The latest on tin whiskers in lead-free soldering?

[Peter]

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Here in the UK, most people have now moved to lead free solder. A lot
used the Control & Monitoring Equipment ROHS exemption, which is valid
till 2017 and this protects you fine if you sell direct to many small
customers, but if you have big customers you can't use it because most
big firm customers are bullying their supplier base with surveys
demanding a confirmation of total compliance on ROHS & REACH...

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.

But it is in SMT reflow soldering that the whisker troubles happened.
I read the Swatch story; obviously they found a solution eventually.

I wonder if perhaps several factors helped:

1) The silver stabilises the solder and stops whisker forming. I found
most reflow soldering is done with SAC solder, despite its hugely
bigger cost.

2) The industry stopped the quest towards ever finer TSOP package pin
spacing. We use 0.65mm pitch which is probably OK. The really dense
stuff went to BGA which is very well spaced out.

3) Much electronics is consumer stuff and nobody gives a **** if it
packs up after a few years...

The military retain their exemption for ever, presumably for a good
reason.

The problem I have is that out products routinely run for 20 years, in
cabinets, at an elevated temp, perhaps +50C.

Any views?

 

[Joe Gwinn]

In article <ib98v81lubokkq3q5mqvsqsekgj3v8abt6@4ax.com>, Peter
<nospam@nospam9876.com> wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Here in the UK, most people have now moved to lead free solder. A lot
used the Control & Monitoring Equipment ROHS exemption, which is valid
till 2017 and this protects you fine if you sell direct to many small
customers, but if you have big customers you can't use it because most
big firm customers are bullying their supplier base with surveys
demanding a confirmation of total compliance on ROHS & REACH...

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.

But it is in SMT reflow soldering that the whisker troubles happened.
I read the Swatch story; obviously they found a solution eventually.

I wonder if perhaps several factors helped:

1) The silver stabilises the solder and stops whisker forming. I found
most reflow soldering is done with SAC solder, despite its hugely
bigger cost.

2) The industry stopped the quest towards ever finer TSOP package pin
spacing. We use 0.65mm pitch which is probably OK. The really dense
stuff went to BGA which is very well spaced out.

3) Much electronics is consumer stuff and nobody gives a **** if it
packs up after a few years...

The military retain their exemption for ever, presumably for a good
reason.

The problem I have is that out products routinely run for 20 years, in
cabinets, at an elevated temp, perhaps +50C.

Any views?

You need a military product or two.

But even that may not help - it's getting hard to find non-ROHS
components.

Joe Gwinn

 

[John Larkin]

On Sat, 27 Jul 2013 16:50:38 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

In article <ib98v81lubokkq3q5mqvsqsekgj3v8abt6@4ax.com>, Peter
nospam@nospam9876.com> wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Here in the UK, most people have now moved to lead free solder. A lot
used the Control & Monitoring Equipment ROHS exemption, which is valid
till 2017 and this protects you fine if you sell direct to many small
customers, but if you have big customers you can't use it because most
big firm customers are bullying their supplier base with surveys
demanding a confirmation of total compliance on ROHS & REACH...

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.

But it is in SMT reflow soldering that the whisker troubles happened.
I read the Swatch story; obviously they found a solution eventually.

I wonder if perhaps several factors helped:

1) The silver stabilises the solder and stops whisker forming. I found
most reflow soldering is done with SAC solder, despite its hugely
bigger cost.

2) The industry stopped the quest towards ever finer TSOP package pin
spacing. We use 0.65mm pitch which is probably OK. The really dense
stuff went to BGA which is very well spaced out.

3) Much electronics is consumer stuff and nobody gives a **** if it
packs up after a few years...

The military retain their exemption for ever, presumably for a good
reason.

The problem I have is that out products routinely run for 20 years, in
cabinets, at an elevated temp, perhaps +50C.

Any views?

You need a military product or two.

But even that may not help - it's getting hard to find non-ROHS
components.

Joe Gwinn

Lead-free parts solder fine with 63/37 solder. That combination looks
great but probably still has some whisker hazards.

