DIGITAL CLOCK
Draw the schematic and the PCB.
Print the PCB to a glossy photo paper. To by productive print many design in one paper.
Cut the PCB.
Flip the glossy photo paper into the PCB and use the iron as in image.
After you finish it will looks like this.
Put some FeCl 3 on hot water.
Put the PCB on it.
After a while get it out and wash it with water.
Cut it to the exact size and clean it.
Print the green mask, any type of ink will work fine. I use silkscreen ink mixed with varnish. after printing the ink, dry it with hot air or in the oven.
Drill it.
Assemble the component.
Apply the tin to the patches in the edge.
Test every board alone then assemble them.
WOW.