Etching

Warning: This is a work in progress, getting updated when I have time to work on it. The main part is done but I have yet to add photos and refine it more, sorry for the rough reading.

So you’ve got your board designed and ready to make a prototype, but you don’t know how. Thats what this is Tutorial is for.

Parts needed:

  • etching solution ($9.99 for a 16oz bottle at radioshack)
  • single or dual sided copper board ($3.99 for a dual sided board at radioshack)
  • glossy 28pound paper
  • a laser printer
  • backing soda
  • an iron
  • water
  • a plastic container that you can use for just etching
  • a sponge
  • a scottbright pad
  • soap
  • nail polish remover
  • a drill and small drill bit, .0625 or 1/16th bit should do
  • a board design (how to coming later) (if the board is dual sided, it should have at least two vias that are .0625 drill at places that they can’t be easily mixed up we’ll use then for alignment of the two layers)
  • rubber or latex gloves
  • a well ventilated area safe from pets and little kids
  • small bit of sandpaper

Now that you have everything lets get started:

  1. On your laser printer with the glossy paper, print out your board (both sides if you have a dual sided board) and cut the paper to about 1 inch (2-3 cm) around the pattern, set the paper pieces aside (try not to touch the paper or toner while doing this).
  2. Place your copper board on a table edge, with a clamp or two on each side and score both sides with a knife(if you can, it helps to clamp a ruler on top of the copper to keep the break line straight), after you’ve scored both sides, break the board along the score line (repeat if it’s to big in the other direction now). You should now have a copper clad board that is the right size.
  3. Take your little bit of sandpaper and sand the surface of the copper evenly and with a circular motion. From here on out you’ll need to wear the gloves to keep oils off the cleaned board, and protect your skin from the etchant.)
  4. With your gloves equipped, take your sanded copper board to the sink and put a drop of dish soap about the size of a 1/4watt resistor. rub the soap around the board on both sides for a few minutes, then using your scotbright pad, scrub both sides of the board in a circular motion. The point is to get all the sanded copper bits off and the oils off the copper you want to etch. after you’ve done this for a few minutes (5-10) rinse the board under water and be sure to get all the soap off. Dry it with a clean towel.Place the small drill bit in the drill, and set aside. take your cleaned piece of copper clad, and one side of your paper board pattern, and place the pattern in the middle of the board, tape it to the copper clad on the corners out of the way. With your drill, drill the vias that you are going to use for alignment of the two layers, when your done clean the holes out and make sure there is nothing between the paper and the copper clad.
  5. Tape the other side of the paper pattern to the copper clad, making sure you vias and all holes line up (it’s easy to get the top and bottom backwards of each other right here).
  6. Turn your iron to the highest heat and wait till it warms up. place the iron on the board and press down (I place the board in a piece of normal paper thats been folded in half sto keep the tape from melting onto the iron, I also apply all 100 pounds of me to the top of the iron :P) After a few seconds, about 10-20 the toner should start to melt, at this time you’ll want to move the iron around to make sure all places get even heat, flip the board over and repeat this for the other side.
  7. The toner transfer process should take about 5-10 minutes, and the paper may turn a little yellow or brown colored, at this point take the paper and place it in the cold water. Wait till the paper is fully soaked and start to remove the large pieces of paper, after a few more minutes of soaking the paper should be wet enough to get most of it off; rub the board between your fore finger and thumb until all or most of the paper is off.
  8. open your etchant bottle and pour about a teaspoon of etchant onto the sponge, and enough in the plastic container to cover the board. With the sponge in one hand the the copper clad(with the toner on it) in the other begin to rub the board with the sponge, after a few minutes the copper will be about half way gone, and after even more minutes the copper will start to disappear all together and soon all the visible copper will be gone, when this happens, place the board in the water to stop the etching and inspect it, if there is still some copper connecting traces then you can place the board in the plastic etchant and let it sit for about 5 to10 minutes per side.
  9. When all’s good and the board is done, get out your nail polish remover, and with some q-tips or cotton balls soaked in the nail polish remover, rub the toner, it should start to come off and after a few minutes of this the toner should be all gone and only the copper left on the board.
  10. Be sure to test the board to make sure the connections are good, if somethings connected use a hobby knife to cut it and hopefully fix the problem.
  11. Drill the holes, solder up, and enjoy your new board.

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