There is debate about temperature profiles when soldering lead-free
BGAs with leaded solder. Some people say you have to melt the balls,
and some think that all you need to do is solder to them, which takes
a lower peak temperature. We've done it both ways and both seem to
work fine.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[Jon Elson]

Peter wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.
I've been using SAC 305 type solder for some time to finish

assembling lead free boards, after they come off the pick and place
machine. Yes, it is a lot more expensive that tin-lead. Mostly,
I end up buying solder on eBay at about half list price. Some
works better than others. The latest wire solder I have gotten is
from Cookson, and it seems to wet and flow better than stuff I've
used before. I normally run my iron at 370C (700F) but with a
really heavy tip on my Weller WMP iron I can solder fine at 343C
(650 F). I have excellent results with this.

Jon

 

[Robert Baer]

Peter wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Here in the UK, most people have now moved to lead free solder. A lot
used the Control& Monitoring Equipment ROHS exemption, which is valid
till 2017 and this protects you fine if you sell direct to many small
customers, but if you have big customers you can't use it because most
big firm customers are bullying their supplier base with surveys
demanding a confirmation of total compliance on ROHS& REACH...

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.

But it is in SMT reflow soldering that the whisker troubles happened.
I read the Swatch story; obviously they found a solution eventually.

I wonder if perhaps several factors helped:

1) The silver stabilises the solder and stops whisker forming. I found
most reflow soldering is done with SAC solder, despite its hugely
bigger cost.

2) The industry stopped the quest towards ever finer TSOP package pin
spacing. We use 0.65mm pitch which is probably OK. The really dense
stuff went to BGA which is very well spaced out.

3) Much electronics is consumer stuff and nobody gives a **** if it
packs up after a few years...

The military retain their exemption for ever, presumably for a good
reason.

The problem I have is that out products routinely run for 20 years, in
* ---------- our -------------^

cabinets, at an elevated temp, perhaps +50C.

Any views?
SAC has a higher MP than Sn96.3Ag3.7, and i understand that it has

soldering problems, some of which you allude to.
Those higher processing temps degrade everything..

The "plain" tin/silver alloy mentioned above seems to flow as easily
as original tin/lead (aka 60/40 or thereabouts) and i have made zero
adjustments to iron temp.
Reflow also works like a charm.

 

[Robert Baer]

Joe Gwinn wrote:

In article<ib98v81lubokkq3q5mqvsqsekgj3v8abt6@4ax.com>, Peter
nospam@nospam9876.com> wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Here in the UK, most people have now moved to lead free solder. A lot
used the Control& Monitoring Equipment ROHS exemption, which is valid
till 2017 and this protects you fine if you sell direct to many small
customers, but if you have big customers you can't use it because most
big firm customers are bullying their supplier base with surveys
demanding a confirmation of total compliance on ROHS& REACH...

At work we tested about 30 hand solders and all but two were absolute
crap. I cannot see who could use the others - except maybe with a
*very* hot iron e.g. 400C+ and zero quality control. The two which
worked both contained silver (SAC solder). One was GBP 45/0.5kg (5x
more than normal solder) and the other, which is actually pretty good,
is GBP 65 (from Almit in Japan). Per product, the cost of the hand
solder is negligible however. Neither of the two flows well; they do
good joints but basically the solders stays where you put it. It
doesn't like to flow into a gap e.g. if soldering a TO220-style
package onto a PCB by the tab on it.

But it is in SMT reflow soldering that the whisker troubles happened.
I read the Swatch story; obviously they found a solution eventually.

I wonder if perhaps several factors helped:

1) The silver stabilises the solder and stops whisker forming. I found
most reflow soldering is done with SAC solder, despite its hugely
bigger cost.

2) The industry stopped the quest towards ever finer TSOP package pin
spacing. We use 0.65mm pitch which is probably OK. The really dense
stuff went to BGA which is very well spaced out.

3) Much electronics is consumer stuff and nobody gives a **** if it
packs up after a few years...

The military retain their exemption for ever, presumably for a good
reason.

The problem I have is that out products routinely run for 20 years, in
cabinets, at an elevated temp, perhaps +50C.

Any views?

You need a military product or two.

But even that may not help - it's getting hard to find non-ROHS
components.

Joe Gwinn
What diff? The arts have so little solder on them that machs nicht.

