|The 11 mil Via holes are Stitched|
With Stripped 8 mil Wire Wrap Wire
The current board is slightly wider than a 16x2 Character LCD module and other dimension (height) allows the switches and header to be exposed below the mounted LCD. Note: the LCD plugs in via a header across the top of the board, and in normal use, the LCD would typically be mounted remote.
|Stitched Loops of Wire Wrap Wire|
The very thin stripped Wire Wrap Wire is 8 mils in diameter, and the via holes are 11 mils (a tight fit), the via pads are 40 mils. Note: 8 mils are less than the thickness of 3 sheets of typical bond paper, but I really enjoy working on microscopic projects.
Once all holes are stitched together, the loops are bent tight to the board and then cut just out side of the edge of the pad with an X-Acto Knife. Wire Wrap Wire cuts very easily with a gentle wiggle of the knife. The loops on the backside are left in place to hold the wires in place.
After each via is soldered from the first side, the "cut and solder" procedure is repeated on the other side. Care must be taken to avoid heat transfer to the opposite side solder joint, even as small as the Wire Wrap Wire is, it can transfer enough heat to melt the backside solder (if to much heat is applied).
A very-very fine tip soldering iron is used with very fine 15 mil solder.
Because the stitching process is somewhat random, the Wire Wrap Wire is typically bent in to a "Z" shape, with a short flat tail on each side of the board.
I make a Microscope video with a USB camera of the process, but it did NOT turn out. I need to find an adapter for my good low light camera.
About one half of the parts are installed now, but a few (i.e., the 16 MHz Crystal) has not been ordered yet (maybe tonight).