DIY Foam cutter

Or, how to shave a yak.

I built a basic foam cutter table over the past weeks. The cutter table measures 15" x 10", and the mounting arm is about 6" off the table. Here is a 3d sketch with some rough dimensions:

I've tried to make it as simple as possible. The table is made from 4 pieces of 2x1, glued then screwed together. The table top is made from a thin sheet of mdf, with a 3/8" hole where the cutting wire will pass through. There is a stud along the bottom that holds an eye screw where the bottom-end of the hot wire will be hooked up to. Finally the mounting arm is made from 2 more 2x1 pieces of wood, mounted with a 3/8" bolt to the base, and an eye screw for hooking up the top-end of the hot wire.

I ordered some 32 gauge NiChrome 80 wire from eBay to serve as the hot wire. Since the wire is 6 inches in length, it has a resistance of about 5 ohms. Hooked up to a 5V power adapter, this will produce around 1 Amp of current, which will raise the temperature of the wire to about 700 degrees Fahrenheit (or about 370 degrees Celsius), which is enough to cut through most foams.

If you are interested in the math behind this, hotwirefoamcutterinfo.com has lots of data for you.

Here are some wip photos of the unit:

I also built a simple fence, which is squared to the front edge of the table, as well as a simple circle cutter. Here are some photos of the unit in action:

This will become the new base for the dreadnought diorama. Stay tuned...