A printed circuit board, or PCB, is an essential part of any electronics construction project. The board adds durability and reliability while allowing you to build sophisticated circuits. If you need only small quantities of circuit boards, you can make custom PCBs yourself at home safely and inexpensively. The process involves developing the circuit art on a computer, printing it, etching away unwanted copper, and drilling. With some practice, you can turn out your own professional-looking PCBs.
Instructions
1 Create a PCB pattern from the circuit's schematic design with computer software. Programs such as expressPCB will automatically create correctly-spaced printed circuit layouts from a schematic you enter. When you print the circuit board pattern, it needs to come out as a mirror image of the original so that it will transfer correctly to the board. Check your software and printer settings before you print.
2 Rub the copper board with the scouring pad under cold water to remove oxides. The copper should look as shiny as a new penny. Dry it with a soft towel. If the board has a protective peel-off plastic film, you don't need to scrub; simply remove the plastic.
3 Place a few sheets of glossy laser photo paper into the printer's manual feed slot. Set the printer to print at maximum toner density. Print the PCB design as a mirror image onto the glossy side of the paper.
4 Set the clothes iron to maximum heat. Set the flat wooden board on a sturdy surface. Place the PCB copper-side-up on the wood board.
5 Lay the printed circuit pattern on top of the bare PCB. Orient the paper so the pattern lines up exactly with the board. Set the hot iron on top of the board and press down hard. After about five seconds, slide the iron slightly, taking care to not move the paper. Moving the iron heats the paper more evenly.
6 Remove the iron after about five minutes, or three minutes for small boards. Pick up the board with the pliers and place it in the tub of warm water. Let the board soak for a half hour.
7 Peel the paper off of the board. Some of it may stick to the board, so use an old toothbrush to scrub it off. If any paper stays on the toner traces of your circuit artwork, you can leave it in place.
8 Check the traces against your original PCB artwork. If you see any serious smearing or cracks in the artwork, you can wash the toner off with acetone, print another page, and repeat the process beginning at Step 4.
9 Put the rubber gloves and safety goggles on. Place the PCB in the shallow tray copper-side up. Pour ferric chloride etchant into the tray, covering the board to a depth of about ¼ inch. Watch the etching process carefully. When you no longer see copper, remove the board and rinse with cold water in a porcelain basin. Copper remains underneath the toner.
10 Remove the toner with the scouring pad and acetone. As the toner comes off, it will reveal bright copper traces. Clean the board until you remove all of the toner and the paper remains.
11 Drill any holes needed in the board. Use the 1.0-mm bit for standard component leads, such as resistors and capacitors, the 1.2-mm bit for larger leads and the .8-mm bit for integrated circuit and other thin leads.
