11 hobby knife and spare blades

Metal Parts from Papercraft Molds

This project began when I read the following entry [#274] in Volume 1 of Popular Mechanics’ 1913 The Boy Mechanic: The round lead weight for shot-putting or hammer throwing can be cast in a hollow cardboard or pressed-paper ball, sold in department and toy stores for 10 cents. Cut a 1/2-in. hole in the ball […]

Harvesting Chemicals from a Battery

This tutorial shows how to take apart a spent zinc-carbon dry cell of the common household type. Besides making for an interesting object lesson in electrochemistry, taking apart a spent D-cell, for instance, allows you to salvage many materials which can be of use to amateur chemists–materials which would otherwise probably end up in a […]