Letter Re: Ammunition Storage and Do-It-Yourself Desiccants

Hi Jim.  
Dry wall is made of Gypsum, which is composed of Calcium Sulfate Dihydrate, with the chemical formula CaSO4·2H2O. It is found naturally and also made Synthetically by Flue Gas Desulfurization at some coal-fired electric power plants. Synthetic Gypsum can be used interchangeably with Natural Gypsum in some applications. There was a problem with drywall from China which contains too much Sulfur probably from the flue gas desulfurization process. When Water is absorbed by the bad drywall, Hydrogen Sulfide is formed which induces corrosion in some metals. I would not trust using drywall as a desiccant for ammo storage. Just think about opening your ammo boxes, finding the contents corroded! That would be "Penny wise and Pound foolish." – Chuck M. from the Northeast Kingdom