I am building an acrylic box 24 x 24 1/8" thick with 1" sides and 1/2" returns on the back. I am v-grooving the folding lines. Everything works fine except the finish parts is warp on the sides how do I prevent this? I am doing anything wrong. I am using a coil heating element 220v it takes about 30s per line to heat and bend.
Help please...