 

[Jeff Liebermann]

On Sat, 27 Jul 2013 21:12:02 +0100, Peter <nospam@nospam9876.com>
wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Some more current info on tin and zinc whiskers.
<http://nepp.nasa.gov/whisker/>
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[mokhamad khamim]

Ipad Video Lessons - Big Seller! Now 75% Commission!!
84 Million Ipad Sold... With No Ipad Instructions! Works With All Ipad Versions. Updated To Ipad Ios6. Get Your Ipad Video Lessons Affiliate Tools Http://ipadvideolessons.com/affiliates


http://59d8b8bl0gua5js8v6qgnah9wh.hop.clickbank.net/

 

[rickman]

On 7/27/2013 8:40 PM, Jeff Liebermann wrote:

On Sat, 27 Jul 2013 21:12:02 +0100, Peter<nospam@nospam9876.com
wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

I thought the Toyota incident was relatively recent. But looking at the
NASA paper I see the car was a 2005 model. It just took five years to
get the info to NASA... or maybe it took nearly five years for the
whisker to form?

--

Rick

 

[Jeff Liebermann]

On Sat, 27 Jul 2013 22:00:13 -0400, rickman <gnuarm@gmail.com> wrote:

On 7/27/2013 8:40 PM, Jeff Liebermann wrote:
On Sat, 27 Jul 2013 21:12:02 +0100, Peter<nospam@nospam9876.com
wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

I thought the Toyota incident was relatively recent. But looking at the
NASA paper I see the car was a 2005 model. It just took five years to
get the info to NASA... or maybe it took nearly five years for the
whisker to form?

<http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA-GSFC-whisker-failure-app-sensor.pdf>
It was a 2003 Toyota Camry. The incident happened in 2005. The
report was commission by the Dept of Transportation in 2010, and was
completed in 2011. The full report is at:
<http://www.nhtsa.gov/UA>
<http://www.nhtsa.gov/staticfiles/nvs/pdf/NASA-UA_report.pdf>
Looks like any potential difference over 2.6v will form whiskers.
Amazing. See Pg 25.

I have to deal with tin whiskers in older GE MSTR radios, commonly
used in mountain top repeaters. There are various fixes, but the one
we've adopted is to wait until there are signs of sensitivity loss.
Then we drive up to the mountain with an air compressor and service
monitor, tear open the helical resonator assembly, blow out the tin
whiskers with compressed air, and retune the cavities with the service
monitor. It's been every 10 years so it's not a major problem.
<http://www.repeater-builder.com/ge/mastr2/m2casting.html>

Before the ban on leaded solder arrived, I decided to stock up on
63/37 solder for my repair biz. I assumed that there would be a
government inspired crackdown on users and dealers of the dreaded
leaded solder. It didn't happen. So, I now have a lifetime supply of
63/37. However, I don't use leaded solder because it doesn't suffer
from tin whiskers. The problem is that the unleaded solders produce
brittle joints that easily crack under stress or vibration. I've seen
far too many boards with annular rings around the solder connection
where a vibrating or heavy component (e.g. PCB mounted power
transformers) would break the solder connection. Leaded solder will
cold flow slightly and absorb the stresses. Unleaded will crack.
<http://www.discovercircuits.com/dc-mag/Issue_11/Photos/SebDLMCrack.jpg>
<http://ww2.justanswer.com/uploads/TV/TVTech1/2013-04-05_195034_solder_cracks.jpg>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Peter]

Jeff Liebermann <jeffl@cruzio.com> wrote

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

I thought the Toyota incident was relatively recent. But looking at the
NASA paper I see the car was a 2005 model. It just took five years to
get the info to NASA... or maybe it took nearly five years for the
whisker to form?

http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA-GSFC-whisker-failure-app-sensor.pdf
It was a 2003 Toyota Camry. The incident happened in 2005. The
report was commission by the Dept of Transportation in 2010, and was
completed in 2011. The full report is at:
http://www.nhtsa.gov/UA
http://www.nhtsa.gov/staticfiles/nvs/pdf/NASA-UA_report.pdf
Looks like any potential difference over 2.6v will form whiskers.
Amazing. See Pg 25.

This is scary and it seems that nothing has actually changed, and all
that the EU has achieved is to trash long term product life.

