I'm making a slow combustion stove to put in my garage. It's an old design I half remembered from an old 1950s practical householder magazine. It a tube with a rotating ash pan that acts as a damper by covering a series of air holes at the bottom. Mine started life as an old c02 cylinder. It's a work in progress bit of a way to go but it's better than mouldering in the house tit deep in wrapping paper