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Offline CentaurTopic starter

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Lead free solder
« on: June 16, 2008, 08:47:22 PM »
I am looking to buy lead free solder, mostly because I live in an apartment so I will be working indoors and not in a garage or basement and I want to avoid lead fumes.  I am purchasing a fume extractor designed for lead free solder (way cheaper than fume extractors for leaded solders).

What is the benefit of the various lead free solder compositions (Sn96.5Ag3.0Cu0.5 vs Sn99.3Cu0.7 vs Sn97.0Ag0.2Sb0.8Cu2.0 vs Sn97.0Cu2.0Sb0.8AG0.2 vs Sn95Ag5) and do I still want to still stick with 22 - 25 gauge solder?

The Sn96.5Ag3.0Cu0.5 seems to be the most common, why (should I just get this composition)?  Also what is the difference between cored and non-cored solders and more importantly what is the difference in their performance and applications?

Anything else I'm missing that's important when choosing a solder?

Any intelligent fool can make things bigger, more complex, and more violent.  It takes a touch of genius - and a lot of courage - to move in the opposite direction.  ~E.F. Schumacker

Offline coldkryten

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Re: Lead free solder
« Reply #1 on: June 16, 2008, 09:46:15 PM »
This is a bit of a myth actually.  The fumes from solder are almost entirely due to the flux, not from the metal itself.  Lead solder fumes contain virtually no lead.  Lead-free solder requires higher temperatures and is harder to work with, especially with a cheap iron, and generally needs more flux and more aggressive flux to work properly.  This means that at least in terms of fumes, lead-free solder is worse for you than leaded.

Lead exposure from solder is primarily through skin contact (minimal) and eating without washing your hands (stupid.)

Also, cheap fume hoods only absorb a portion flux fumes, so make sure you still have an open window and possibly fan nearby as well.

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Offline bens

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Re: Lead free solder
« Reply #2 on: June 17, 2008, 12:19:00 AM »
As coldkryten has said, when you are soldering, you are not generating lead fumes.  The smoke you see is vaporized flux. 

Leaded solder used in electronics work is mostly tin, which has a very low melting point (231C), with some lead mixed in (the melting point of lead is 327C).  Together, the alloy has a melting point slightly lower than each of its component metals, which makes it ideal for creating electrical connection with relatively low-temperature soldering irons that don't damage the components being soldered.

Next note that the boiling point of tin is 2270C and the boiling point of lead is 1740C.  The solder won't come anywhere near these temperatures while in contact with the soldering iron, so there is no where near the sufficient energy needed to vaporize the lead.  I tried looking online for references to lead in solder fumes and I came across two links.  The first was the wikipedia article on solder fumes:

http://en.wikipedia.org/wiki/Solder#Solder_fumes

However, the section seems to be taken directly from the web page of a company that sells air purifiers:

http://www.sentryair.com/solder%20fume.htm

And all the other information they have in support of the harm of leaded solder fumes seems to be either out of context or incomplete.  Everything else I can find supports the notion that there is virtually no lead in solder fumes generated from a standard soldering iron at 300C (which is what one would expect just from understanding the chemistry of the process).

- Ben

Offline lkik

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Re: Lead free solder
« Reply #3 on: June 17, 2008, 12:55:46 AM »
i all ways solder in my room with no ventelation it has not killed me yet but i have  tto die of some thign

Offline izua

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Re: Lead free solder
« Reply #4 on: June 17, 2008, 01:24:12 AM »
i has a hunch it's bicoz of someonez who likes grammer.
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Offline Asellith

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Re: Lead free solder
« Reply #5 on: June 17, 2008, 01:52:49 PM »
The warning that always scared me was the one about causing birth defects in your children. I care less about myself more about having a handicap kid because of bad soldering habits.
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Offline bukowski

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Re: Lead free solder
« Reply #6 on: June 17, 2008, 02:46:52 PM »
I think it's probably a case of "its ok in moderation", kind of like an occasional cigar and scotch is ok. If you plan on soldering for several hours a week, it would be a good idea to use unleaded solder.

