Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

This evening, I got both board edge lines on the silkscreen transfer to
completely overlay their corresponding 1.6 mil "traces" in the copper for
its full length of 2.6". These are 1 pixel wide lines, printed at 600 dpi on
a laserjet. To be clear, this is toner transfer, using Pulsar paper. While I
don't expect this to be typical or even repeatable, very good alignment is
easily possible without great effort.

I use common pins in the board corners to align the double sided artwork to
the board, and later the silkscreen. The pins are a very close slip fit,
almost an interference fit, in 24 mil holes. That makes them about AWG 22
ga. In Eagle, I put a via with a 24 mil hole in three of the corners, and
add a wire circle at the centers on the dimension layer so they print on the
silkscreen also. This only works if you drill before etching.

Wear cotton gloves when handling the artwork to minimize skin oil transfer.
To make up the sandwich, pre-pierce the holes in the artwork. Place one side
on the pins facing in, push the board on, and follow on with the other
side's artwork. Tape them in place before removing the pins; low tack
masking tape works best for me. Laminate and process as usual.

That's all. Easy alignment with no eyestrain or jangled nerves.