Hi Niel,
I have a PCB design freeware program I downloaded some time ago, but am too lazy to learn it. I designed the PCB layout in Excel, from a diagram taken off the internet, sizing the columns/rows to give the correct dimensions for components when printed on paper. Make sure all the traces in the diagram are drawn in (ask me how I know !)
I used single sided PC board cut to the required size. Double sided boards are available which allows traces to be made on both side for more complex designs.
I cut the paper design to size and glue it (Pritt) to the copper clad side of the board. I marked all of the holes for components using a sharp centre punch, before removing the paper and cleaning the glue off. I drilled 1 mm holes for all the components and cleaned the board with methylated spirits to remove grease residue.
I marked the traces using an ordinary bullet tip permanent marker, taking care not to touch the copper board. Initially I draw the design by freehand, but the one in the photo was done with a ruler which makes it look a lot more professional. Make sure that the trace is fairly thick (thick, not wide) and there are no missed areas.
The board was immersed in a shallow dish of Ferric Cloride solution (available at most electronics component stores either as a solution or crystals), enough to just cover the board, and left for around 15-20 minutes, agitating regularly, until the copper had etched away, leaving the traces untouched. I used around 35ml of Ferric Chloride in a small container to do the board in the photo.
After the etching was complete, I washed the board in cold water, dried it, and cleaned it with meths to remove the marker ink.
Take extreme care and use rubber gloves when using Ferric Chloride, as it is highly toxic and very corrosive. It dissolves all metals so use plastic or glass containers for etching. I disposed of the used Ferric Chloride down the drain, flushing with large volumes of water.
I reused the Ferric Chloride once only, and it markedly lengthened the etching time of the second board.
Also, if going the route of making multiple boards of the same design, do one first to try out and make sure it works first (don't ask how I know)
Cheers,
Steve
