Many of our Customers like to build their own experiment, and we often get asked if we know a good way to make experimental printed-circuit boards to test a new design. Here is the technique that we now use, and it works very well for us. It seems to be non-toxic, doesn't make much of a smell, and is fast and accurate. We can sometimes go from concept to a working pc board in 5 hours.
(1) We design our pc boards on our computer, and we use a program called "Board Creator" by Advanced Microcomputer Systems, Inc. their website is www.advancedmsinc.com/index.htm We bought a predecessor of this program many years ago, and just stayed with it... we think the company doesn't respond very well to it's Customers, but at least the program seems to work pretty good. We have about $150 invested in this latest version, which is version 3.0. This company offers a whole flock of different (and hard to understand) versions, but for simple pc boards, the one they call "Board Creator Std" for $US129.00 will make very nice drawings on any IBM/Windows98 computer. Some reasons we like Board Creator is the ability to control line-widths (important for microwave microstriplines) and the ability to use the mouse more than the keys on the keyboard to control the action.
We notice that Mouser Electronics also sells a decent economy pc board drawing program called "WinBoard". Their stock number is 526-WINBOARD/CD and the price is only $29.95 plus shipping. We used to use an early version of this program, and we don't remember how accurate you can draw the pc board lines, but it sure has a good price and is sold by a reputable company, Mouser. Go here to order it if you want: http://www.mouser.com/
(2) Getting the computer to draw what you want is about 2/3 of the work! Once you have a decent pc board on your computer screen, you need to print it on white paper and proof-check everything! Measurements (does it fit the box I want to use?), does it have mounting holes, are the holes the right size for my components, is anything printed backwards, and do the traces all go to the right places?
(3) Once you have a "perfect" design, the next task is to get it turned into a real pc board! We use a blue plastic sheet material that simply runs right through our H-P laserJet 5L printer. The blue sheet we use comes from http://www.techniks.com/press-n-peel.html. This stuff comes in regular-sized (for the USA) 8.5" x 11" sheets, and they feed through the printer just like paper. Print on the non-shiny side, and your printer will print a dark black image of your pc board on the blue sheet in about 10 seconds! In years of running this stuff through many printers, it has never got stuck or caused any problems to us...it works like regular paper. We now cut a sheet to a size about the size of the pc board we want to make, and save the rest of the blue sheet for future projects. Try and keep your fingers from touching the matte side (the less-shiny) side of the plastic sheet, as finger-oils will transfer and make for a less-perfect job when done)
(4) Now that you have the blue sheet printed with your design, the next thing is to properly prepare a small piece of pc board laminate... we pick a piece about a inch larger than our design, and we clean it extra good under running water, using a non-greasy household cleaner. We find that SoftScrub works best for us. Don't "clean" the pc board with a Brillo pad or any such cleaning pad that actually contains grease and oils, it won't do the job. Just use your fingers and a tablespoonful of SoftScrub. When the pc board is really clean, the water will "sheet" off the board, and it will not retain any little "droplets" of water...it should be just the opposite of a shiny new car finish..you don't want the water to "bead" at all! After the pc board is really clean, it will air-dry in about 10 minutes.. don't touch it anymore with your fingers, as they will deposit oils back onto the board.
(5) Once the pc board has dried out completely, it is time to use an ordinary household flat-iron to transfer the pc pattern from the blue sheet onto the super-clean piece of pc board. Find a really and truly flat surface that is smooth, and lay the piece of pc board there. Pick a place that can get somewhat hot, and don't ruin your wife's new counter-top! Put the blue sheet over the clean pc board (you didn't touch the blue sheet with your fingers, did you?) with the black pattern next to the pc board. Then take the flat-iron, which you should pre-heat to a temperature that is about right for ironing wool sweaters...rather hot, but maybe not quite 100% of the heat possible).. you can tell when you get it too hot..the blue plastic will really curl up! Better to start a little less hot, and keep raising the iron heat, until you notice the blue plastic begins to curl just a bit...then press hard for 15 seconds, moving the iron around to distribute the heat, until the entire pattern has been well heated and has transferred to the pc board. This is not as hard as it sounds, but sometimes the first time is the worst.
(6) When you think the pattern may be transferred, remove the heated iron, and let the pc board cool down. In a few minutes, it can be handled, and when it really cool, you can begin to peel the blue plastic away from the pc board. You should see the pattern stuck to the pc board! Done correctly, all of the pattern will transfer, and if you haven't used way too much heat, each component will be almost exactly the same size as what you wanted. Too much heat will melt the pattern and it might get a little large. Finish removing the blue plastic, and you will have the pattern transferred to the piece of pc board. Don't touch the metal with your fingers yet.
(7) To etch the pc board, take a quart of Ferric Cloride and heat it to about 120 degrees...we use an old milk-jug cut down to be only about 4 inches deep. We use our microwave oven to heat the ferric cloride, and there is minimal odor during the process. When the Ferric Cloride is heated (about hot enough to begin to burn your finger if touched), just dip the entire pc board into the ferric cloride and stir it gently around, using a plastic or wooden stick.. no metal! A note of caution here: Ferric Cloride can stain clothing and your work-area, so stir slowly! Drops splashing around will leave stains that probably won't come out... but with a little care, you needn't spill a drop, and after 5 minutes of gentle stirring, the pc board will begin to show the pattern as the rest of the copper is slowly etched away. It is OK to rinse the pc board under warm water for inspection, and to replace it into the Ferric Cloride if needed...here ia link to a good supplier of Ferric Cloride: http://www.kepro.com/howto.htm#E-type. Ferric Cloride can be re-used several times, and you will know when it is time to dispose of it, because it will take longer and longer to do the job of etching your pc boards. We take our used Ferric Cloride to a collection-point for disposal that our county arranges twice each year.
(8) Once you are sure the pc board is completely etched (no more copper remaining except under the pattern black lines and areas) then you can clean the pc board. We use a Brillo pad or an SOS pad. For this step, it is OK to get some oily residue onto the pc board, as it will inhibit tarnishing of the copper you will see when you rub off the black traces and areas you have. Rub until the copper is bright, and you are almost finished!
(9) At this time, you could just drill the pc board and trim it to size, but if you want, you can add a tin-plating to the copper lines and areas...most commercial pc board makers do this, and if you want to do yours, here is the supplier of a good tin-plate solution: http://www.kepro.com/howto.htm#ITP If you choose to do tin-plating, you should once again re-clean the new board with SoftScrub so it has absolutely no finger oils or SOS pad oils remaining.... just stir the tin-plate solution, and dip the board into the tin-plate solution. Let it stand for 15 minutes, and out will come a nice shiny tin-plated pc board that will readily accept solder, even after storage for months! Tin-plate solution should be kept in a cool or refrigerated spot, or just make enough for each experimental board...it will keep as a solution for several months if kept cool.
(10) Some pc boards will need holes punched for mounting holes, or holes drilled for leaded parts, or other mechnanical work done to make a professional-looking pc board. Many of these things are very easy to do, and here is a link to a supplier of a cheap drill and a cheap punch-set... here is the punch: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44060, and here is the drill: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=37486
We find this method of making experimental pc boards to be quick, easy, clean, and non-toxic. When we do get a pc board that we like, and it works when built the way we designed it, then we print a copy on a high-quality white piece of paper, and send it to http://www.cl.ais.net/farcir/ FAR Circuits can make you any number of pc boards that are even nicer than the one you made yourself! For one or two pc boards, FAR wants maybe $50, but when you order 25 or 50 little pc boards, their prices drop down to only $2 or $4 per board...certainly good enough for a club project, or for a small company. FAR is a very honest and friendly maker of pc boards.