Hello Alan - here are some comments to your inquiries:

Are all bar solders alike?  All claim to exceed the requirements of
J-Std-006.

** My experience has said that if the solder bar meets the requirements of
JSTD 006 (perviously QQ-S-571) that there isn't much difference. We did
recently go through an experience of procuring two different solder bar
part numbers from a vendor (both the same alloy and both met 006) where one
bar caused substantially more pot drossing. A SEM analysis revealed that
one bar contained a small precentage of zinc.

Are there any substantial differences between ultra-pure, virgin, etc.?

** IMHO, no. Some solder vendors claim that the ultra pure bar has better
fluidity, less surface tension, etc. Once you run a day's worth of
production through your wave solder machine you have "contaminated" the
original solder bar alloy chemical composition enough that I believe the
claimed advantages of the solder bar purity is lost (and why pay more for a
one day advantage). Some solder vendors have been working with alloy
additions that lower solder drossing characteristics (one example is adding
Phosphorus) that some people have told me has made a difference in their
process.
Any advantage/disadvantage between 60/40 & 63/37?

** Both are near eutectec solder alloys used by lots of folks with equally
good results. The Sn63 alloy has a slightly smaller pastey range but in a
wave solder pot with many, many assemblies going through it I again think
that it would be tough to show a statistical difference.
Is there in easy method to evaluate the solder performance other than
dumping 1000+ pounds of solder and re-filling with the new solder?

** I have seen some nonreleased data on a Sn63 versus Sn60 solder alloy
comparison using a min-wave solder pot and small test coupons (the results
were inconclusive - a larger sampling size was needed) which is one method
of avoiding the dumping of a big pot. Sorry, but if you really want to do a
good comparison your idea of using a full size wave solder machine/pot
would give the most useful (and applicable) results. Good Luck.

Dave Hillman
Rockwell Collins
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[log in to unmask] on 12/03/97 09:34:59 AM

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cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
Subject:  [TN] Bar Solder




A few questions on bar solder used in the wave solder process . . .

Are all bar solders alike?  All claim to exceed the requirements of
J-Std-006.
Are there any substantial differences between ultra-pure, virgin, etc.?
Any advantage/disadvantage between 60/40 & 63/37?
Is there in easy method to evaluate the solder performance other than
dumping 1000+ pounds of solder and re-filling with the new solder?
Or does it just come down to cost (per pound)?
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