MAKE YOUR OWN PRINTED CIRCUITS
To make smart looking PCB's, all you need is: A computer, a laser printer, copper clad board, etchant, a clothes iron and some Epson glossy photo paper. You can buy special film for making PCB's, but I have found that the Epson paper gives better results. I use Epson photo quality glossy paper for inkjet printers.
Draw the PCB track layout, using a CAD program or a standard drawing program. Remember to reverse the image before printing. Most drawing programs have a 'flip horizontal' function. Print the image on normal A4 paper to make sure that it is the correct size. Check the layout carefully.
Use a laser printer to print the image on the glossy side of the photo paper. Clean the copper clad board with steel wool or very fine wet sandpaper. Dry the board thoroughly. Make sure that the board is clean and free from fingerprints. Place the photo paper face down on the copper clad board. Use masking tape to hold the paper in position. Don't use vinyl tape. Place the board on a flat surface. You will be using a very hot iron, so don't use the dining room table.
I use the back of an old telephone directory. Use a hot clothes iron to transfer the track pattern from the paper to the copper board. Don't be afraid to use lots of heat and pressure. Allow the board to cool. Don't be tempted to lift the paper. Put the board in a container full of warm soapy water. After about twenty minutes the paper will begin to dissolve and disintegrate. Carefully remove the paper from the copper board. Rinse under a cold tap to remove paper residue. You may need to touch up any broken tracks with an etch resist pen. I use a fine Staedtler laundry marker.
Etch the board in a Ferric Chloride etching solution. You can buy the etchant in liquid form or as anhydrous Ferric Chloride powder. Follow the instructions. NEVER add water to dry Ferric Chloride. Don't get any on your clothes.
After etching, rinse the board under a cold tap. Remove the etch resist with some steel wool. Dry the board.
Use a 0.8 or 1.0 mm drill to make the holes for component leads.
The close up picture shows that the tracks are not as clear and well defined as they would be if the board was produced by photographic methods.
The procedure for making double sided boards is a bit tedious. Coat one side of the board with aerosol paint or clear lacquer. Etch the other side of the board as for a single sided board. Remove the paint or lacquer. Drill the component lead holes. Paint the etched side of the board. Then etch the unetched side of the board as for a single sided board.
It is difficult to line up the two sides correctly. Use the component holes as a guide.
I have used this method to make PCB's for both DIL and surface mount IC's with 0.05 Inch pin spacing.
My laser printer is an old Apple LaserWriter II NTX (300dpi.) If you don't have access to a laser printer, use an inkjet printer to print the layout on ordinary paper, then copy the image to the Epson paper, using a photo copier. I haven't tried this method but it should work.
Update: Oct. 2001.
I have also had good results with an OKI LED printer. I have found that Xerox paper works
just as well as the Epson paper. I buy it in packs of 20 sheets.
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