I do find this hard to believe...

 

[Peter]

Jeff Liebermann <jeffl@cruzio.com> wrote

Looks like any potential difference over 2.6v will form whiskers.
Amazing. See Pg 25.

The 2.6V is actually the voltage needed to break down the oxide layer
which forms on the whiskers and which stops them shorting things out.

The whiskers form without any power applied to the component(s).

 

[Jan Panteltje]

The problem I have is that out products routinely run for 20 years, in
cabinets, at an elevated temp, perhaps +50C.

Any views?

Yes, lead free is a crime against humanity.
It is designed by clueless politicians and gang-green infected whale hunter hunters.

It is a crime because industry wanted it so it can sell you a new pad every few years,
and now it no longer needs to design in replaceable batteries, as the thing will last shorter than
the batteries anyways.
AND silver solder is poisonous to humans.
And now land fill after landfill fills with pad and mobile phones and pods and whiskers basically.

All my equipment is military luckily so I am exempt.

;-)

 

[Jan Panteltje]

On a sunny day (Sun, 28 Jul 2013 07:41:39 +0100) it happened Peter
<nospam@nospam9876.com> wrote in <j7f9v8h9u3eo54nkh803jfk2flu3qfh08b@4ax.com>:

Jeff Liebermann <jeffl@cruzio.com> wrote

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

I thought the Toyota incident was relatively recent. But looking at the
NASA paper I see the car was a 2005 model. It just took five years to
get the info to NASA... or maybe it took nearly five years for the
whisker to form?

http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA-GSFC-whisker-failure-app-sensor.pdf
It was a 2003 Toyota Camry. The incident happened in 2005. The
report was commission by the Dept of Transportation in 2010, and was
completed in 2011. The full report is at:
http://www.nhtsa.gov/UA
http://www.nhtsa.gov/staticfiles/nvs/pdf/NASA-UA_report.pdf
Looks like any potential difference over 2.6v will form whiskers.
Amazing. See Pg 25.

This is scary and it seems that nothing has actually changed, and all
that the EU has achieved is to trash long term product life.

I do find this hard to believe...

It was the PURPOSE of that rule: produce and sell more.
For the same reason they change TV standards and other standards
ever more often: sales.

 

[Syd Rumpo]

On 28/07/2013 01:40, Jeff Liebermann wrote:

On Sat, 27 Jul 2013 21:12:02 +0100, Peter <nospam@nospam9876.com
wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

It's a bit like the first gulf war when we saw on the TV news a laser
guided bomb blow up a bunker by flying down the ventilation shaft. The
same one, over and over and over again.

Every time this comes up, these same pictures come out. If whiskers
really are such a problem why are there not many hundreds of pictures?

FWIW, I've been using lead-free for many years for other than ROHS
reasons, and once you're used to the difference, it seems easy and reliable.

cheers
--
Syd

 

[Jeff Liebermann]

On Sun, 28 Jul 2013 09:33:53 +0100, Syd Rumpo <usenet@nononono.co.uk>
wrote:

On 28/07/2013 01:40, Jeff Liebermann wrote:
On Sat, 27 Jul 2013 21:12:02 +0100, Peter <nospam@nospam9876.com
wrote:

A lot was said about this c. 2005 but the whole discussion seems to
have died down.

Some more current info on tin and zinc whiskers.
http://nepp.nasa.gov/whisker/

It's a bit like the first gulf war when we saw on the TV news a laser
guided bomb blow up a bunker by flying down the ventilation shaft. The
same one, over and over and over again.

Every time this comes up, these same pictures come out. If whiskers
really are such a problem why are there not many hundreds of pictures?

Absence of evidence is not evidence of absence. Tin whiskers is not
something that the general public would find entertaining. Same with
bulging electrolytic capacitors. That's a known major problem, yet
few people outside of the industry even know that it's happening. It's
much the same with tin whiskers. Once you're outside of the
electronics community, nobody knows or cares about it.

In my personal experience, I've had to deal with tin whisker problems
in 2-way radios on helical resonator cans and on square stake pin
connectors. I've also seen various problems that magically
disappeared after I brushed the boards, which were probably tin
whiskers. It's far from epidemic, but certainly present.

