I have never seen this many warning signs on anything that I have ever bought. I know that I’m supposed to suck away the soldering fumes, even if I use lead free solder, which I’m going to do with a 12 volt computer fan fitted with a carbon filter. But what the heck is in the flux that will damage my nervous system… 💀 putting my mask back on… 😷
Hi! I have a Masters in electrical engineering, I have more experience soldering than probably most people here.
Flux is not that dangerous as long as you don’t get it IN your body. Your computer fan + carbon filter is perfect, because the flux fumes are highly irritating if you breathe them in or get them in your eyes. But flux is mostly just pine rosin mixed with solvents. (To be clear, rubbing alcohol will also damage your nervous system if you ingest or breathe a lot of it. Flux isn’t particularly unique).
The risk of lead fumes is incredibly overstated. Lead doesn’t even start to vaporize until well into the thousands of degrees, you will never be soldering anywhere near that temperature. You’re at higher risk of getting small specks of lead stuck to your hands and then accidentally in your mouth, which is why I always recommend washing your hands immediately after soldering or just touching the equipment.
So your saying I shouldn’t be holding the solder in my mouth as I hold the iron in one hand and the component in place with the tweezers in the other hand? Interesting
Most solder is lead-based. At over 900 degrees Fahrenheit, lead fumes are breathable. Lead poisoning is bad news.
Use the correct heat setting and make sure you work in a well-ventilated area or use a respirator.
I don’t have numbers to back this up, but I have medium doubts that most solder used in electronics is lead based these days. There are plenty of lead free options available, and electronics as a whole are moving that way. Anything with an RoHS label will be lead free for example. If products in these categories are sold in the EU they have to meet the standard.
Edit: This is not an argument against ventilation though! You should still have some kind of air handling on account of the flux fumes, and also any other metal fumes that may not be good. Better than lead doesn’t always mean completely harmless.
Copy that! Looking up recommended temps for my solder, the iron model and work type.
Just FYI this is a hugely overstated risk. You can melt leaded solder with a Zippo (~350F) while lead only begins to produce a tiny amount of point vaporization at ~900F, so the safe range for your iron’s temperature is large.
You’re doing the right thing setting your iron to match the solder. Beyond that, just thoroughly clean your station and wash your hands after you’re done.
Separately, I don’t think rosin is all that harmful, but it’s certainly very irritating if the fumes get in your eyes. Your basic fume hood should be more than sufficient.
Those brain cells just made life complicated.
All people that use flux will die eventually. You have been warned!
I’ll just flex myself out of that
As you mention, use a small fan filter to draw away the fumes. If you can smell the flux vapors, you don’t have enough ventilation (although most people won’t care). Unless you do long sessions I rarely see people wearing masks or gloves but if you are confortable doing so then yes that’s a good idea.
One thing is glasses. Especially when inexperienced, it can happen that you can fling around small solder blobs by accident. You don’t want that in your eyes.
I would suggest not avoiding flux. It’s basically easy mode compared to without. Even if you use flux core solder.
Thanks! Great input on the glasses! I wear prescription glasses daily, but I’ll grab a pair of protective ones tomorrow. 😊
I’m not a professional solderer or anything but I had a training course by a bunch of people who do it to a very high level, like they spend all day pulling off and examining chips on boards, etc. They said that you don’t normally need flux, you just need to apply hear properly with the iron. During the whole course the only time they used flux was when they were re-soldering a chip.
Plenty of solder wire is flux core these days. It’s basically a metal tube with flux inside. Back in the day this wasn’t the case so you had to add the flux yourself. Nowadays it’s typically not needed so long as you size your solder gauge correctly. Super fine solder doesn’t have much or any flux, and if you’re trying to solder huge pads or vias you’re gonna have a hard time.
Flux helps heat transfer. Think of it like oil in a frying pan. It conducts the heat from the iron to the solder joint better than just bear contact. For non-delicate components it doesn’t matter too much, but if you’re working on ICs you don’t wanna cook them before all the joints are good. There are also some oxidation inhibiting properties. Ya don’t want oxidation on your joints!
Thanks for the valuable input! I might just leave the flux pen rest until really needed.
I think they are trying to tell you not to eat it. I ate a few leaded solder balls before and I’m still here though, so there’s that.
Don’t eat or touch or inhale. Treat as hazardous waste.
Basically wear gloves and mask. Dispose of in the special bin at you local garbage dump.
How’d they taste?
Not much of anything. It’s more about the texture, perfectly smooth except for the part where it touched the surface it was on when it solidified where it’s like a little back scratcher but for your tongue.
You did not eat leaded solder balls. Did you? Wait. Is that the secret to immortality?
the first symbol is letting you know the warnings only apply if you’re Iron Man
…then, we might have a problem 🤖
