ROTO BLOG

Every metal tells a story. Sometimes it's obvious. A piece of lead feels heavy the moment you pick it up. A bismuth crystal announces itself with impossible colors and geometric shapes. Tin has a familiar brightness that craftsmen have recognized for generations. Other metals are far more reserved. An unlabeled ingot sitting on a shelf may have been purchased last year, or twenty years ago. A casting alloy might be exactly what the previous owner believes it to be. Then again, it might not. Ove …