I used 5/8 pressed board. There are several threads with pictures right here, just use the search. I even found a few on You Tube! I bought a 4x8 sheet of wood & had Home Depot cut it into 2 24"x 50" pieces. That left me with a piece 3'x4' for another use. When I got home my husband trimmed off 2" on each board to make the board 22" wide. Then he cut that piece in half & used it on the under side so it won't slip off of the ironing board. We were worried about the weight but it's been fine. I like having the extra foot to hold my iron, water spray....etc. Also it's nice for pressing the finished quilt top. He also ran the router around the top edge to make it easier for the fabric to slide down after ironing. The hardest part may have been making sure the fabric was really tight with no wrinkles. I used a plaid that I had hanging around for a long time. It works great to match up the edges on the fabric when I iron so it doesn't get distorted (I iron wet fabric straight from the washer)