Offline dsheller

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Re: Lead free solder
« Reply #7 on: June 17, 2008, 04:08:57 PM »
The warning that always scared me was the one about causing birth defects in your children. I care less about myself more about having a handicap kid because of bad soldering habits.

I'm assuming you're a male based on the name Johnathan... so I doubt bad soldering habits would really hurt you. Due to your reproductive cells being constantly created... a woman on the other hand is born with all the eggs she'll ever have, so they're worse off than us... but then again I'm not a doctor so don't quote me =)

Offline emmannuel

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Re: Lead free solder
« Reply #8 on: June 17, 2008, 04:15:31 PM »
I switched from lead free to leaded because I just had such a hard time soldering.

I was more likely to melt the board or components I was trying to solder than the silver solder   >:(

Offline bens

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Re: Lead free solder
« Reply #9 on: June 17, 2008, 04:16:19 PM »
Lead creates birth defects by interfering with maturation and development in the fetus/child.  To the best of my knowledge, it does not become lodged in or mutate our reproductive cells.  I imagine lead would cause problems for a fetus only if the mother has unsafe levels of lead in her bloodstream as the fetus is growing.

- Ben

Offline Admin

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Re: Lead free solder
« Reply #10 on: June 19, 2008, 08:48:43 AM »
I've become paranoid lately of using leaded solder . . . my hands come into contact with it and perhaps I accidentally ingest it occasionally . . . but of course, there isn't much scientific knowledge of the effects of minimal amounts of lead on an adult . . . still, I'm paranoid . . .


As for solder thickness, that depends on the job. For SMD, I use really thin solder, for male headers I use really thick solder.

As for flux, I prefer 2%. I've tried 3%, but then I must constantly clean the tip and the flux splashes everywhere on my board as I solder . . .

Offline Rand alThor

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Re: Lead free solder
« Reply #11 on: June 19, 2008, 02:51:02 PM »
Well, lead solder and lead-free solder are both poisonous. Most lead-free solder contains 5% Antimony, which is poisonous as well. So really, by handling lead-free solder, you're still handling toxins. Not in the same quantities or proportions, of course, but still. Also, isn't tin poisonous? Didn't the tin man from the Wizard of Oz have to be replaced because the original got tin in his lungs and was hospitalized? Or was it aluminum that did it?

Offline bens

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Re: Lead free solder
« Reply #12 on: June 19, 2008, 02:59:05 PM »
http://en.wikipedia.org/wiki/Buddy_Ebsen#The_Wizard_of_Oz

Apparently it was aluminum.  My guess is that pretty much any metal is bad for you when it's in powderized form and coating the inside of your lungs...

Offline Admin

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Re: Lead free solder
« Reply #13 on: June 19, 2008, 03:17:33 PM »
*Anything*, no matter what it is, can be poisonous in certain quantities. Even vitamins, when overdosed, can make someone really sick . . .

My concern is the rate at which it can permeate my body, and the quantity needed, to mess me up . . .

Lead tends to cause drain bamage, something I worry about in my line of work :P

I'm sure the other toxins affect other parts of the body, probably parts I'd care about less . . . (but I'm just guessing at this point)

Anyway, there are no studies out there that I'm aware of that knows the full affects of soldering on robot engineers :P

Offline Rand alThor

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Re: Lead free solder
« Reply #14 on: June 20, 2008, 12:09:53 AM »
Quote
*Anything*, no matter what it is, can be poisonous in certain quantities. Even vitamins, when overdosed, can make someone really sick . . .

True, true, but softer metals are more poisoners because they can brush of on your hands and get into your bloodstream (usually via mouth). Of course, theoretically, you could get iron/stainless steel poisoning, but have you heard of anyone dung because they were rubbing their new fridge? :P

But also theoretically (and getting back more on the point ;)), If you have anything in small (enough) quantities, it won't hurt you. Take me, for example. Today I had my first soldering experience. I had to do it in the garage because my Mom wouldn't let me do it in my bedroom. I had the big garage door open, and the side door open. So I think if you have enough ventilation, you should be OK anyway. But you don't have a garage, as you mention above (or, at the time of this writting, below  ;)). So my suggestion is if you have an AC intake in your apartment, cover that up, or at least put one of those air purifiers/ lead fume removers by that, because chances are that the AC is for a bunch of apartments. Go to a well ventilated room, preferable one with two windows (so a breeze can get through, the way I figure it), etc. Or................