However, if it's photos and horror stories that you want:
<https://www.google.com/search?tbm=isch&q=tin+whiskers>
<http://blekko.com/#?q=tin%20whiskers&images=1>
<http://nepp.nasa.gov/whisker/anecdote/>
<http://nepp.nasa.gov/whisker/photos/>

FWIW, I've been using lead-free for many years for other than ROHS
reasons, and once you're used to the difference, it seems easy and reliable.

Enlighten me please. Why would you want to use RoHS solder other than
for ecological reasons? I can possibly see it if you are using very
dense PCB traces, because the non-wetting properties of RoHS solders
will reduce bridging. What other benefits did I miss?


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Peter]

Syd Rumpo <usenet@nononono.co.uk> wrote

Every time this comes up, these same pictures come out. If whiskers
really are such a problem why are there not many hundreds of pictures?

Googling suggests that the issue of whiskers shorting out component
*leads* may have been solved by using some gold palladium etc plating
on them. Maxim suggests that this may be standard on their chips so I
guess others have done something similar.

What is a worry is that, immediately post the ROHS shafting of
electronic manufacturing back c. 2005, a lot of chips went to tin-only
plating on the leads, and this WILL grow whiskers. They grow up to 1mm
per year. They grow rapidly in vacuum which is why this has been a
huge issue in space and high altitude (unpressurised) applications.

But I see nothing having obviously changed on whiskers growing out of
lead-free solder *joints*. There is a suggestion that SAC (silver
loaded) solder suffers less from whiskers, but it's only a degree,
nowhere near an elimination.

There is one conformal coating, Arathane 5750, which stops whiskers
growing. It is very expensive (though probably insignificant on a
per-PCB basis), very hard to get here in the UK, but most importantly
conformal coatings are very expensive to apply. I have used them for
many years, and they are a pain in the ****. You have to let the PCBs
dry off, etc. We use CC on PCBs which have little toroidal
transformers as it helps secure the windings in place. But it cannot
be used on PCBs that have connectors, or mounting holes through which
you are expecting earthing continuity, etc, unless you do fancy
masking.

My guess is that anybody using pure-tin-plated chips ought to stick
some Arathane 5750 onto the pins, at least. A quick spray through a
template would do it.

Researching this leads to a really sh*t realisation that the EU has
shafted all of us, and the big corporations (with the US ones behaving
in the most disgusting manner when it comes to screwing suppliers)
having a big play in it...

 

[Phil Allison]

"Jeff Liebermann = lying radio ham cunthead "

Absence of evidence is not evidence of absence.

** Yes it FUCKING is - you brainless, bullshitting TWAT !!

1. Whenever the evidence SHOULD be there and is NOT.

2. When there is simply no proper supporting evidence at all.

FYI:

The NUMBER ONE proof that something is 100% BULLSHIT

- is that nothing *credible* makes it fact.

Idiot.



.... Phil

 

[Syd Rumpo]

On 28/07/2013 09:59, Jeff Liebermann wrote:

<snip>

Enlighten me please. Why would you want to use RoHS solder other than
for ecological reasons? I can possibly see it if you are using very
dense PCB traces, because the non-wetting properties of RoHS solders
will reduce bridging. What other benefits did I miss?

Higher softening and melting point for high temperature work. ROHS
actually made things better in that regard as the Sn/Pb solder on
component pins would often need to be removed before use. It doesn't
take much Pb contamination to lower the melting point and weaken the
solder joint, particularly with the small amount of solder used with
surface mount.

Sometimes Sn/Pb solder is used to deliberately contaminate a joint to
aid component removal. This solder is kept in a locked cabinet.

I've never seen a tin whisker in real life, and have spent many an hour
looking at solder joints through a microscope.

Cheers
--
Syd

 

[Jan Panteltje]

On a sunny day (Sun, 28 Jul 2013 12:17:03 +0100) it happened Syd Rumpo
<usenet@nononono.co.uk> wrote in <kt2u7f$s2i$1@dont-email.me>:

You may not have noticed them,
AF118 was a common failure in TV vidicon cameras input stage:
http://nepp.nasa.gov/whisker/anecdote/af114-transistor/index.html

Scares me!