PROJECTS: ST YRO CU T TER
THE CUTTING EDGE
EPS is a thermoplastic foam that can be cut with a hot
wire like a warm knife through butter.
You can buy expensive, commercially made hot-wire
cutters, but I’ll show you how to build a super-simple DIY
design quickly for next to nothing, and how to get great
results with some clever accessories and foolproof techniques.
For the cutting wire, this design uses a fine wire made of
nichrome (nickel-chromium). It’s held vertically on a table
and kept taut by a bent aluminum arm. A model train
transformer is used to convert AC power into a controllable
and safe 12 volts DC. As the current passes through the
wire, it warms up. This design lets you guide the pieces of
foam into the stationary wire and slide the foam around to
make effortless cuts.
HOT-WIRE CUTTER EXPOSED
This cross-section view shows
how the conductive aluminum rod
completes the circuit to provide
current to the nichrome wire.
To make perfect cuts, use cutout
cardboard shapes as templates.
1 Nichrome wire
2 Aluminum rod
2× 4 base
4 Wire anchor
6 Red test lead — positive
7 Green test lead — negative
9 EPS foam
Illustration by Bill Oetinger
116 Make: Volume