Making PCBs at home

This is the process I've used for producing PCB's at home. Similar processes are documented far and wide across the web, and can be consulted for additional details.

  1. Design board in Eagle. Avoid thin traces and narrow gaps between traces. Running wires between pins on through-hole pin header is unlikely to be successful (the same is not true of surface mount pin header - see my Eagle library). For home assembly, I recommend using 1206 resistors/caps/LEDs, rather than the smaller ones now available. PCB realestate is cheap for home fab, and soldering miniscule parts without a reflow oven is not fun.
  2. Set only front, pads, and vias to show. Export image as a .bmp with 300dpi.
  3. Open image in paint. Use fill tool to make it black and white. If needed, hand-draw any modifications necessary to make them easier to fab. This may mean trimming the edges of pads, touching up corners. If you are going to make more than one at once (recommended - in case some don't come out), make some copies. Finally, mirror the image .
  4. Print image onto Hammermill Color Laser Gloss paper. In paint, you need to go to File -> Print -> Page Setup, and under Scaling, choose "Adjust to 100%".
  5. Cut out the paper with the pattern printed on it.
  6. Cut blank board to size (leave some space to tape the paper to). Make sure the edges of the copper side are smooth - you do *not* want a ridge at the edge, as it will impede proper toner transfer. Remove any such burr with a file.
  7. Lightly clean blank single-sided board with slightly abrasive scrubber, rinse with rubbing alcohol and wipe clean. Allow to dry completely.
  8. Place paper face down onto the blank PCB, and hold in place with small pieces of tape.
  9. Thoroughly, but carefully, iron the paper onto the PCB. Use iron on high heat (no steam), or similar tool. This requires some technique, as being to aggressive - holding the iron on too long, and/or pressing too hard - will squish the toner around and potentially bridge traces. However, if not enough heat and force are applied to all parts of the board, the toner won't stick.
  10. Let board cool, then put into water for 30+ minutes. You can gently run your fingernail over areas that don't have toner to break up the surface of the paper, allowing water to penetrate more quickly.
  11. After the paper has turned to mush, gently work the now-mushy paper off the board with your fingers.
  12. Examine board and make sure the pattern was transferred well. Bridged traces can be (very) carefully separated with a razor or the tip of a pin, and missing spots can be filled in with a dab of nail-polish. Hold the parts up to the pattern on the board, and compare it to your design. Make sure all the pins line up like they're supposed to. It's a bummer to find out that you forgot to mirror the board or something like that after you etch.
  13. Etch the board using any PCB etchant. I use Cupric Chloride in HCl, and regenerate it by adding small amounts (1-2ml per board) of 35% hydrogen peroxide (this is now readily available, because some fad diet advocates adding it to your food), as it is inexpensive, clear enough to see the board as it etches, and can be reused indefinitely, minimizing the need to dispose of toxic copper solutions. No matter what etchant is used, gentle agitation makes a world of difference in the etching speed - a magnetic stirer is very helpful in this regard. Be sure to take appropriate care handling (and disposing, if applicable) the etchant. Etchants will stain stainless steel and many other surfaces, and contain soluble copper, which is mildly toxic, and may cause burns on contact with skin.
  14. Wash board thoroughly after etching. Remove the toner (and nailpolish, if you had to fix anything) with Ethyl Acetate (sold as "MEK Substitute" in paint stores).
  15. Hold board up to light and make sure that the board is okay. Fix any bridged pads/traces with an xacto knife.
  16. Drill the holes using carbide PCB drills and either a high-speed drillpress, or a dremel with the drillpress kit. Either way, hold the board firmly, and wear eye protection at all times. Carbide PCB drills are a consumable, and routinely break (another reason to wear eye protection) - always have spares.
  17. Use an immersion tin plating solution ("Liquid Tin") in accordance with the manufacturer's instructions. This will protect the copper from oxidation and make soldering easier. Improper application of tin plating (creating a very thin layer due to insufficient plating time, or using old or depleted plating solution) may have the opposite effect, making the pads nearly impossible to solder to.