Step 3: Prepare the blank board
Cut your board to size, leaving a little extra room around the edges. I use a hacksaw, which leaves some burrs. Smooth any burrs off with a dremel or small file. You want the copper surface to be as flat as possible. Sand the surface of the blank board with 400-600 grit sandpaper in both diagonal directions in a crosshatch pattern. Then, use acetone on a paper towel to clean the board as thoroughly as possible. Grease spots are your enemy! Scrub the board really well.