soldering fumes toxic?

Thread Starter

lotusmoon

Joined Jun 14, 2013
227
I am fairly new to electronics. As soldering equipment was freely available I had not thought there were health hazards from it. I have had some eye problems since I started on my project. Then on watching some you tube videos on soldering I found I needed goggles to protect my eyes and a fan to remove fumes. I now have a fan and goggles, but am interested if there are solders that are less toxic than others. Also if soldering is big time toxic or if it is a minor hazard.
 

wayneh

Joined Sep 9, 2010
17,498
I'd say the overall risk is fairly minor unless you do it all day long for a job, and/or you have poor ventilation.

The biggest danger is the lead, since you cannot detect it and it is a cumulative toxin.

The pain in your eyes is due to the flux, which you can smell and sense. It may not be good for you either but is easy to avoid since you can see and smell it.

I have to admit that I don't wear safety glasses when soldering. I'm normally pretty cautious about safety, for instance I always wear ear plugs when using an engine, but I just don't like anything that restricts my vision. I have enough trouble working on small things that I use a magnifying glass and a bright light to help. Wearing a goggle would make it one step more difficult. This is all a lame excuse, but that's me.

Oh, and no cocktails until the soldering iron has cooled. ;)
 

Thread Starter

lotusmoon

Joined Jun 14, 2013
227
can the flux get on my hands from holding the solder and then if i rub my eyes get in them that way. my left eyelid is quite swollen.
 

studiot

Joined Nov 9, 2007
4,998
If your fan is working properly you should not need goggles as well, perhaps you are extra sensitive?

However the potential hazards of soldering fumes should not be played down, some fluxes are more dangerous than others.

Most places of work now use a fume cupboard for soldering or at least a fume extraction hood.

Remember also to wash your hands after handling solder, and other compounds, before eating, rubbing your eyes etc. The flux in particular is normally an acid flux so keep it out of your eyes.
 

PackratKing

Joined Jul 13, 2008
847
can the flux get on my hands from holding the solder and then if i rub my eyes get in them that way. my left eyelid is quite swollen.
It is possible to be so allergic in that instance, that the residue left on eyelids from random smoke, if rubbed in, could produce those symptoms...
Best bet is your ventilator to outdoors.,..
 

BReeves

Joined Nov 24, 2012
410
can the flux get on my hands from holding the solder and then if i rub my eyes get in them that way. my left eyelid is quite swollen.
Been handling solder and smelling flux for almos 60 years, if it's toxic I would be dead. Only thing I remember bad was when I was about 10 I thought it was a good idea to stick a piece of acid core solder in my mouth while making a tin boat.
 

Metalmann

Joined Dec 8, 2012
703
Been handling solder and smelling flux for almos 60 years, if it's toxic I would be dead. Only thing I remember bad was when I was about 10 I thought it was a good idea to stick a piece of acid core solder in my mouth while making a tin boat.


I remember doing the same thing with the acid core.:eek: Only did it once.
 

mcgyvr

Joined Oct 15, 2009
5,394
flux fumes are basically just a mild irritant.. more information provided in the MSDS sheet for that specific solder/flux. Soldering temperatures are not high enough to vaporize lead so the "smoke" is basically burnt of the flux. A simple fan to blow it out the window is more than enough..

However... Think of soldering as a microscopic lead particle volcano...Lead will easily coat all surfaces within a 3 foot radius or more. (I know..we test for it routinely at work with lead swabs,etc...) You should always wash hands before putting them in your eyes/mouth,etc... It gets on your clothes and everything. Lead in high enough quantities is obviously a dangerous element but the hobbiest will more than likely never be exposed to it long enough to do any known harm.
So obviously wipe everything down/wash hands/just be clean in general.

And yes your eye irritation could easily be from flux fumes/bad solder "hygiene" but it also might not..
 

GopherT

Joined Nov 23, 2012
8,009
can the flux get on my hands from holding the solder and then if i rub my eyes get in them that way. my left eyelid is quite swollen.
Yes, rubbing flux into your eye will cause your eyes to burn, turn red and swell up.

Rinse them with water (holding the eyelid open) in your shower for 15 minutes. See your eye doctor.
 

GopherT

Joined Nov 23, 2012
8,009
Riddle:
An undergraduate chemistry student and a graduate chemistry student walk into the bathroom. Which one is the graduate student?

Answer:
The one who washes his hands before urinating.

Keep your hands clean, my friends!
 

DerStrom8

Joined Feb 20, 2011
2,390
It's important to note that acid flux should not be used in electronics soldering. It is mainly intended for plumbing applications.

However, the most important things for you to do to keep yourself safe while soldering are:

a) Use proper ventilation. Make sure you're in a large room with an open window, and a fume extractor (even if it's just a fan set up to draw the smoke away from you)
b) Do not stand over the part you're soldering, or else the smoke will get in your eyes. This can also irritate them and cause the problems you mentioned.
c) WASH YOUR HANDS! This is very important, as most solder contains a fair amount of lead. Both fumes and physical contact can cause health issues.

You can buy lead-free solder, but it does not work well and I do not recommend using it at all. Plus, you'd still have a problem with the flux. Just use common sense. Keep yourself away from the smoke as much as possible, and clean up frequently, even while you're still working.

I follow these rules and have never had a problem. Oh, it's also very important to NEVER melt ANYTHING except for solder with the soldering iron. Be careful when soldering near wires, and make sure not to touch the iron to the insulation. It will burn onto the iron tip and will continuously release toxic, or at least irritating fumes.

