Step 6: Transfer the ink onto the copper
First, you want to take a piece of steel wool to the copper sheet (both sides), and buff it until the entire sheet is shiny.
If your transparency is much larger than the copper sheet, you can trim it down, but leave some (.5 inch) room on the sides of the image.
Now, plug in your iron, and set it to a hot setting.
Put your copper board down on the ironing board. Position the transparency over it(ink side facing the board!). Put a piece of wax paper over the transparency.
Now, being careful not to slide the transparency around, put the iron on top of the wax paper. Press down with the iron, and iron all around the transparency . Iron for about 5 minutes--if you iron for less, the ink won't transfer well and you'll have to do it over again.
When you're done, set the iron to the side. The copper boards will be very hot!
I found that the ink will transfer best when the board cools down. You could either wait for ~10 minutes, or, if you're impatient like me, you can carry the board to a sink (remember that it's really hot!), and run some cold water over the other side of the board. This will cool the board down in about 10 seconds.
After the board is cool, peel back the transparency. Most of the ink should have transfered to the copper board. If you notice that it only partially transferred, it's OK. Leave the transparency on the board, put the wax paper on it again, and iron some more.
When you see a pretty faithful representation on your board of your image, you're done. Onwards!