If you have a to of money to spend, you could take the super-duper-overly-extravegent-crazy-sort-of-thing-I-would-do-if-I-had-the-faculties-approach, which happens to be.....

Either get a really big safe, or preferably a steel plated environed room. Buy an environment suit, with breathing. Drill a hole in the steel plating for the breathing tube to go through, tread the tube through, connect it to the breathing machine doohicky, and seal the hole. You can do this with putty, duct tape, hot glue, and aluminum foil (and solder, if you have any ;)). Set up your workbench in the safe/environment room. If you bought the safe, remove the lock. I find a screwdriver works fine. If you need to cover the gaping hole left by the lock, buy a littler, smaller safe and superglue/duct tape/ google the little safe on. If you're broke at this point, cover it with some plywood, seran wrap, and superglue. You can use the little safe as a regular safe. Now go buy a purifier to clean the air in your chamber before you go out. Ohh, and you might want to make sure there is a power outlet in the room, too...

Cheers,

The Dragon

Offline bens

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Re: Lead free solder
« Reply #15 on: June 20, 2008, 12:15:52 AM »
Either get a really big safe, or preferably a steel plated environed room. Buy an environment suit, with breathing. Drill a hole in the steel plating for the breathing tube to go through, tread the tube through, connect it to the breathing machine doohicky, and seal the hole. You can do this with putty, duct tape, hot glue, and aluminum foil (and solder, if you have any ;)). Set up your workbench in the safe/environment room. If you bought the safe, remove the lock. I find a screwdriver works fine. If you need to cover the gaping hole left by the lock, buy a littler, smaller safe and superglue/duct tape/ google the little safe on. If you're broke at this point, cover it with some plywood, seran wrap, and superglue. You can use the little safe as a regular safe. Now go buy a purifier to clean the air in your chamber before you go out. Ohh, and you might want to make sure there is a power outlet in the room, too...

... I just use a soldering iron on my desk ...

Offline emmannuel

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Re: Lead free solder
« Reply #16 on: June 20, 2008, 02:06:35 AM »
Lead tends to cause drain bamage, something I worry about in my line of work :P

Dang... there go my last 6 brain cells  ;)

Offline R.O.B. 2.0

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Re: Lead free solder
« Reply #17 on: June 20, 2008, 10:00:44 AM »
If anyone wants to be really careful, I've read in a few books, set up a small fan in the room where you're working connected to air vent tubing leading outside.

Offline TrickyNekro

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Re: Lead free solder
« Reply #18 on: June 20, 2008, 11:49:39 AM »
Actually I mistakenly forgot my soldering iron on and I was really tired and "accidentally" got a nap...
When I woke up, forget the fire hazard, I felt some pain at both my head and lungs and so on...

But come to this I have been soldering in my bedroom for years with little or no ventilation... some times even for hours...

But I'm still healthy... Involved in sports and so on... no brain damage, no respiratory problems...


Of course overdosing is bad... but gotta overdose a lot....
As far as I know lead can cause a disease cause it can't be disposed off your lungs... in brains I think...

Anyways, welcome to the club...

Lefteris
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline Asellith

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Re: Lead free solder
« Reply #19 on: June 20, 2008, 11:57:17 AM »
One of the guys I work with always uses rubber gloves when he works on anything. I don't think he solders with them on. (bad idea as latex melts to skin easily) But if your really in a bad area and have to do some soldering just get a fume mask not a dusk mask but the kind with the carbon filters that cost like $20. I have one for doing fiberglass work. I don't use it when I solder but I could (to lazy) If you wash your hands after your done you should be ok.
Jonathan Bowen
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Offline Admin

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Re: Lead free solder
« Reply #20 on: June 20, 2008, 12:10:06 PM »
Since we are on the topic of soldering safety, just a reminder to always wear safety goggles. I wear them when soldering, when using snips, and when turning on a circuit for the first time . . . You only have two eyes :o

