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Tin whiskers: What happens when they spontaneously erupt? (2018)

microcontrollertips.com

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Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#121

Post by adrian_b »

hulitu wrote: post #89
adrian_b wrote: post #41

Earlier quoted context omitted.

It is extremely unlikely to ever find any solution to the tin whiskers problem, other than alloying tin with toxic elements, i.e. either lead or antimony. The reliability problem could be solved only by replacing soldering with another method of making electrical connections during PCB assembly, e.g. thermal/ultrasonic welding of copper on copper, metal deposition in vacuum etc. While replacing soldering is possible,…

> The reliability problem could be solved only by replacing soldering with another method of making electrical connections during PCB assembly, e.g. thermal/ultrasonic welding of copper on copper, metal deposition in vacuum etc. The whiskers are not related to soldering. Of course there are some soldering issues which facilitate whiskers but that's about it. Tin is a normal plating material so you can find whiskets i…

The whiskers are related to tin.

The only reason for using tin is soldering. Tin is used because it is the only metal with the right melting temperature, neither too low nor too high.

When you do not use soldering, you do not need tin. While it is possible for whiskers to also form on other metals, the chances of this happening are negligible in comparison with tin.

So yes, the only reason for whiskers being a serious problem is the need to use soldering.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#122

Post by squarefoot »

oceanplexian wrote: post #84
squarefoot wrote: post #66

Earlier quoted context omitted.

> Consumer electronics used to break down all the time 50 years ago But they could be easily repaired.

Once things started going to multi-layer PCBs it was the end of reparability. It’s too bad because I have fond memories of fixing broken components on PC hardware and game consoles, even as someone who’s not an expert and simply a hobbyist.

> Once things started going to multi-layer PCBs it was the end of reparability.

Very true, however having full documentation would help nonetheless. My water heater electronic board cost over €250 to replace, although it contains less than €20 parts; a preprogrammed uC makes it impossible to replicate it. If it had public hardware and firmware documentation, someone could repurpose a similar but cheaper board or replicate the functions using a different rugged enough uC board, which would also likely bring down the retail price of the original spare part.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#123

Post by foldr »

CamperBob2 wrote: post #117
mrob wrote: post #88

Earlier quoted context omitted.

Agreed. This, not lead fumes, is the real danger of leaded solder. You can't hand solder reliably without cleaning the iron, but both of the common cleaning techniques (damp sponge and brass wool) inevitably break the soldier into tiny balls, which bounce and roll all over the place. They can get caught in clothes, and from there they might end up getting into food. With the safe dose for lead being zero, I don't thi…

Bioavailability of metallic lead is practically nil.

Eating lead is the worst case scenario when it comes to lead poisoning. Yes, your body will manage not to absorb much of the lead. But you can't seriously be suggesting that lead is safe to eat!

I'm not sure if maybe you were misinterpreting 'end up in food' in the post you're replying to. The GP isn't talking about the lead getting into the soil and then indirectly into the food supply. They're talking about the scenario where some little balls of solder are literally inside the sandwich you're eating.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#124

Post by throwaway0a5e »

alar44 wrote: post #95
Steltek wrote: post #23

Earlier quoted context omitted.

On the contrary, I am not NASA. I'm not even a consumer electronics company. I'm a hobbyist at home, soldering things at my desk or table. Lead-free is the least of my problems when building something and I don't believe "just wash your hands" is sufficient for cleaning my workspace (or kitchen table?) of possible lead contamination.

It definitely is enough. I don't know where the myth that looking at lead kills you started, but unless you are eating it or breathing it in (soldering is not hot enough to vaporize lead) there's nothing to worry about.

