In general, based on practical experience, I think I would agree with you. I
have also reworked joints on boards that were built with lead-free, but not
subject to the European regs, with regular 60/40 lead solder, and I have
never knowingly had a problem - at least short term. But who's to say what
the long-term effects may be? I mentioned in my original reply about the
'metalurgical wisdom' in this regard. I got this direct from conversations
with a Dr Paul somebody-or-other who is an expert in the field and head of
the subject for a UK consultancy firm, when I was researching for an article
that I was writing on the subject, for a UK trade magazine. He had produced
a paper which was available on the 'net, and he was quite adamant that the
two solder types should not be mixed in the same joint, because of long term
degradation of the integrity of the joint. I've no idea whether this belief
was theoretical or based on experimentation, as I did not ask the question.
That sort of depth was beyond the scope of the article.
On balance, I still feel that the right *overall* practice, is to rework
joints with the same basic formulation as they were made with. Obviously,
it's not going to be a major problem if a reworked joint in a TV set or
whatever, fails down the line because of it having been reworked with the
wrong solder type, but I would hate to think that some item that I had
repaired finished up in a critical application, and later failed because of
me. Remember also, that most of us outside of the USA are in a slightly
different position from you folks in that we must not, officially under
threat of law, do anything to compromise the RoHS certification of a
product. That includes using non RoHS compliant replacement parts, and
solder to fix them in with ... :-\
Arfa