Emergent Flock

transfigured wax to pewter

Iteration

Today I have been working on the deeper boxes - making moulds as well as casting and investing the waxes. In lost wax casting, the piece you want to produce in metal initially has to be cast in wax. Investing is the term used for the refractory mould that will then be cast around the waxes. It is into this investment mould that the molten metal is poured once the wax has been burnt out, leaving a cavity in the exact shape of the finished metal casting.

As If By Magic

The wax is exchanged for metal, shown here straight from the mould with some of the investment still stuck to the cast. The sprues, now also cast in metal, will be cut off and the remaining metal finished with sanding and polishing. This process is called 'chasing'. The two halves will then be hinged, ready to have the crows fitted.
The process of lost wax casting, also known as 'Cire Perdue' (or as it is now called in industry 'Investment Casting') is at least 4000years old, which makes my work part of a continuum that is difficult to grasp but feels important to be part of.

Investing the waxes

Here are the waxes for 2 boxes, sprued and part invested. Investing is the sacrificial mould made around the wax - it needs to be made of a refractory material that can withstand the temperatures involved in the casting process. As these pieces will be cast in pewter, plain Plaster of Paris is sufficent, For bronze, however, I would use ceramic shell, a much more exotic material but one that can withstand the thermal shock of molten iron at around 1500c.
Once the waxes have been fully invested, they will have the wax melted out prior to being baked for 8 hours to burn out the residue and dry the moulds. They will then be ready for casting tomorow.

A flock of Crow waxes

Here are the completed waxes for the murder of crows boxes. These are to prototype the new simpler crow lofting mechanism. They just need to be sprued and then they are ready for investing, prior to de-waxing and casting in pewter.
A flock of crows in a box the size of an expensive mobile phone!

Begining The murder of crows

Today's post is the plaster mould, taken from a clay master, of the box for the murder of crows.
This mould will then be used to cast the box in wax, which will be used to cast the finished box in pewter or bronze.

Fresh Pewter Castings

Shown above are 3 castings of prototypes for the pocket divinity, 2 of which have 'flashing'.
This is a casting fault which is caused by cracking of the mould and subsequent molten metal running into those cracks. On occasion this can produce striking serendipitous effects but, as can be seen in prototype on the left of the photograph, at other times the effect is less desirable. In this case, the metal will be melted and recycled.

Creative process

As this blog progresses and, because it will be a sculpture a day, I will document the creative method. This will inform the reader of the process involved in taking an idea and turning that into a piece of metal art. It is a long and involved process and I consider my approach, with respect to other sculptors, as unusual in that I actually carry out each step my self. I have my own foundry and so am able to cast my own work, resulting in a sense of artistic control at each point. Today's image is of me pouring molten bronze at around 1200 centigrade.