If you’re reading Hackaday, there’s a good chance you had a rock tumbler in your younger days. Hell, we’d put odds on a few of you having one rumbling away in the background as you read this. They’re ...

Rust is the bane of any metal collector, whether they have a bounty of old coins or just an extensive wall of nuts and bolts for future projects. Once something rusts or corrodes, it loses its value ...