"Leonard Caillouet" wrote in message
...

"Arfa Daily" wrote in message
...
A number of independant metalurgical experts are of the opinion that by
mixing the two solders, the long term integrity of the joint will be
compromised.

Who are these experts and where are the links to the info on this? I
would be curious what testing they have done and on what formulations.
The vendors that have been willing to comment to me off the record say
that there is no problem and that they are just political CYAing when they
say to use lead free to repair lead free boards.

Leonard

Hi Leonard

I came across several on the net saying much the same thing, when I was
researching an article on the stuff a couple of years back, when everyone in
the business thought that it was suddenly going to be "illegal" to use
leaded solder after the RoHS directive came in, and that if you did, the
solder police in their green uniforms would come rushing round to arrest you
before beating you up and throwing you in Eurojail for 20 years. I've
cleaned up the PC since then, but have found the following link to an
article written by a Dr Paul Goodman, who works for a well respected
institution who provide help and advice to industry on the technicalities of
this directive and associated issues. I had a number of direct conversations
with Paul to make sure that I was correctly understanding comments that he
had made in his document on the subject, and came to the conclusion that he
knew what he was talking about. The bit that refers to mixing solder types
is under the heading "REWORK"

http://documents.rs-components.com/E...g_and_RoHS.pdf

I'm sure with a bit of time spent, other similar comments could be found
again, unless there has been a serious genuine ( or politically motivated )
change of opinion by those that agreed with Paul, in the intervening couple
of years. The document I have referred to is still live - I've just checked.
In case that long link embedded in a news post gives any trouble, the gap
either side of the word "and" is filled with an underscore.

Arfa