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Subject: Re: [Homebrew_PCBs] Making hidden vias?

From: DJ Delorie <dj@...>
Date: 2006-12-08

"Stefan Trethan" <stefan_trethan@...> writes:
> And how much fun would it be to place 300 vias a board, manually?

More fun than soldering in 300 1/8" long wires.

> Also, with 300 vias a board you only get 3 boards out of your 1000
> pieces pack, for 15 pounds?

A thought I had... #30 wire wrapping wire is only 10 mils diameter; an
easy fit in a 13 mil hole. If you can cut it so that the end is
essentially flat (or flat enough), what you do is turn the board
component side down on a flat surface and clamp/tape it down. Then,
insert #30 wire into each via hole, solder, trim. When you flip the
board over, the wires should be flush with the surface, and you may be
able to solder them to the pads with minimal bump-out. Not sure if
it's flat enough for smd, but a copper braid may help to remove
excess.

I think if you have clearance issues under SMD parts, the solutions
could include (1) not putting vias there, or (2) pre-soldering all the
pads to raise the part up some. Maybe smashing the #30 so it's
thinner might help too. Or build a home electroless plating tank ;-)