Regards,
Matt
 

Thread Starter

lotusmoon

Joined Jun 14, 2013
227
Thank you for your information it is very useful. I have been using lead free solder is it better to use colophony free solder or is it possible to get lead free and colophony free solder?
 

DerStrom8

Joined Feb 20, 2011
2,390
Thank you for your information it is very useful. I have been using lead free solder is it better to use colophony free solder or is it possible to get lead free and colophony free solder?
Don't use [anything]-free solder. It's more difficult to use and the connections aren't as good. They also tend to crack and fall apart over time. Use real 60-40 lead-tin solder, I use the stuff with a rosin core. Just follow the suggestions in my previous post to avoid the fumes, and you should be fine with using ordinary solder.
 

PackratKing

Joined Jul 13, 2008
847
Don't use [anything]-free solder. It's more difficult to use and the connections aren't as good. They also tend to crack and fall apart over time.
:confused: I have used lead-free, or 95/5 silver-bearing solder exclusively, long before our dear nanny gubbermint [ sarcasm intended ] nixed the use of lead to solder copper plumbing...

I have found same to be excellent for electronic soldering, and have yet to encounter any " whiskering "
I don't have any issues with my el cheapo dollarstore iron melting the stuff... Am I that stubborn ???:D to be not seeing trouble that others seem to have with it ??
Not wanting to be snarky here, just trying to keep up...:p
 

Stuntman

Joined Mar 28, 2011
222
Just a couple thoughts/experiences as about everything else has been covered.

I have, on more than one occasion, gotten definitively shakey/cold/sickly feeling after soldering for long periods of time (hours on end). I have to assume some, myself included, can be sensitive in this way to solder fumes. I can say that once in a while, I notice some mild irritation of the eyes as well if I happen to get a big whiff of smoke.

I can tell you that fume extractors have not impressed me in the past. Generally, they have to be close enough to your workpiece to be in the way. Instead, I've found a small fan blowing across the the workpiece does a great job of keeping smoke and fumes out of my face.

As others have said, it's a no-brainer to give your hands a wash before eating. Heck, if I solder a bunch in the morning an leave for lunch, I can usually feel all the residue on my hands.

Just use a little forethought and you won't have to deal with these issues.
 

DerStrom8

Joined Feb 20, 2011
2,390
:confused: I have used lead-free, or 95/5 silver-bearing solder exclusively, long before our dear nanny gubbermint [ sarcasm intended ] nixed the use of lead to solder copper plumbing...

I have found same to be excellent for electronic soldering, and have yet to encounter any " whiskering "
I don't have any issues with my el cheapo dollarstore iron melting the stuff... Am I that stubborn ???:D to be not seeing trouble that others seem to have with it ??
Not wanting to be snarky here, just trying to keep up...:p
In my experience lead-free solder has not worked well. It melts at a higher temperature and takes longer to cool, which allows parts to move slightly before solidifying in place. This can cause cracks and air bubbles to form in the solder. Honestly I have no idea how you've avoided this. If you could tell us your secret, it'd be appreciated :p

In all seriousness though, nothing beats 60-40 lead-tin solder, and if it's used correctly it's perfectly safe.

Matt
 

PackratKing

Joined Jul 13, 2008
847
I think the only thing different about my technique, is adequate heat... I have definitely noticed if I am in a hurry with the silverbearing, it definitely cools wrong, and leaves "cold" joints.
This I use only to solder terminals to wire, or spade terminals to a pcb, or tinning wires to clamp into a switch, if I'm not soldering direct, and these stay rigid until the solder sets up...

Otherwise, when doing any connections to a pcb, especially in camera related work, I use eutectic .020 63/37, of which I have about 6 lifetime supply...:D
 

WBahn

Joined Mar 31, 2012
30,077
In all seriousness though, nothing beats 60-40 lead-tin solder, and if it's used correctly it's perfectly safe.
Curious as to why you tout 60-40 over 63-37 eutectic?

I know it is slightly more expensive -- though I've generally found that I can find it at a surplus store for the same price. Though I don't know if that is still true because I pretty much bought a lifetime supply about ten years ago when a surplus store clearly didn't realize what they had and I got 0.008" 63-37 for something like $2/1lb spool, so I bought every one they had.

I believe I have noticed faster solder times and better joints, but I seldom have joint problems (my solder joints -- let's not talk about my hip and knee joints) to begin with, so that could be an illusion and, even it it's not, it's at best a marginal improvement.
 

mcgyvr

Joined Oct 15, 2009
5,394
Curious as to why you tout 60-40 over 63-37 eutectic?

I know it is slightly more expensive -- though I've generally found that I can find it at a surplus store for the same price. Though I don't know if that is still true because I pretty much bought a lifetime supply about ten years ago when a surplus store clearly didn't realize what they had and I got 0.008" 63-37 for something like $2/1lb spool, so I bought every one they had.

I believe I have noticed faster solder times and better joints, but I seldom have joint problems (my solder joints -- let's not talk about my hip and knee joints) to begin with, so that could be an illusion and, even it it's not, it's at best a marginal improvement.
The ONLY difference is 60/40 is cheaper and has a slightly higher "freezing point".

If he isn't skilled enough to solder with lead free then 60/40 is probably a better choice for him anyways.. Virtually all electronics now-a-days are soldered with lead free.. (unless you are ROHS exempt you'd better be using leadfree)
 

wayneh

Joined Sep 9, 2010
17,498
Riddle:
An undergraduate chemistry student and a graduate chemistry student walk into the bathroom. Which one is the graduate student?

Answer:
The one who washes his hands before urinating.
Haha, you could easily reformulate this joke for chefs. Ever process hot peppers and then touch ... anything? You don't forget. :eek:
 
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