"Meat Plow" wrote in message
...
On Sat, 23 May 2009 02:01:09 +0100, "Arfa Daily"
wrote:


"Meat Plow" wrote in message
...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
wrote:


"Eeyore" wrote in message
...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the
IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not
enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant ****s. Why do they think lead was used
in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff
...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day :-)

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match -
almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa


Last I bought was for copper plumbing. I tried the lead free crap and
it was laughable on 1/2 inch water pipe. I have many years experience
soldering and brazing but won't touch the lead free crap again.

I have an acquaintance who is a plumber, and some long time ago when the
stuff was first becoming mandated for electronic construction work, which
was actually some time after it became so for live water systems, I asked
him how he got on with it. He told me that at first they had a lot of
problems getting it to 'stick' to a joint, and problems with leaks. He said
that they had eventually got used to it, and that they could now make joints
as good as with leaded solder. However, he said that it required rather
different techniques to those conventionally used for plumbing soldering in
that the surfaces to be joined must be *very* clean as opposed to just
fundamentally clean, and that an aggressive flux helped. He also said that
it was funny stuff to work with in that it reached its melting point very
suddenly, and then had a tendency to run out of the joint, before re-setting
very suddenly also, so no 'pasty' phase, which I guess would knock on the
head the old technique of 'wiping' a joint. Given that copper expands very
readily, it will be interesting to see if joints start breaking and leaking
in 15 years' time due to the total lack of ductility that lead-free has.
We've all seen the effects of rather more intense thermal cycling on the
short-term integrity of electronic joints. Perhaps plumbing joints are a
ticking timebomb ... :-)


To N.Cook The place that I got my research material from was Tin Technology
Ltd with a website of www.lead-free.org The person that I spoke to at that
body, pointed me to www.dti.gov.uk/sustainability/weee/index.htm I also
spoke to a Dr Goodman at ERAT Technology Ltd

All of this was 3 years ago now, and I have not visited those sites since,
if they still exist, but they did contain some good stuff at the time, and
they might lead you where you want to go, now.

Arfa

Arfa