Using Foam-Cutting Tools

Many Halloween projects make use of plastic foam. This material is light and easy to work with - if you have the right tools.

This page assumes that you have bought or built foam-cutting tools.

Safety

Electrical issues
- line isolation - It is dangerous to hook anything directly ("DC path") to the main power lines. In our setup, we use a transformer to provide "line isolation" (as well as a lower working voltage).
- high voltages - All of the electrical connections up until you hit the high side of the transformer are at line voltage, which is dangerous. In our case, everything on the high voltage side are comercial components that simply plug toether.
Materials - Many of our tools have handles of wood or plastic. Since plastic can melt and wood can char and burn, you have to be very careful about this! We used wood because it cheap, easy to find, and can easily be modified - by backing out the screws and putting them in another place. The places where screws hold the hot wire to the wood seem to be OK, because we put a ring terminal (crimped to the incoming power wire) next to the wood, the wire on tho of that, and then the screw. So the resistance heating wire never directly contacts the wood. If you use similar materials, you must constantly watch out for unwanted heat!

With either commercial or home-built hot wire tools, you have to watch out for:

toxic fumes - Melting or burning plastic can produce toxic fumes. Always work outdoors, preferably when there is a breeze blowing away from your work. Our setup tends to minimize this problem by using a heat control. We use as lttle heat as posible.
burning and fire danger - The hot wire gets hot!
- don't burn youself
- don't cause a fire

guides and stencils
Cutting something freehand is a good way to get a wobbly result. If as all possible, guide your wire by running it along something. In the past, we have made arcs and circles by using:
- bottoms and tops of flower pots
- rim of a large stainless steel mixing bowl
- corrugated cardboard from under a pizza.
If your guide is cardboard, use the lowest heat possible that will still cut the foam, and move as fast as you can!
If your guide is metal, make sure that it doesn't short-circuit the power on your cutting tool.
For a smooth cut, keep moving! Don't stop and start. Don't do it in sections unless you have no choice.
When cutting fine details, get your hand as close to the work as safety allows.
Thought experiment: Think of picking up a felt-tip marker and writing your name on a tablet of paper. Now think about taking that marker to the end of a yardstick and writing again. You lose a lot of control being so far out.

Thank you for visiting. Your comments are welcome.
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