I wanted a sheet of ABS to do some prototype work so here's what I did.I took a piece of 3" pipe and cut a slot in it.Then I heated up the Oven to 300 degrees and placed it on a cookie sheet.I kept a close eye on it and after about 4 minutes I spread it out a bit and let it heat a few minutes more.I then placed a heavier pan on top for another minute or so till it was flattened.Then I took it out, placed it on the floor still on the cookie sheet, and held the top pan down hard for several minutes.This gave me a pretty flat sheet to work with.*WARNING!! Using the Wife's Oven and Pans in this manor can be hazardous to your health!