PCB making

Making PCB is not that hard.

After having tried various methods I picked up the one explained hereafter. It might not be the best for everybody, but it does not require a lot of equipment and it is relatively cheap.

• A photoresist PCB board (check out ebay, I got 20 of them for $45) ;
• A software that can print your PCB artwork ;
• A inkjet printer ;
• A sheet of tracing paper ;
• An UV exposure box (learn here about how to make one) ;
• Some Sodium Hydroxide (you can buy it at your local DIY store) ;
• Some Aceton (DIY store as well) ;
• Some Hydrogen peroxide (130 volume) (that one is a bit more difficult to buy, try drug stores if your DIY store don't sell it) ;
• Some Hydrochloric acid (DIY store) ;
• medical cotton (optionnal) ;
• Water ;
• Several boxes in which your PCB can fit ;
• Gloves (if you don't want your skin to become white after touching some of the chemicals …).

You will need to print your PCB artwork on the tracing paper with the highest ink volume you can ask your printer for. That parameter can often be found in the printer parameters wizard available before you confirm the printing of your artwork. Wait for the ink to dry (several minutes) and take care of not scratching the tracing paper, otherwise you might end having damaged/merged tracks.

Put the tracing paper in the exposure box with a piece of PCB on it (sensitive layer facing the UV tubes of course …). Turn on the UV exposure box and wait for the exposure to end. The exposure time varies depending the material the sensitive layer is made of. This value if ofen indicated on the PCB package, but it also depends on your UV exposure box design. You may have to try several times with various timings on small PCB bits to estimate the best timing (mine is 1'45). At the end of exposure, turn off the UV tubes but keep the board inside the box, so that it won't be deteriorated by ambient light. <