostly an oxidized tip (typically a runaway problem caused by a too-hot iron...)

One of the challenges in teaching intro electrical soldering is that everyone's instinct is to use the iron like a quill to deliver solder to the joint, which is bad technique and won't work reliably. But some tutorials/instructors overcompensate and tell you to never put solder on the iron, which is also wrong. For soldering and especially for desoldering you need a dab of solder on the iron tip - not to become part of the joint but as a thermal conductor, giving you a way better thermal contact area. If you don't have that bridge, 660F will definitely feel like it's too low. (For clearing some stubborn clogged through-holes the best solution is paradoxically to add solder, to get a better thermal path to the middle of the hole.)

This video has its issues (mostly of the pedantic, technically-correct-is-the-best-correct variety) but is also I think 100% accurate, a rarity in this genre.
posted by range at 5:08 AM on July 2, 2018 [1 favorite]


Thanks for the heat advice. This is my first temperature controlled station. Someone said “ah, I just leave mine at 750,” and I’m inexperienced enough that I just said “oh, OK” and set mine there. Fortunately, I don’t seem to have done any damage to pads or components. I’ve dialed it back and it works just fine, so I guess I can chalk it up to inexperience. I have a good selection of chisel tips up to 3mm, and I’ve been trying to use the right size for the task.

Anyway, on most boards things have been fine. It’s just that one board (the tone amp, specifically) that remains problematic, and that’s the only one where there’s any bubbling. The problem persists even with a lower iron temperature (again, only on that board). I can heat a joint, but it bubbles and continues bubbling well after I pull the iron away; I think it only stops because the solder cools. Obviously that’s not good for preventing cold joints. When I’ve said I can “cook” it off, I mean I can lift the iron up and hold it next to the point, and it’ll continue bubble and pop. This is what it looked like when I first got it. It was clear that the flux had never been cleaned off, so I went at it with IPA and a toothbrush (yeah, I’ve had an awful time with shredded Q tips, so I’ll look into those plumbers brushes, thanks!). Still, I can’t stop the solder from behaving like this.

Anyway, I I think I’ve gotten the right combination of fans to minimize smoke and bad smells (that presumably indicate unhealthy stuff). There was some odor when I ran the unit for an hour yesterday, but I’m assuming that’ll go away over time; per my last thread on this, I’ll probably leave it running next to a window for a while once it’s fixed.
posted by shapes that haunt the dusk at 10:34 AM on July 2, 2018


Ah, a picture's worth 1000 words. There's something about boards made with that particular type of old dark phenolic that commonly behaves like that. I don't know if it's the board material itself (e.g. an aging/breakdown product from the phenolic), something to do with the construction (e.g. the glue used to bond the copper to the board cooking, or somehow lots of flux getting trapped in the component hole/internal board material), the heavier flux commonly used at that time (which, as far as I can tell, was often cheap unmodified rosin unlike the cleaner rosin or modified/artificial rosins used since the later 70's/early 80's), or what - they do that, it stinks, and it's really easy to damage the board.

About all you can do is be careful with heat & soldering time, try to minimise both, and absolutely minimise the amount of work on the board. On some boards I'll cut component leads on the top & do (terrible video alert) 'quig-style' joints rather than risk damage, though it's not a technique I normally like to use.

Often a stronger flux cleaner will work a lot better than IPA. IPA + ~10% water (not rubbing alcohol, with is ~30% water) can work slightly better than straight IPA, but you need to dry after use (either with an IPA wash, or mild heat). On really bad cases I've used acetone, but it does tend to at least dull the surface of the phenolic, so I presume it's softening it too (and it's also likely to damage any plastic components).

On really really bad cases, I've been known to use a little TCE from my long-hoarded bottle - but that's nasty, nasty stuff; not recommended; kids, do not try this at home; etc.

The makeup pads I use have a woven cover over a pad of absorbent material, so generally don't leave much if any fluff behind. The trick with cotton buds is to use them for spot-cleaning only, & spin them in the direction of winding so they don't unravel.

And yeah, I've overlooked the basics and assumed you knew good soldering practice. Range's advice is good, and the video they've linked is good too (even if it does use the incorrect inherited-from-the-French-via-the-Scottish-and-missed-out-on-the-whole-"re-Latinisation-of-English"-pronunciation thing 😉).
posted by Pinback at 8:52 PM on July 3, 2018


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