DIY CNC Hot-Wire Foam Cutter

Cutting and Drilling

• 1

  Cut one of the two wood yardsticks in half, using a table saw or a table jigsaw. On the two halves, drill 1/4-inch holes in the middle of each and additional holes at the end of each stick, about 1/2 inch from either end of the stick.

• 2

  Drill one hole about 6 inches from the end of the fully intact yardstick that already has a hole in it. Drill another approximately 1 inch from the far end of the stick. These yardsticks will serve as the frame for your cutter.

• 3

  Insert bolts through the holes in the center of the short yardsticks, and through the holes that you drilled in the large yardstick.

Arrangement and Connection

• 4

  Arrange all three pieces in the shape of the letter "H." Keep them connected using a nut and a washer, but don't over-tighten the sticks together.

• 5

  Insert machine screws through the ends of the "H" where you have holes drilled. Insert the screws with one washer on the side with the screw head, and two on the side with the nut. Put the nut on the end of the screw, but do not tighten.

• 6

  Cut the outlet end off your extension cord, and expose the two wires inside by stripping off about 1 to 2 inches of the outside insulation.

• 7

  Strip the inside wire insulation off each piece as well. Attach the bare wires to the machine screws by bending the bare wire around the screws on the side with the two washers and the nut. Place the wire between the two washers and tighten.

• 8

  Pull both ends apart as much as needed to create some slack. Secure the slack to the yardsticks using plastic wire ties. The machine screws will serve as your power terminals. The wire should now form a "Y" shape.

• 9

  Cut a piece of string approximately 6 feet long, and tie a loop through both holes at the end of the "H" that have yet to be used. These holes are on the end opposite where you attached the wires.

• 10

  Tighten the string enough to pull the legs of the "H" perpendicular to the middle yardstick that connects them.

Wiring

• 11

  Attach the hot wire by using a guitar string, looping it around one of the machine-screw terminals. Attach the string by making a loop in one end, and then feeding the end of the string through the loop. When you pull the end of the string, the loop will tighten.

• 12

  Place the wire closely to the nut on the machine screw, and then wrap the wire around the terminal on the other side. Tie it so that the string is taut, but not overly tight.

• 13

  Tie cross-string supports from center holes of the "H" support to the end of the yardstick with the support string you already cut. The end result should be an "X" on the end opposite the power terminals.

• 14

  Wire the transformer and the dimmer switch. These switches can be wired by repeating the same basic wire-stripping method you used at the beginning of the project. Use one of the wires to connect to the dimmer switch and the transformer.

• 15

  Connect the dimmer switch to the transformer with the remaining wire. Use a third extension cord to attach to the transformer's hot wire. Connect all wires using wire nuts, or electrical tape as a minimum.

• 16

  Place the dimmer switch inside a plastic project box and tape the switch in place, ensuring you leave room for ventilation in the box.

• 17

  Plug in the box -- with the dimmer switch all the way in the off position. Slowly turn on the dimmer, and gradually allow it to increase the temperature of the guitar wire.