Running of a Reverse Cornice Mould

Running out a reverse cornice is the same as running out a panel mould. There are only two differences; the setting up and a larger template is used. Because of the size of the mould, it is possible that a large swell in the plaster might appear, so a false template called a muffle is used. A piece of old plaster moulds or plasterboard can be fixed to the bench with nails to save plaster. To hold the core in place, canvas or hessian is soaked in plaster and layed over it. The core can be nailed to the bench because the reverse mould may need to stay there. The mixing for this mould will need to be done in a bucket because it is a bigger moulding. The plaster can then be poured and the could can be run across the core to make the muffle the correct shape. Take the old muffle off, check the template to make sure there is no damage and then clean the mould once the run has been completed. A craft should be used to make a deep criss cross key in the core. The bench, rule and mould then need to be re-greased and you can run out until you get the finish you need. The ends of the moulding should be squared off to the length needed once the plaster has set. Once the moulding has completely dried, three coats of shellac should then be applied.