I'm sitting here working on a board, and I can't figure out something- it
seems like tradition that you don't put your soldermask over a via- that's
the default in Eagle* and how it has worked out in most layouts I've done.
Is there good reason for this with modern PCB fab equipment? I realize
that an un-masked via makes for an easy rework/test point.  I can also see
that I may not want to put mask over a hole (where there isn't board to
cover), but the silkscreen also seems to be left off where there isn't
mask, and I want to make sure I don't mess with my silkscreen (if I need
to get at the via, I'd rather scrape off the mask/silkscreen).

A friend got burned by poor plating a long time ago, and on his protos,
insists on filling the vias with solder- just in case the plating was
poor. Valid, but I haven't seen a bad via on my boards in years- if the
vias are that bad, there probably are other problems.

A google search came up with the possibility of trapping chemicals under
the mask in a drill hole, but that sounds like a more fundamental issue
with the manufacturing process.

Regards,

Matt

* You can adjust this property in Eagle Layout under 'DRC' -> 'Masks'

Matt Bennett
Just outside of Austin, TX
30.51,-97.91

The views I express are my own, not that of my employer, a large
multinational corporation that you are familiar with.
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