Two common methods of manufacturing cast stone: Dry tamp method and wet cast process. Both of these methods create a simulated natural cut stone look. The most common finish for a dry tamp cast stone is limestone or sandstone while the wet cast method is capable of providing a wider array of possible finishes.
Best way to describe Wet casting is like baking a cake. Where the tin is your mold and the concrete mix is the batter. Important considerations to wet casting: the current concrete mixture is essential and mold must be in perfect condition to prevent any leak in the mold which will cause discoloration and quality deterioration. The mold release is very important to prevent surface defect and to have the best surface finish results. Then cast stone must sit for so many hours to properly cure and strengthen before removing the molds.
On the other hand, dry tamp use hand tampered method where the dry concrete mix is hand tampered into the mold. This method gives the cast stone more of a refined and detailed look of limestone/ sandstone finish. Dry casting has faster demold time, and mold can be use several times a day, no treatment is required afterwards to achieved the limestone look, and repairs after demolding is relatively easy.
Dry tamp replicate a carved stone while wet cast looks like a molded product where details does now show as well as dry cast. Also, dry cast can only achieve limestone or sandstone texture and cannot create a smooth finish. Wet cast product is better when a structural product is needed and where bigger pieces need to span large opening.