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Progress, Volume VIII, Issue 2, 1 October 1912, Page 101

About the Home

The Bronze Bust of the Late T. E. Taylor, Esq.

We illustrate a life-size bust of the late Thomas E. Taylor, Esq., which was recently cast in Wellington from moulds made by Mr. Joseph Ellis, Modelling Master at the Technical School. The bust was cast by what is known as the “A Cire-perdue,” or lost wax process. This method has at least two advantages over casting in sand, inasmuch as the artist can work on the wax model after it is taken from the piece-mould and re-touch any part of the model which may have been damaged during the casting process. This is the second and perhaps greater advantage, especially in work in the —that there is no cutting up of the original model into many parts and subsequent

joining and bracing together, no matter how intricate the model may he, it is possible to mould and cast 'it in metal by the lost-wax method. How exciting and what anxious work the casting itself is, has been described by Benvenuto Cellini, when he cast his statue of Perseus. Cellini and his contemporaries adopted the wax method when they wished to reproduce their models in bronze, and there seems to be no doubt but that this process, so much used by the Italians is the best way of converting into bronze a model which has many intricacies, much undercutting or free places pieces projecting from the model. We will give a summary of bronze casting by the

"A Cire-perdue" method, which may make it easier to understand its possibilities: In the first place a bust or figure is modelled in clay and a plaster of Paris or gellatine mould is made, from the finished bust. This impression is then filled with plaster, and when it has set the outer shell is removed. The next operation is the making of a piece-mould from the plaster model, so that the different parts may be removed; the pieces are fixed in an outer case and covered with a liquid wax to the required thickness, for it has to be remembered that the place of the wax will afterwards be taken by the metal. Before the wax cast is taken from the piecemould it is filled with a' special composition of brick dust and plaster made to a paste consistency with water; this forms the "core" or model of the inside

of the wax cast; it also serves to support the wax and prevent it from twisting, as the “core” is built over an iron armature. When the brick-dust composition has become sufficiently set, the outside mould is taken away and the sculptor proceeds to remodel any parts which may have been damaged during the casting; especially where the mould has left seams at the joints. When the wax model has been touched up, it is necessary to insert small rods of bronze through the wax into the “core,” and to let them stand out in order to join the outer model to the “core,” and so sustain the latter in place when the wax form has been melted.

A few "ducts" are inserted for the outflow of the wax, which does not get absorbed by the mould and "core"; also "vents" for the escape of air during the casting; wax tapers are usually employed for this purpose, and lastly, the "ingates," through which the liquid metal is to flow into the mould. Then the figure is covered by a carefully prepared mixture of clay, brick-dust and plaster, laid on in several layers, and bound with iron bands so as to form a strong shell. When thoroughly dry the whole is placed in the casting pit and through the application of continuous heat the wax is melted and driven out of the prepared channels. Part of it, however, is absorbed by the mould and "core," and helps to strengthen them. Next the mould 'is packed all round with sand to hold it firm, when the metal is being poured. When the mould is sufficiently cool it is filled with the molten metal, and, if no accidents occur, the metal will rise and fill all the parts left vacant by the wax. When the metal has cooled the outer shell and core are removed and the casting exposed with its pins, ducts, air jets, and runners ; these are trimmed with saws and chisels. The work is then cleaned in a weak bath o± sulphuric acid ; and eventually in a bath of clean water. The final touching up is done with small chisels, riffles and scrapers. It may be mentioned that this is the first work of art in the round that has been cast in New Zealand by the lost-wax process. The clay model for Mr. Taylor's bust was made by Mr. Mansfield, of Christchurch, and the metal mixing and pouring by Mr. George Stewardson, of Wellington, to whom the commission of casting the bust was entrusted. The photographs were taken bv our Mr C M West. "