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I watched the YouTube section of soldering tutorials and had significant troubles when replicating on my own, even with SAC 305. I then switched to 60/40 and suddenly soldering became easy.

I am working with gloves to not touch the lead directly. At the same time, I need to rotate or reposition the perfboards/PCBs into the position I need. So I am touching the lead, the perfboard, soldering station, etc. with the same surface both when I am wearing gloves but also when I take them off. I clean the solder joints with IPA, but not all the surfaces I touched.

I also noticed very tiny shiny solder particles laying around the table. I think solder spattered because I was running the iron too hot at 355°C. Beside the visible particles, are there also invisible ones I am not seeing?

Is this just me overthinking the problem or is there any additional cleaning procedure I should take after soldering with leaded solder? The lead levels in blood that are consider toxic are crazy low at 0.1 mg/L but I am pretty sure that not all lead ingested goes into the blood system. Thank you for your comments.

ocrdu
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sanjihan
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    Lead is not magic death cooties. You can handle the board and the solder itself with your bare hands - you'll be fine. If you still feel nervous, wash your hands with normal soap before eating. – brhans Jun 23 '22 at 12:16
  • 355C is high unless you are soldering big pins on a ground plane, for example. For leaded solder, 260-280C is fine for most connections. You'll also notice benefits such as less splatter from vaporizing flux, less melt-back on wire insulation, fewer burnt parts, fewer lifted pads, and longer tip life. – vir Jun 23 '22 at 17:17
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    @brhans ‘magic death cooties’ I darn near wet myself! Just bout everyone I know have been easing leaded solder for over 50years without any hazmat precautions. We knew not to eat the stuff. Tetra Ethyl lead probably did more damage. – Kartman Jun 24 '22 at 01:32
  • @Kartman A few millions deaths per year less and some ~10 IQ points less for the entire population. – winny Jun 27 '22 at 13:35
  • For lead free hand soldering with an iron SN100C is generally easier to work with that SAC305. Aside from the higher temperature I don't find it significantly worse than 60/40. The advantage of lead is that it's more that it's very forgiving of bad habits like too little flux or using the wrong size tip. For hot air the higher temperature is significantly more annoying though. Leaded solder isn't super dangerous but I understand why you may not want to bring it into your home. – user1850479 Jun 27 '22 at 13:51

1 Answers1

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I then switched to 60/40 and suddenly soldering became easy.

RoHS solder melts around ~220° and leaded around ~190°, so leaded is much easier to work with and generally recommended for beginners.

I am working with gloves to not touch the lead directly.

No need for that, it will just be cumbersome and in the way. You need to be as dexterous as possible, particularly the hand which holds the tweezers and solder wire.

You don't need to worry about lead poisoning etc, just don't get it in your mouth. The main health concern is the flux, not the lead. Always wash your hands after soldering and that's about it.

Much more importantly, make sure not to inhale the vapors. Professionals use a fume extractor, hobbyists maybe a fan or "hold your breath". For larger jobs only the fume extractor is viable.

I also noticed very tiny shiny solder particles laying around the table. I think solder spattered because I was running the iron too hot at 355 degrees C.

Yeah solder splatter happens, you might be using too much solder or too thick solder wire. Ideally the solder tip shouldn't be touching the solder at all (an utopia, rarely possible in practice). You need to remove these while cleaning the board, since they might otherwise short components. They are harmless for your health unless you decide to eat them.

Beside the visible particles, are there also the invisible ones I am not seeing?

Again, there is the vaporized flux in the air, which is the only thing you should be worrying about. Not the lead.

Is this just me overthinking the problem

Yes. You might want to check out this post: What type of solder is safest for home (hobbyist) use?

The lead levels in blood that are consider toxic are crazy low

Unless you've been eating leaded solder, there's no reason to believe otherwise. Don't eat it.

Lundin
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  • Thank you for you answer. Since I am just starting out I worked outside on the porch and used the "hold your breath" with slow exhaling method you mention. After I finished the board I was working on, I took a wet wipe and cleaned the surroundings. I was surprised by the amount of very tiny shiny particles I found on the floor even 1m away from the desk. The amount was considerably higher than in other sections of the porch. – sanjihan Jun 25 '22 at 08:43
  • Also, I think tip cleaning wool needs to be surrounded in an enclosure because it acts as a spring and splatters the solder around when you use it. – sanjihan Jun 25 '22 at 08:46
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    @sanjihan For cleaning smaller tips I recommend a wet sponge. Cleans better and no "spring" effect. Either way, you are supposed to gentle swipe the tip across it, not bury the tip deep inside. – Lundin Jun 27 '22 at 09:15
  • Damp sponge, not "wet" sponge. Soak the sponge in water, then squeeze it out. When you can't squeeze any water drops out of it anymore then it is ready. – JRE Jun 27 '22 at 13:29
  • @JRE It doesn't matter much unless you have the habit of stabbing it with the tip, which you shouldn't be doing no matter if it's a wet sponge or brass sponge. Just a quick swipe right-left across the surface. – Lundin Jun 27 '22 at 13:37