A deceptively simple way to accurately etch double sided PCBs with no jigs or special equipment.

1] Print out you’re two plots on ‘laser film’, remember to mirror the side 1 plot.

2] On a light box, line up the two plots, emulsion to emulsion, as accurately as possible, it helps to tape down the first plot.

3] Now fold back the top plot, and stick a strip of double sided tape to the bottom plot, as far from the design as possible, so you now have - top & bottom visually in perfect alignment and secured together.

4] Get your PCB material and cut it to larger than the finished board size in one dimension, and tape it down to, say plot side two.

5] With the board stuck down, forming an envelope of side two, board and side one, put in the exposure light box and smooth down to create a known distance from the double sided tape join to the board.

6] After exposing side one, turn the board and art work over and again smooth down to create the same distance offset for side two, expose and you’re alignment should be spot on.

7] Keep turning the board over in the dev tank to ensure both sides are doing OK, and check the same in the etch tank. I recommend using Farnell developer #141-310 & Fotoboard for totally reliable results down to 0.015” line widths.

Good luck.