Hi!

We're using a SEHO nitrogen wave soldering machine and are experience a
problem with solderability on boards and components.
Now we are testing a new mix of flux. We're mixing 50% of a no clean
flux (Interflux IF2005M) and 50% destillated water and an additional 2%
adipic acid. The theory of this is that the alcohol won't evaporate as
fast as it does and the flux have more time over the preheater to
"crawl" into the plated holes. The solderability increased and the
joints was less crystalized. But the problem was the contamination. It
also increased from a factor of 0,10 to 0,70. Our standards are below
0,15.
Has anyone tried anything similar or have any theory why the board
contamination increased that much? 
We have a theory that it wasn't the acids fault but the board. The
original flux also have a 2% solidcontent. 

/Jan Merstrand 
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