Barry,

I'll give you a 90% chance that your problem lies with the solder mask.
Dry film masks are notoriously poor with some W/S fluxes, especially
some of the older ones (and 856 is hardly modern). The problem is
possibly purely cosmetic, but it may be symptomatic of something
serious, in view of the composition of the flux you are using. Have you
been able to do SIR  or ECMR tests? If so, results? Does the milkiness
disappear if you take a hairdryer to the boards and does it come back as
the boards cool off again or after a few days? Which solder mask are you
using? If you can answer these questions, we may be able to help you
pinpoint the problem.

Brian

Barry Gallegos wrote:

> Dear Sirs, Madams, Guru’s.
>
> I have an assembly that we processed thru SMT and then thru the wave
> solder operations. Wave solder flux was with Alpha metals 856
> water-soluble. The assembly is exhibiting a white cloudy / milky
> appearance that looks almost as if the laminate/solder mask has
> changed color. No matter how much we wash this assembly, it will not
> go away.
>
> Is this due to possible moisture in, around or under the solder mask /
> laminate. What is it andis it acceptable.
>
>
> Any advice would be appreciated.
>
>
> Yours truly, (wana-be guru.)
>
> Barry Gallegos
>
> Western Electronics.
>
> 208-377-1557
>

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