How to make your own PC boards quick and easy

There are many techniques for making your own PC boards. Each has its own advantages and disadvantages. The following tells how the designers at Glolab build their early prototype boards. We don't claim this method is the best but it works for us:

One of the quickest ways to make a PC board is with the direct toner transfer method. A PC board is designed with any one of many board layout programs available that produce Gerber and NC drill output files. Some of these programs can print a 1 X picture of your layout directly to a laser printer. If you have one of these programs, you don't have to use the Gerber file to make the board but it's good for checking your design anyway. If your program cannot print a 1X image then you can download a free copy of GCprevue by Graphicode that will allow you to view and print the Gerber data produced by your  program at any scale. Technical support for GCprevue is also available from the Graphicode web site.

Double sided boards can be made but we will describe only single sided because they are the easiest to make and will work for most circuits. First you design the board in your layout program as you would view it looking through the board from the component side. When it's done, you print it with a laser printer onto either a transfer paper or a plastic transfer film, both made and sold by  Techniks. The image will be printed the way you view it and then you can transfer it to the back or wiring side of the board. There are two types of transfer media available. One type is paper with a gelatin coating that you print on.  Another is plastic with a blue coating that you print on. If your layout program or printer have bold or high density settings, they should be used to get the heaviest possible toner output from the printer. A printer that has a straight paper path and does not fold the print sharply around a roller is preferred.

After printing is complete, the image is transferred onto the copper of the PC board by applying  heat that re-melts the toner and fuses it onto the copper. The toner is then used as an etch resist and the board can be etched immediately. Whether you use the paper or plastic medium, the transfer process is the same. The copper clad epoxy glass board must be thoroughly cleaned to remove every trace of oil (especially oil) and other contaminants. If you shear the board be careful of oil that seeps into the edges of the epoxy glass. Wash it in a solvent and rub it with 600 grit emery paper. If the board is not cleaned perfectly the toner will not adhere to the surface. Rinse well with cold water and dry with lint free paper.

The image can be transferred from the paper or plastic to the copper surface using an ordinary electric clothes iron. A little experimenting is needed to get the right amount of heat. If too little heat is used, the toner will not melt and if too much heat is used, the toner will smear and produce wide traces with rough edges. Place the board on wood or some other surface that will not absorb much heat. 

After transfer, the gelatin coated paper is immersed in water until the gelatin melts and releases the paper. This takes about 1 minute. The blue plastic can be just peeled off the board. We have found that the gelatin coated paper produces good traces but sometimes shows pinhole etching. The blue plastic avoids these pinholes by adding an additional coating over the toner, however, this coating sometimes causes bridging that must be removed after fusing by pressing and removing some mailing tape over the board.

The board can be etched in ferric chloride or ammonium persulphate. If ferric chloride is used it does not have to be heated although heating reduces etch time. Ammonium persulphate must be heated to about 100 degrees F.  Ferric chloride stains are very difficult to remove so don't get any on your clothes. You can buy both chemicals from Mouser or from a chemical supplier.

Make your own PC boards for GLOLAB projects. Download files that make it easy