# Tin Whiskers and RoHS



## Don Doucette (Jan 3, 2007)

First off Check out these links;

http://nepp.nasa.gov/whisker/
http://nepp.nasa.gov/whisker/failures/
http://nepp.nasa.gov/whisker/anecdote/index.html

Have any of you folks given any thought about the built in obsolescence that RoHS is going to cause to all electronics? I have made a concious effort in the past few years to only purchase non RoHS compliant equipment but it is getting hard to find non compliant equipment. I have also been stocking up on solder so that I don't run into grief down the road when repairing vintage electronics.

Nasa, the US military and most manufacturers of life support equipment are RoHS exempt for the time being, sudden catastrophic failures attributed to Tin Whiskers is not what you want to happen in these areas of industry but what about the general public whos dollar drives the economy, why must we suffer losses due to early failures, don't get me wrong I am all for sound environmental causes but not when it has such an adverse effect on the things I buy and use everyday.

What are your thoughts?

Don:smilie_flagge17:


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## J S Moore (Feb 18, 2006)

I am going out to stock up on solder. I don't like the un-leaded version. Doesn't flow properly and it's too hard to get a good solder joint.


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## bagpipe (Sep 19, 2006)

Can you give a brief rundown for those of us too lazy to read through the links? I guess they're now pushing non-leaded solder on everyone? Which can cause problems because the solder doesn't flow so well?


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## Rugburn (Jan 14, 2009)

I took a soldering course last fall at college and we discussed this quite a bit. Our professor has been working as an electrical engineer for over 40 years, and his feelings were that un-leaded solder was vastly inferior to work with and was already showing up in some European electronics. In another forum there was a lot of talk about how it would affect old tube amps. I've got some 63/37 or eutetic solder around and it's the best to work with. Leaded solder's minimum heat requirement for reaching it's initial melting point is 361F compared to 421F for L-F solder. This may seem slight, and it is, but it's the flow that's at issue. The thinner the IMZ (Intermetalic Compound Zone) is the better the connection. Because of surface friction inherent with L-F solder wetting is a PITA and may cause weaker connections. "Tin whiskering" is something that could be disastrous in high-voltage circuitry, not to mention sensitive circuits on a plane or space craft.

Shawn.


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## scottomy (Sep 20, 2006)

I'm guilty of being too lazy to read the links. I have been a buyer in electronics (telecom actually) for about 7 years and been building and wiring electronic equipment for 20+ years and I deal with RoHS compliance everyday. I haven't really noticed any problems so far. It does require you adapt your technique to match the new materials used. This means higher soldering temps and the use of flux to aid in the proper flow of solder. 

The position of my company regarding whiskers is somewhat confusing because the thought is, if it is tin over nickel underlay - it's OK. We are technically exempt from the RoHS requirements since we supply telecom infrastructure equipment which is under review for 10 years after the July 2006 cut-off to determine the effects of the process and material changes.

Availability of components has not been a problem but pricing has changed slightly for parts...especially for raw PCB's since the finish has changed from basically solder to gold.


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## Don Doucette (Jan 3, 2007)

Well as it turns out gold is not immune to the whisker phenomenon, so here is another link

You should really take some time to familiarize yourself with this material as it will eventually effect every user of consumer electronics.

Don:smilie_flagge17:


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## Robert1950 (Jan 21, 2006)

Dyuuuuuuuuuhhhhhhh! This is beyond me, almost. Let me reduce this to grade school level. Is this about non-lead solder leading to inferior connections in electrical components and more failures than old time so-called-toxic lead solder????


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## Rugburn (Jan 14, 2009)

Robert1950 said:


> Dyuuuuuuuuuhhhhhhh! This is beyond me, almost. Let me reduce this to grade school level. Is this about non-lead solder leading to inferior connections in electrical components and more failures than old time so-called-toxic lead solder????


Idealy when we solder something we want instant melting and setting. Leaded solder is roughly 60% tin 40% lead. Lead free solder is 96.5% tin 3% silver and 0.5% copper or SAC-305. When soldering there is a period where it is niether solid or liquid, and is referred to as plastic. In 63/37 solder this is very brief (1 second or less). Lead free solder stays plastic longer increasing the likelyhood of a bad connection. It is in this plastic state that movement and strong vibrations can affect the quality of the solder joint. Perhaps less of a concern when working on large components with large leads by hand, but a real issue for mass production and surface mount technology.

