Foam can be purchased at any building center. I create most of my projects with white bead board. Beadboard is the cheapest and works fine for rolling hills and valleys common to most modeling projects. Any type of foam will work, better detail can be obtained from dense foam, blue or pink being the denser. For our use ask the clerk if their is any damaged stock available at a discounted price, you'll cut it up anyway.
For construction of the foam cutter you'll need the following.
1) 25ft. Grounded extension cord.
2) Square double electrical switch boxes ( handy box type).
1) box cover with a switch and receptacle hole.
1) Standard wall receptacle.
1) Grounded plug.
1) Wall dimmer switch (push on/off, turn for brightness).
1)Furnace transformer 24volt (20VA. or better power) Call the furnace/ air conditioner guys they will have good used units from furnaces they replaced.
1) Nichrome wire, available at you Hobbystore or email me.
1) 1/16 and 3/32 model airplane wheel collars (hobby store).
1) 10ft length of lamp cord.
1) Incandescant nightlight with manual switch.
1) 12x12 board to mount your project on.
1) Basic shop supplies (Cutter, knife, tape etc.)
Measure 2 ft back and cut the receptacle end off the 25ft cord, you'll use it as the supply cord. Screw the 2 handy boxes to the 12x12 board about 1" apart. Punch one of the knock outs from one of the boxes and run the end of the 23' extension cord through it. Connect the black wire to the switch and the white wire to the silver screw on the wall receptacle. Connect the green wire to one of the screws holding the box to the board. Cut a short piece of wire to connect the other screw of the dimmer to the brass screw on the receptacle. Secure everything in the box and screw on a cover plate.
You now have an outlet with a dimmer switch. If you plug a lamp into it you should be able to turn the lamp on or off and dim it. I plugged a night light into mine to tell if it is on or off. Use a simple incandescent light! A neon unit will not work.
Attach the grounded plug to the remaining 2ft length of the supply cord and cut the receptacle end off. Punch out 1 knock out from the second box and slip the cord through it. Connect the black and white wires to the black and white wires of the furnace transformer. Connect the green wire to one of the screws holding the box to the board. Screw the transformer to the box keeping all supply wires in the box. Plug the transformer plug into the outlet next to the night light. You now have a transformer that can be turned up or down to regulate output.
The actual cutter is made by stringing the nichrome wire between some type of frame. I did this by cutting a piece of good grade 5/8 plywood into the shape of the letter "U." I made 2 of them, one with a space of about 4" and the other 13" wide.
Drill a 1/8" dia. hole in both legs of your "U" shaped cutouts. Thread one 1/16 and one 3/32 wheel collar on the nichrome wire. Thread the wire though one end of the "U" shaped wood frame and loop it back through the wheel collar, tighten it to secure the nichrome wire. Do the same at the other end. Make sure the wire is very tight! orit will expand and loosen when it heats up. Take the length of lamp cord and remove 1" of insulation from one of the ends. Twist it tight and connect it to one end of the nichrome wire by slipping it into the 3/32 wheel collar and securing the screw. Do the same to the other end of the nichrome wire.
Now you should have a cutter frame with a 10ft. cord on it. You will want to make several sizes of these nichrome wire frames for different cutting tasks. I installed a disconnect plug in the handpiece cord for easy change. Now that you have the basic idea you can design your own frame shape for the job you need done.
Connect the cord from the cutter to the two screws on the furnace transformer. Turn it on and turn the dimmer switch to achieve the proper heat in the cutting wire. Have fun and play a bit, you'll have a lot of fun creating shapes and carvings.
Remember this tool gets very hot, be carefull not to set it on combustable materials.
