If you require applying more that one layer of undercoat, to achieve your required thickness maybe two layer or more of undercoat is necessary. It is important that the second coat should be applied while the first is still damp but firm.
When mixing, add the plaster to the water in equal measures, using a clean bucket and clean water.
When the plaster is a creamy constituency pour it out onto the spot board (a piece of ply about 1m square) at a comfortable working height. Using the trowel scoop up and load the plaster onto your hawk before applying to the wall.