Hi Paul!

I had an experience with what we called "Blue Solder" once, but it was traced
back to our cleaning process...you can see a picture of it on my web page at:

http:www.stevezeva.homestead.com and look at "Blue Solder". What we
discovered was that the airknife cycle in between the wash and rinse cycle was drying
out the chemistry on the solder joints before we could get it rinsed of. Once
we shortened the airkife cycle, the appearance went away. This was dealing with
63/37 solder too, not SN96 solder...

Dave Hillman has some pictures on my page next to the "Blue Solder" one, he
called "Barney Boards" because of the purple appearance of the solder. I can't
quite remember what the situation was with that...maybe he will see this and
refresh our memories.

-Steve Gregory-


> We just ran a long time heat run at 175C on a board made with Sn96/4Ag.
> The leads turned blue.
>
> I don't have my CRC handy. What caused the blue? Is it silver halide? IS
> there another tin oxide I am not aware of which turns blue? Or even
> copper?
>
>
>
>
> Paul Stolar
> Materials/Reliability Engineer
> Manufacturing Reliability Lead Engineer
> Baker Atlas
> 713-625-5376
>


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