If you would like to do this the simple way... Go to an auto parts store and buy some Blue Devil headgasket repair. It's actualy "water glass" or silica desolved in water and lye. mix it with sand in a mold so it's wet. When exposed to CO2 it will turn into a rock.
If you would like to do this the simple way... Go to an auto parts store and buy some Blue Devil headgasket repair. It's actualy "water glass" or silica desolved in water and lye. mix it with sand in a mold so it's wet. When exposed to CO2 it will turn into a rock.