Producing Plaster Components Casting a plaster slab

Casting a plaster slab Tools and materials required for casting a plaster slab  Class A Casting Plaster  Canvas Hessian  Oil  Mixing Bowl  Builders Square  Pre Greased Timber Laths  Pre Soaked Timber Laths  Joint rule  Scissors

Casting a plaster slab The timber bearers are secured into place Timber bearers for a plain faced cast should be at least 30mm x 30mm

Casting a plaster slab These will be the strike offs, the finished levels for the plaster slab Using the pre cut,and pre greased timber laths and a builders square check for accuracy prior to screwing to the bench

Casting a plaster slab To prevent the plaster slab from sticking to the bench, it is coated with a layer of vegetable oil, and allowed to dry. This is know as a release agent

Casting a plaster slab Once the plaster has been mixed to a creamy consistency the firstings are poured into the centre of the cast and allowed to disperse.

Casting a plaster slab Using a joint rule make sure that all the surface area is covered

Casting a plaster slab When the firsting have started to set it is time to install the reinforcement For this we are using timber laths that have been pre soaked for up to 24 hours

Casting a plaster slab The reason for the pre- soak is to allow for the timber to swell twist and warp. The timber laths are laid parallel to the strike off Canvas hessian is cut to size and used to provide strength to the slab

Casting a plaster slab The seconds are mixed and spread with a joint rule over the timber laths. The strike off points are kept level to the timber fence.

Casting a plaster slab Once the strike off are filled level, they are cleaned off with clean water. A light splash of plaster onto canvas hessian to secure it into place

Casting a plaster slab Once the plaster slab has set and all the heat died off,it is time to remove the timber bearers.

Casting a plaster slab The completed plaster slab. Any imperfections can be cleaned off with either a busk or joint rule. Then put in a safe dry location to dry before it can be installed