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

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

#71

Post by deathanatos »

at_a_remove wrote: post #47
xmodem wrote: post #33

Earlier quoted context omitted.

The boiling point of water is 100 °C, and yet my shower seems to produce an awful lot of steam despite not being anywhere close to that.

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. Does that translate to lead: i.e., even if I'm below lead's boiling point, could I be nonetheless breathing in lead vapor, or something like that? (I don't know the answer here, which would push me towards lead-free solder. I.e., I don't know if the precautions I'd take with lead would actually suffice.)

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

#72

Post by myself248 »

Flozzin wrote: post #10
dmitrygr wrote: post #4

Use lead solder, like NASA does: easier to use, and no whisker issues. Just wash your hands afterwards

I wouldn't recommend this. If you do use lead soldering, make sure you don't breathe in any fumes.

Or just get your blood lead level measured.

A few months ago, I happened to be at the doctor getting some other stuff checked out, and the week prior to the appointment I had done a ton of soldering, like two 12-hour days bashing out a whole batch of boards, both paste reflow and hand-PTH work, with a fair bit of sucker rework, and of course after that the lab needed a good tidying so I emptied all the suckers and tip cleaners as part of that. All tin-lead solder.

Zero gloves, and I only wore a mask part of the first day (when there were other people around). And actually the several weeks leading up to that also saw a lot of SMT rework and other up-to-by-elbows-in-solder sort of activity.

So I figured, that's kind of a worst-case for my lead exposure, hey Doc, can I get my blood lead level checked? Sure why not, it's one extra vial on top of the bloodwork already being ordered!

And the results came back below the test's detectable level.

So as far as I'm concerned, if that didn't do it, I don't think I have anything to worry about. Now, I'm sort of a germophobe and I never eat with my hands, so this doesn't necessarily generalize, but as far as skin absorption or vapor inhalation, I've gone from "not very worried" to "abjectly unconcerned" after getting that result.

I would encourage everyone to get their level measured and have actual data to make decisions with. Superstition does not become us.

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

#73

Post by JaggedNZ »

Steltek wrote: post #23
dmitrygr wrote: post #4

Use lead solder, like NASA does: easier to use, and no whisker issues. Just wash your hands afterwards

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.

Fellow hobbyist here. Actually your biggest health risk is industrial asthma from flux fumes. I know professionals who have spent a good fraction of there lives soldering with no lead poisoning issues. Lead needs to be consumed or inhaled for it to be an issue. The guy I meet who did have lead poisoning, large bore rifle shooting coach, from spending to much time at the “wrong end” of the rifle range. Lots of lead dust there.

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

#74

Post by hulitu »

alfor wrote: post #69
robomartin wrote: post #9

I have dealt with the tin whisker problem in the context of aerospace applications (both space-borne and terrestrial flight), including extensive consulting with subject matter experts from NASA. The bottom line is quite simple: Tin whisker growth onset is a stochastic process. We cannot predict when it will start and we cannot prevent it. Once they start growing it is almost impossible to contain them. They will pok…

Does wisker form inside semiconductor also or do they use metals immune to that?

Yes they do but slower. In the past gold was used for wires from terminal to pads. Gold as far as i know is not so subceptible to form whiskers. But gold is expensive and now they use copper instead of gold.

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

#75

Post by hulitu »

xmodem wrote: post #38
robomartin wrote: post #9

I have dealt with the tin whisker problem in the context of aerospace applications (both space-borne and terrestrial flight), including extensive consulting with subject matter experts from NASA. The bottom line is quite simple: Tin whisker growth onset is a stochastic process. We cannot predict when it will start and we cannot prevent it. Once they start growing it is almost impossible to contain them. They will pok…

Do you happen to know if tin whiskers have anything to do with passing current? (in other words, will a device that's in constant use develop them faster than a physically identical device that's switched off and in storage)

Yes. Voltage has a big effect on whiskers.

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

#77

Post by hulitu »

zozbot234 wrote: post #54
adrian_b wrote: post #50

Earlier quoted context omitted.

The sky is not falling in large part because the transition to lead-free solder was simultaneous with the transition to electronic devices that are not repaired and which frequently have a lifetime not much longer than their warranty time. Most current electronic devices are dumped much earlier than when they would fail due to the tin whiskers. Many consumer electronic devices made 50 years ago are still usable witho…

Consumer electronics used to break down all the time 50 years ago. Metal whiskers are not even close to being relevant when other factors impact reliability and durability to a far greater extent.

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.

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

#78

Post by walrus01 »

Damogran6 wrote: post #31

State of Colorado Datacenters got them. The response to them were weird...if any machine were in any of the affected areas, they were persona non grata...they could never leave those datacenters as functional server. It DID lever some money for an awesome off-site backup datacenter...which was eventually our only datacenter for 'reasons'. In our case, I think one of the datacenter's raised floors got carpeted (don't…

raised floors in general are a nightmare for grounding/bonding/differences in potential between racks, the steel floor structure, the building, and electrical conduits.

there's a reason why almost nobody builds them new from a clean-sheet-of-paper design anymore for serious datacenter applications or ISP/telecom purposes, which are racks/cabinet on concrete slab and everything overhead now.

it's much easier to ground/bond everything together using some very fat copper cables run along ladder rack overhead, and bond all the racks to that.

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

#79

Post by hulitu »

_Microft wrote: post #48
MisterTea wrote: post #32

Earlier quoted context omitted.

Yes but the parent is not stating that. They are stating that a "save the environment" effort is not very environmentally friendly if it makes more waste.

They are assuming that these devices would be used long enough for tin whiskers to become a problem. I seriously doubt that RoHS will be causing more waste - because at the point that devices become unusuable, they are on in the trash anyways for completely unrelated reasons (think: bezel to large to be popular, plastic backshell instead of metal or glass, device is too thick, device is too heavy, ...).

Tin whiskers continue to grow even after you device is in the landfill. You basically have a dust of tin which goes into landfil.

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

#80

Post by hulitu »

nomel wrote: post #51
MisterTea wrote: post #32

Earlier quoted context omitted.

Yes but the parent is not stating that. They are stating that a "save the environment" effort is not very environmentally friendly if it makes more waste.

That assumes waste reduction is the goal, rather than lead reduction. With toxic, intelligence reducing [1], materials like lead, maybe some extra waste is a perfectly good trade off. 1. https://news.ycombinator.com/item?id=30600539

Last i checked tin was not an edible material. There is a small difference between having tin dust, which you cannot contain, and having electronics containing lead which you can colect and store in a warehouse ( asuming you want to address the problem in the first place).
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