Offline bens

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Re: Lead free solder
« Reply #21 on: June 20, 2008, 12:30:19 PM »
You only have two eyes :o

Which means it's ok for you to screw up once :D

Offline izua

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Re: Lead free solder
« Reply #22 on: June 20, 2008, 03:59:10 PM »
yeah, but not both of them at once  :P
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Offline Asellith

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Re: Lead free solder
« Reply #23 on: June 20, 2008, 10:40:47 PM »
One of my teachers told a story about how a guy he worked with forgot to change his DMM from current to voltage and shorted across two high voltage bus bars. The DMM exploded embedding shrapnel all in his face. He was wearing goggles and thats the only reason he saved his eyes. Course we never deal with those voltages in robotics. Yet ......
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Offline Rand alThor

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Re: Lead free solder
« Reply #24 on: June 21, 2008, 01:34:02 AM »
Well, after that story, I guess I am glad that my multimeter (that is what you were referring to, right?) shorted out (the fuse blew).

Anyway, on the topic of safe soldering, I had my first soldering...ahem...experience ;) yesterday, I forgot the goggles, but I think I was OK because I did have the garage door and side door open, and I'm glad I thought to bring a big glass of water out in case of emergency because afterwards, I decided to right a book:

A Million and One Stupid Things To do While Trying To Solder
                   (with full color pictures ;))

Number 1:

When trying to desolder a component from a board, apply the iron to the solder and try to pull the component out by the other end with your bare hands.

...

Yeah, I did this, and I still have the marks to prove it. Ha. I can laugh at it now that it doesn't hurt: Imagine my reaction ( :o).
« Last Edit: June 21, 2008, 01:42:46 AM by Rand alThor »

Offline Steel_monkey

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Re: Lead free solder
« Reply #25 on: June 21, 2008, 02:10:54 PM »
If anyone wants to be really careful, I've read in a few books, set up a small fan in the room where you're working connected to air vent tubing leading outside.
If you solder near window that can be opened, this is the simplest solution. Cheapest PC fan + a little paper, and portable ventilation system is ready to use (cost virtually nothing). Only thing it should be close to soldering iron, as close as possible.

Offline Trumpkin

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Re: Lead free solder
« Reply #26 on: June 21, 2008, 05:51:18 PM »
Quote
When trying to desolder a component from a board, apply the iron to the solder and try to pull the component out by the other end with your bare hands.
lol, I have done that before, more than once. I don't learn very quickly  :D.
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Offline Ro-Bot-X

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Re: Lead free solder
« Reply #27 on: June 22, 2008, 06:42:00 AM »
Quote
When trying to desolder a component from a board, apply the iron to the solder and try to pull the component out by the other end with your bare hands.
lol, I have done that before, more than once. I don't learn very quickly  :D.

I used to do that so many times my fingers skin got so thick I didn't even feel any pain, just a hottish temperature. Trying to cool the fingers I used to grab my ear lobe (it absorbs heat fast)... And I was working in a 4'x4' closet with the door closed. The solder was resin filled and it smelled like I was in church or something like that. There wasn't any flux filled solder at the time. I still work with resin today, hate the flux, no splashes, cleans easier, it isolates traces not making a short if you forget to clean it up. When I was in the states I had to ask my brother in Romania to send me some resin since I could not find it there. I will allways work with leaded, resin filled solder. Much better and easier soldering. Oh, and when I solder braided wires, I allways put them in resin first (melting the resin a bit) then apply solder thoroughly so that it goes everywhere between the braids, then connect the wires together or screw them in the terminal block. Heh, and when desoldering something from a board (not a SMD part) I melt the solder, then holding the board tightly with my fingers, I smash it against the table, making sure just the bottom of my hand hits the table. This way the solder flies away and the part comes out easy. Of course, using solder braid makes it easier for your hands, but that doesnt work all the times. And of course I hate the solder sucker, it never works properly. And if you're making your own PCBs, dilute a little resin in alcohol, brush it on the board and then apply a thin layer of solder. Clean the board with alcohol, otherwise it will be sticky. Or do just the pads, clean the board and spray paint it. When you will reheat the pads the paint will crack and go away just over the pads and you'll have a solder mask for the rest of the board...
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