So what's the truth about lead-free solder ? - Page 12

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Re: So what's the truth about lead-free solder ?


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It's good to hear at last from someone involved in the avionics industry,
and it's also good to hear that this particular industry is identifying
serious problems with the technology, as that might at least help to
maintain their exemption for some years to come. I really hope that the
industry has sufficient strength to stand up to this legislation, and to
continue to maintain their position of refusing to use it on safety /
reliability grounds. With my daily dealings with lead-free solder, and all
of the problems that it has brought to consumer electronics, the thought of
being held seven miles up in the sky by equipment using the same technology,
is truly worrying to me.

I cannot agree more that this whole thing is a poorly thought through
example of 'bandwagon politics' and job justification.

I would be interested in hearing any other input that you may have on the
subject, with regard to the avionics industry. Both anecdotal and factual
would be welcome, and I am sure that Graham (who started this thread) would
like see more from you, as well.

Arfa



Re: So what's the truth about lead-free solder ?



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Can you please detonate yourself in that case ?

Graham


Re: So what's the truth about lead-free solder ?
On Fri, 27 Jul 2007 03:42:53 +0100, Eeyore

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 Fuck off, troll.

Re: So what's the truth about lead-free solder ?



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Tin whiskers will grow through conformal coatings.

Graham


Re: So what's the truth about lead-free solder ?
On Fri, 27 Jul 2007 22:22:16 +0100, Eeyore

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This dude has real problems along those lines:
http://tinyurl.com/27xc98


Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
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Re: So what's the truth about lead-free solder ?
On Fri, 27 Jul 2007 17:29:42 -0400, Spehro Pefhany

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 The silver paint damn near killed Buddy Ebsen.

Re: So what's the truth about lead-free solder ?
On Fri, 27 Jul 2007 22:22:16 +0100, Eeyore

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  That is why I said transformer varnish, and said vacuum impregnated,
not some lame, SOFT conformal coat, WHICH GETS SPRAYED ON.

 The varnish is a much tougher, harder media.  The whisker growth is
slowed by the lack of elements which promote it in bare PCB environs.

 If it hasn't been tried yet, I would state that it would likely work,
and yes, I was ALREADY aware that Tin still has problems with standard
coatings.

Re: So what's the truth about lead-free solder ?

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Sorry, I wasn't concentrating and I thought you were still talking about the
bureaucrats, I thought that would be a very effective solution.

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Oh.. well can we still do the bureaucrats afterwards? ??

Chris

Re: So what's the truth about lead-free solder ?

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Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site).  Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm


--
Joe Chisolm
Marble Falls, TX


Re: So what's the truth about lead-free solder ?
On a sunny day (Wed, 25 Jul 2007 12:29:00 -0500) it happened Joe Chisolm


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Well seems [all] we have to [do is] make some traces .65mm apart :-)

Re: So what's the truth about lead-free solder ?



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Some ? ALL !

Goodbye microelectronics.

I just came across this too.
http://en.wikipedia.org/wiki/Tin_pest

" At 13.2 degrees Celsius (about 56 degrees Fahrenheit) and below, pure tin
transforms from the (silvery, ductile) allotrope of beta-modification white tin
to brittle, alpha-modification grey tin. Eventually it decomposes into powder,
hence the name tin pest."


Graham



Re: So what's the truth about lead-free solder ?
On Wed, 25 Jul 2007 19:03:35 +0100, Eeyore

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AFAIK this exemption only applies to component lead finishes.

Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
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Re: So what's the truth about lead-free solder ?
On a sunny day (Wed, 25 Jul 2007 14:47:25 -0400) it happened Spehro Pefhany

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Too bad....
How about conductive glue replacing solder?
Na, will have to wait until the first EU politician's cellphone fails in
some emergency.
 

Re: So what's the truth about lead-free solder ?

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What ever happened to 'multiwire' (or some such trade name)? It was
a multilayered weld-bonded wiring alternative to multilayer PCBs
in the '60s and '70s and was very rugged, easily implemented with
NC technology, and used no solder of course.

Since each layer is built up in succession, between power and ground
planes, even BGAs can be accomodated.

Regards,

Michael

Re: So what's the truth about lead-free solder ?



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Gone the same way as wire wrap it seems.

Graham


Re: So what's the truth about lead-free solder ?
On Wed, 25 Jul 2007 21:56:53 +0100, Eeyore

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  Most VME backplanes utilize a press fit pin, directly into a clad hole,
and it is gas tight in the connection regions and there is no solder
involved.  Lasts for years and years.

Re: So what's the truth about lead-free solder ?
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You just named the problem with Multiwire--wire is sequentially
applied
to a thermoplastic substrate.

Whatever other advantages or problems it may have, it is a
*prototyping*
process, not a mass production process.  It is to PCB production as
e-beam is to photolithography.


Re: So what's the truth about lead-free solder ?
On a sunny day (Wed, 25 Jul 2007 15:48:39 -0500) it happened msg

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Never heard of it, sound OK though.

Re: So what's the truth about lead-free solder ?



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How about getting a clue ? You can get conductive epoxy adhesive btw. It's
loaded with silver particles and is ridiculously expensive.

Graham


Re: So what's the truth about lead-free solder ?
On Wed, 25 Jul 2007 19:26:58 GMT, Jan Panteltje

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 There have been polymer based conductive circuit assembly adhesives
around for several years now.

 NOT cheap.

  The answer will be Rhodium alloy solders for safety and mission
critical applications... perhaps.

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