The work horse for earth plastering is these iron trowels, there the gigane, the g i g a n e trowels. There's also a blend after that call hanyaki h a n y a k i. The difference between those and the stainless ones are not meant for application. Each wall requires a different trowel. Practically o each layer that you apply requires a different blend of steel or iron or different metals. Cil holceder probably knows those things better than i do.