Step 3: Making the Mold
Take the pitcher and measure down 6" from the top. ( I cut mine at 5" and it's a little short) Mark a line around the circumference. Cut the pitcher at this line and remove the handle. I used a Japanese hand saw but use what you've got. Smooth the cut edge with sandpaper or you can just gently scrape it smooth with a piece of metal like the edge of a ruler.
Place the cylinder with what used to be the top of the pitcher on the counter. The cut edge will be a circle facing up towards you. Take a pencil and divide the circle into 16 sections. I do this by first by dividing it into quarters then dividing each quarter in half and finally each eighth in half. I just eyeballed it but you can measure if you want. Use a small square and draw vertical lines down the cylinder from each division mark so that you have 16 equidistant lines. Use a ruler and place horizontal cross marks on every other line. Space them an inch apart starting at the bottom and going up to the top. Then do the same thing on the lines you haven't marked yet but starting 1/2" from the bottom so that you get a staggered grid wrapped around the cylinder. You should end up with something like the picture below.
Take a piece of scrap wood and clamp it in a vice or to a counter so that you can slip the cylinder over the wood which will support it as you drill holes. Drill 5/16" holes through the wall of the cylinder at the cross marks. Pick off any sharp bits.