There’s everything from a table of design requirements to quick but thorough explanations of nichrome wire and basic electronic theory. And then there’s the material consideration.

While there are all sorts of ways to build a hot wire foam cutter, this design from [jasonwinfieldnz] is both interesting and imitable. If you don’t already know it, nichrome wire is nifty stuff ...

When a length of copper or nichrome is heated, it lengthens due to thermal expansion. The wire is suspended between two posts and heated by a variac. A small weighted hook is placed in the middle of ...