Fire

Building a visco/cannon fuse machine for no reason.

A high temperature, insulating refractory exclusively from the hardware store at one-tenth the cost of and better than commercial firebricks or cer...

Simple, homemade electronic igniters from easy materials.

Making chlorates with electrochemistry is fairly easy. Perchlorates are quite a bit more troubling. Unless, of course, you just heat your chlorates...