>I don't know where the myth that looking at lead kills you started

For a large subset of western society it's highly fashionable to give a lot of shits about health and safety. I'm not saying this is a bad thing to care about but let's be honest here, when you treat abstract concepts like a minor religious deity there's some baggage that comes with that. Let the feedback loops run their course for a decade or three and combine that with the fact that it's very easy to be scared of things you're not familiar with and you get the current situation. This is why people go crazy over a long forgotten package of asbestos shingles sitting on some shelf in the maintenance department's storeroom or think you're gonna get black lung from using an antique coal stove a couple times a year. Their belief system tells them to go crazy and they don't have the experience to know they don't need to.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#125

Post by detaro »

atesti wrote: post #99

Does anybody from Germany know where I can still buy leaded solder? Unfortunately I forgot to order a lifetime supply while it was still available

It's trivial to find online shops selling it, even if the large hobby-electronics suppliers have generally stopped stocking it. RS, TME, eleshop, ... all have it.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#126

Post by hulitu »

olyjohn wrote: post #120
hulitu wrote: post #77

Earlier quoted context omitted.

They used to break down and they could and were repaired. Nowadays if something breaks it goes in the garbage can. I had an extension cable which died staying in the basement for a year. When i opened it to check the reason i was shocked. It looked like a spider net made of dust but this was metal.

> When i opened it to check the reason i was shocked. Sounds like you should unplug it before you open it up.

It was not working. I opened it to check why.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#127

Post by hulitu »

adrian_b wrote: post #121
hulitu wrote: post #89

Earlier quoted context omitted.

> The reliability problem could be solved only by replacing soldering with another method of making electrical connections during PCB assembly, e.g. thermal/ultrasonic welding of copper on copper, metal deposition in vacuum etc. The whiskers are not related to soldering. Of course there are some soldering issues which facilitate whiskers but that's about it. Tin is a normal plating material so you can find whiskets i…

The whiskers are related to tin. The only reason for using tin is soldering. Tin is used because it is the only metal with the right melting temperature, neither too low nor too high. When you do not use soldering, you do not need tin. While it is possible for whiskers to also form on other metals, the chances of this happening are negligible in comparison with tin. So yes, the only reason for whiskers being a seriou…

There are tin plated connectors.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#128

Post by at_a_remove »

deathanatos wrote: post #71
at_a_remove wrote: post #47

Earlier quoted context omitted.

You have confused steam with small water droplets, akin to what emerges from an ultrasonic mister. If it were steam, you would be shrieking and then dead.

But it's still water, and it's still moving up and about of its own accord in the local air which is the point. That it isn't technically steam doesn't disprove the point the person you're responding to is trying to make… The commenter's point isn't that the lead has technically been boiled, it's that, if we analogize to "steam" in a shower, I don't have to reach water's boiling point before I'm breathing in water. D…

That's the reason I was being persnickety and "science-y" about terms: analogies can lead you astray. You don't know the answer here, and so your options are: 1) do some experiments, 2) reason by science, not analogy.

I have some weightlifting plates. Pure iron. Can I forego iron in my diet and just ... sit next to them? Now, by analogy, sure. Practically? Probably not.

Here's one for you: what do you think happens if you drank a glass of pure liquid mercury?

Most people think you'd die on the spot. Wrong! That mercury hasn't sublimated into mercury vapor. Instead, it barrels through your alimentary canal like a shot and was used to treat constipation, of all things. It is poorly absorbed by digestion and just runs right through you.

Phase changes matter for these things.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#129

Post by orisho »

olyjohn wrote: post #120
hulitu wrote: post #77

Earlier quoted context omitted.

They used to break down and they could and were repaired. Nowadays if something breaks it goes in the garbage can. I had an extension cable which died staying in the basement for a year. When i opened it to check the reason i was shocked. It looked like a spider net made of dust but this was metal.

> When i opened it to check the reason i was shocked. Sounds like you should unplug it before you open it up.

Funny!

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#130

Post by CamperBob2 »

foldr wrote: post #123
CamperBob2 wrote: post #117

Earlier quoted context omitted.

Bioavailability of metallic lead is practically nil.

Eating lead is the worst case scenario when it comes to lead poisoning. Yes, your body will manage not to absorb much of the lead. But you can't seriously be suggesting that lead is safe to eat! I'm not sure if maybe you were misinterpreting 'end up in food' in the post you're replying to. The GP isn't talking about the lead getting into the soil and then indirectly into the food supply. They're talking about the sce…

I don't know anyone who would recommend eating while working with lead solder. At some point, common sense has to come into play.

Fortunately, common sense is enough. Metallic lead simply isn't that toxic in the grand scheme of things.

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