Shawn :smile:


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## Don Doucette (Jan 3, 2007)

Robert1950 said:


> Dyuuuuuuuuuhhhhhhh! This is beyond me, almost. Let me reduce this to grade school level. Is this about non-lead solder leading to inferior connections in electrical components and more failures than old time so-called-toxic lead solder????


Also after the component or equipment is manufactured/put into service, whiskers begin to grow from the tin (looking much like stalagmites) and risk causing short circuits leading to failures. The picture below from the nepp.nasa.gov web site shows whiskers growing within a hermetically sealed relay, not so bad after 14 years but think about the scale, now think about the clearance between conductors inside transistors or ICs for that matter and the magnitude of the situation becomes apparent.










_*Pure Tin-Plated Iron Armature Used as Part of the INTERNAL Construction of a Hermetically Sealed Electromagnetic Relay.
Relay is ~14 Years Old. Photo was taken After Removal of the External Case of this Device which then Revealed Extensive Growths of Tin Whiskers with the Longer Whiskers Approaching 3 mm in Length. These Whiskers are More than Long Enough to Cause Electrical Shorts Inside of this Device.*_

The following example is even more convincing...










Don:smilie_flagge17:


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## Geek (Jun 5, 2007)

Terrible idea. I've tried both and lead free is just bad karma for HV circuitry.

Cheers!


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## Don Doucette (Jan 3, 2007)

Eeeek I can just imagine.

Don:smilie_flagge17:


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## Michelle (Aug 21, 2006)

The source has their leaded solder on clearance, or at least here they do. I bought the RadioShack stuff at the liquidators for about 50c/lb.


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## Don Doucette (Jan 3, 2007)

Michelle said:


> The source has their leaded solder on clearance, or at least here they do. I bought the RadioShack stuff at the liquidators for about 50c/lb.


Hmmm I don't usually venture into the source but I will for cheap solder.
Thanks for the tip!

Don:smilie_flagge17:


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## Guest (Jun 30, 2011)

I can't vote. None of the answers work.

I don't like RoHS compliant solder. But I don't think it's a _poor_ solution to lead in landfill sites.


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## Jeff B. (Feb 20, 2010)

RoHS has it's place, which is in the high turnover rate of consumer electronics that people use and then dispose of after a couple of years. If the whiskers take a long time to grow then the odds of a piece of consumer equipment still being used isn't all that great. On the other hand it can cause long term problems in the future in equipment that people constantly use and pass on to others resell etc. such as pedals, guitars, amps and other collectable electronics. These items seldom end up in landfills as they hold value and people keep them. Whiskers would be inevitable in this case.
I prefer the 63/37 leaded but don't find the RoHS stuff that hard to use.


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## urko99 (Mar 30, 2009)

I don't like lead in landfills either, However, Collective community efforts should be stepped up on recycling used electronics instead of dumping in landfills. No wonder our standard appliances and electronics in our homes are failing sooner than they used to. Manufacturers are reaping the benefits of shorter appliance/electronic lifespans which increases profits for them. This sure gives true meaning to "They don't build em like they used to"!


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## keeperofthegood (Apr 30, 2008)

ahhh ELECTROSTATIC TORNADOES! Gotta love em  they are so pretty!!

They also form fast, and under the right conditions you can watch them grow. Total electrical hazard though, but what an amazing thing is surface electrostatic domains.


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## mhammer (Nov 30, 2007)

I'm with Ian. If you ARE going to clutter landfill sites with e-waste, better that it be lead-free. On the other hand, maybe it's just better to make products worth hanging onto for decades, and not be in such a frenzy to keep replacing technology with latest and greatest. And just maybe, it would be nice to actually repair things once in a while, rather than leave them at the end of the driveway. THAT would keep the lead out of the landfill nicely.


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## Milkman (Feb 2, 2006)

Say this could be the beginnings of a New Weird Al song.


Tin Whiskers and R O H S
Those buggers took all our lead
My solder joints all are failing
My pedal board's going dead
(sung to the tune of Neil Young's "Ohio")


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## mhammer (Nov 30, 2007)

Daddy like!:sSig_cool2:

Whether more than 40 people world-wide would get it, is a whole other question. But I know *I'd* laugh enough for at least 50 people.


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## Milkman (Feb 2, 2006)

I worry about you Hammer.


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## mhammer (Nov 30, 2007)

Hehe, you and many others.


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## bluzfish (Mar 12, 2011)

Whatever the solution, ten years from now they will probably find that it causes cancer.


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