Not arguing with your preference for silica, but I find it impossible to believe that clay will not release water vapor when baked. I’ve seen an awful lot of clay suck up water when it rains, and then turn to dust in the sun.
“I find it impossible to believe that clay will not release water vapor when baked. I’ve seen an awful lot of clay suck up water when it rains, and then turn to dust in the sun.”
Me too, especially since I have commercially available desiccant bags filled with what I believe is bentonite clay and the instructions on each bag give a baking time and temperature to dry them out.
I wouldn’t use cat litter since it has perfumes which will make ammo smell like cat litter and might have other unwanted effects. Just buy desiccant bags, they aren’t super expensive: http://www.uline.com/BL_1001/Kraft-Bag-Clay-Desiccants