In a message dated 96-11-16 00:47:32 EST, you write:

>We had also noticed a high level of sodium and >chlorine when conducting our
testing. 

How did you know it was Sodium and Chloride??  some ionic contamination
measuring
systems read out in units of Sodium Chloride, when in fact they do not really
test if the conductivity was caused by Sodium Chloride.

 My questions are:>1.  What would cause the ionic readings to intensify over
time?

The reason why I ask about the Sodium Chloride, and whether you are sure it
really is Sodium Chloride, is that oxidation, and especially oxides of Tin
and/or Lead will dissolve in some of the ionic contamination testers,  and be
read as "Sodium Chloride".   What you may just be seeing is oxidation, which
is expected to increase over time, and which would cause difficulty
soldering. 

>2.  What could be the possible origins of sodium and chlorine?  Could they
be
>introduced >in any of PCB manufacturing processes?

Rudy Sedlak
RD Chemical Company

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