When i saw Creativeman's mosaic can out of Styrofoam...i wanted to make my own hot wire cutter...did a lot of research and came up with this version. I didn't like wires showing and I also wanted the arm to tilt....and be able to pack it away flat in minutes!

Step 1: Things You Need

Nichrome wire 30 AMG
PVC tube
PVC tube L connector
screw hook
wing nut and bolt
about 4 washes
dry wall screws
wires
Transformer
ac indicator switch
dimmer switch
Wooden box with lid

Step 2:

I've attached pictures and a diagram on which goes where.
Get the box...decide where you want the dimmer switch and indicator switch to be...I've put mine behind with the arm as i didn't want my kids meddling with the dimmer too much(i wanted hidden away!)
most indicator switches come with 4 prongs to light the led light in it ( this is optional....you can do without it....i wanted it to know if the current was coming or not without moving a piece of Styrofoam against the wire.)

Step 3: The Arm

Decide how long you want your arm to be and how high too. Cut 2 lengths for the height and width. Drill a hole at the end of the height tube, it should go all the way through...not too big as the bolt must fit well in to it...(you could pass a dry wall screw of approximately the bolt size instead of drilling)
at the end of the length tube
At the end of the height pvc tube screw the hook but not all the way through (you don't want it to come on the other side of the tube.
Remove the hook. Take the wire now and cut it to the length of the height + width+ L connected tube.
Remove the plastic at both ends of the wire...make loops with it...one to fit the hook... the other end to fit the bolt.
Now take the width tube...screw on the hook., pass the wire through it...remember to put the loop of the hook through the screw...
now go through the L tube and down the Height tube.
Pass the bolt through the hole in the end of the height ...Make sure the loop at the end of the wire goes through the bolt.
now push all the pvc tubes firmly and hot glue the wire loops. Do not hot glue the bolt! only the wire loop to the hole...make sure you can remove the bolt...while the wire is glued to the hole. (that way you can always remove the arm..and not worry about the wire springing up! Now paint it.

Step 4:

Now drill a hole in the center of one side of the box. Tie a wire to a washer...pass it through the bolt...pass the bolt in the hole through the arm and then a washer again and then tighten with a wing nut!
Cover both ends of the tube with styrofoam....just for beautification :-)
Now your arm is done...When ever you to tilt the arm...just loosen the wing nut and bend. if you want to store it fold it all the way flat ( your height of the arm must be more than the half width of the box to be able to do this).
Wire everything according the diagram with one of the wires from the transformer joining the washer in the arm, and and the other wire form the transformer should go through another washer. Now this washer should have the nichrome wire attched to it....which goes through a hole drilled through the lid ...and then attached to the hook ( here you don't need to add the spring even though i did.. the arm has enough of spring!)
Drill holes under the transformer ( this should be done before the transformer is fixed) for ventilation,
I think i forgot to say how to drill the hole in the lid...well....tie a string to the hook with something heavy at the end...see where it drops...check if it's perpendicular to the hook...mark it and drill a very tiny hole...just a little more than the diameter of the nichrome wire.

Step 5: Finishing!

now screw the lid...check if all is right...if it works...solder the wires and your good to go!
see...a clean cut!

You may want to add a fence. to get clean strips
Also use a square and drill tiny holes perpendicular to the wire on the lid so you may pin a piece of Styrofoam and cut perfect circles.
Once you have all these done....creating in Styrofoam will be a breeze!
Make one for a friend and gift it to them...I'm sure they would love you for it!