sokos mark (msokos1@umbc.edu) wrote: : I am looking for advice on how to make *cheap* but good boards : at home. I don't have a laser printer. Is there any way to use a : dot matrix printer? I don't need itty bitty teeny tiny tracks, but : I would like something that looks good when I'm done. Similar to Leon's post, I've done similar at 2X photoreduced on a copier, but copied to onionskin instead of the normal paper. If you use sunlight as the exposure source with the photosensitive resist PCBs, the results are pretty good. I held 10mil tracks / 10mil isolation doing it that way. The resist will expose right through the onionskin. By far, the best results I've had were using honest-to-God photoplots, but if you don't have a photoplotting bureau handy, it's not an option. Most of the ones here locally (we have 3-4 in Phoenix) have a $25 minimum or so, but it'll save a lot of grief and frustration, and isn't nearly as sensitive to exposure times as either ink or laser toner. Figure about 6 minutes for the normal noontime exposure, and then work around it to find the optimum with a test piece. It won't vary much over the course of the year... One last suggestion: use the 1/8" shank solid-carbide drill bits that the real board shops do. If you ask nicely, they might even give you a box full of their `scrap' ones, and any of THEIR scrap will work for >500 holes for you. You aren't as picky about burrs or burning in the epoxy-fiberglass as the board shops need to be. Trying to use normal high-speed steel bits is an exercise in futility; they go dull quickly, and then you're punching holes instead of drilling 'em. If you *have* to pay for the right bits, I've seen them advertised in tool catalogs for about $2-$3 each or so, and they're well worth the money. They're a LOT more fragile than the bits that you'll get at the hardware store, but they *do* work well, especially with the 1/8" Dremel collet. For the tin-plate process, I never could get the electroless-tin salts to work worth beans. I finally gave up and just flood the board with liquid flux, then run solder along the runs with a fine tip iron. It's a lot more labor intensive, but it *does* work. Doing double-side PCBs almost required using the solid-carbide PCB drills, as the normal HSS bits will want to blow the pads off of the bottom side of the board when they punch through. The carbide ones cut through cleanly, and you have an excellent chance of getting the board to work. Make sure and leave a LOT more annular ring than you would for a production board, at least 20mils if possible, maybe more.