Mad Scientist Time - Making Printed Circuit Boards

Tonight was the highlight of the project.... mix some chemicals up and make the board!

Once again here is the schematic that I going to work with. (There is a minor change
or two on the board layout but it is pretty minor.) The schematic is laid out using
TinyCad. (Free/opensource software)

I found one or two minor issues with traces that I fixed after this image but this
is 99.5 what is on the board.

The board is laid out with FreePCB (Free/opensource).  From FreePCB I export
the CAM files into the Gerber format. I open the Gerber file with Viewmate from Pentalogix
(inexpensive program.) 

Tonight I took the project to the next level.


  • I cut down a section of copper board & sanded the edges

  • I cleaned the board with a green cleaning pad and then rinsed it with acetone.

  • I printed out a template on the laser printer to register where the "print and peel"
    needed to be taped down to go thru the laser printer.

  • I printed a mirrored image on the print and peel (taped to a 8.5" x 11" sheet of paper.)

  • I attached  the small piece of "print & peel" paper to the copper board with
    masking tape.

  • I put the board & paper under my iron for about 60 seconds moving the iron around.

  • I ran the board & paper thru my GBC laminator twice.

  • I put the board & paper under my iron for about 60 seconds moving the iron around.

  • I ran the board & paper thru my GBC laminator twice.

  • I put the board & paper in a container filled with water for a couple of minutes.

  • I removed it from the water & then removed the tape and paper.

Next set of steps:

  • I touched up any holes or questionable spots with a Sharpie marker.

  • Put on the chemical gloves & safety glasses.

  • I then mixed up the chemicals in a Pyrex (glass) container. 1 part 3% Hydrogen Peroxide
    to 1 part Muriatic Acid.

    (The Muriatic acid is "hydrochloric acid" that can be purchased at a hardware store
    for $5 a gallon. It is used to clean pools, stone, car engines, etc. It is VERY strong
    so be careful.) Add the acid to the Hydrogen Peroxide to make sure that you don't
    have a run away exothermic reaction.

  • Drop the board in the Pyrex tray and agitate the tray every two minutes. (Warm chemicals
    will make the process go faster.)

  • My first board took about 12-15 minutes. I could probably cut it in 1/2 with the etchant
    at 100 degrees F.

  • Once the board is done rinse / soak the board in water while you clean up.

  • Pour the etchant into a plastic bottle (using a funnel) for reuse later for additional

  • Rinse the Pyrex tray, funnel, bottles, gloves, etc under running water. Rinse out
    the sink REALLY well.

  • Remove the laser toner from the board with Acetone and a rag.

Ok I have to admit that initially I was going to only use the GBC laminator to heat
the board & paper. It did NOT get the board to the 300F/150C that is needed to
refuse the toner. It appears that this model only runs to 110C until it is hacked.
I am researching that piece but it appears that you replace a resistor in the thermistor
feedback circuit circuit. I am still looking for more detail as it would be nice to
loose the IRON set in this process.

I removed the toner from the laminator only test and reran the process with the steps
listed above.

Additional notes:

  • My first board has .020" traces with .120" pads. Since I am going to drill this with
    a small press I figured that I should make sure that I leave myself enough pad to
    work with. This board is only a single sided copper board.

  • I was worried that some of my traces would be undercut with the etchant. It was not
    an issue. I could easily have worked with .010" traces.

  • The process worked well enough that I could have used pin registration and two sheets
    of paper to make a double sided board.

  • I am now comfortable enough with TinyCad and FreePCB that I could crank out a schematic,
    board layout, and Gerber files for small/basic projects in an evening +/-.

73 de NG0R