Carlos, Plaster is a name for any plastic material that hardens in place. It is a type of composite (aggregate needed). You would need Calcium Carbonate (lime) and an aggregate (binder). You would need burnt lime to start you would then hydrate with water. This makes it pliable and consistent. You would also need to add an aggregate. You could use horse hair, stones (sand), etc. These act as the binder of the plaster. After it is mixed it can be worked. It is then starts to harden afterwards. If you use sharp textured sand (almost microscopic) it it more durable but harder to work, smoother sand less durable but easier to work. A combination is good.
Attach lath to your framing, (small wooden strips) and then apply the plaster with a trowel. You need several different layers. Starting with a rough etched layer and proceeding to a fine finish. The plaster protrudes through the lath, hardens and mechanically binds itself.
Disclaimer:
I am no plasterer. However I know some. I had to recite from old notes. Plaster is a material that takes time to work the right way. I don't have any ratios for the mix. If you do intend to use plaster, I can get you some more specific information via email. let me know. By the way Calcium Carbonate (limestone) is all over the world (dead sea life).
