Making a plaster shield to be used as a cornice decoration

Over the last few years I have been embellishing the plaster cornice of a study with shields bearing the arms of institutions and bodies with which members of my family have an association. The number has gradually built up to produce a colourful and decorative display. The process of making one of these shields is shown below.

If a number of shields are to be made it is a lot easier to initially make a blank plaster shield with no charges on it. The necessary charges can then be moulded on the plaster blank using a modelling material such as 'Plasticine'. Fig. 1 shows the charges that represent the arms of the University of Birmingham modelled in 'Plasticine' on the plaster blank.

Fig. 1

This is then boxed in as shown in Fig. 2 below so that a mould can be made.

Fig. 2

If, as is the case here, the intention is to only make one or two copies the mould can be made using an alginate material, which is a non-reversible hydrocolloid and is relatively inexpensive. The alginate mould is shown in Fig. 3. If a large number of copies were to be made then a much more durable mould such as silicone rubber would be needed - and casting using this material is shown later.

Fig. 3

Fig. 4 shows the final casting after painting ready to take it's place on the ceiling cornice -

Fig. 4

- and Fig. 5 shows the shield in place together with the arms of Coventry University on the right.

Fig. 5

On the next page making a stone plaque depicting a coat of arms to be inset into a pillar.