Method: The Art of Casting
How we make Bronze & Sterling Silver
We start with a method you may have heard of called ‘Lost Wax’, which is the best way to pick up fine detail such as the little lines and crevices of your baby’s feet.
We use a gentle casting mousse called alginate to make the mould of your baby’s foot and this is beginning of our process.
An extremely hot layer of wax is "swished" around the mould, capturing every detail.
Cooler layers are then added making the wax thicker and stronger until a perfect shell is formed - similar to that of an Easter egg.
When the wax has fully set it can be popped out of its mould and any imperfections such as air bubbles or little bumps are made perfect and any fine detail lost in the process so far is replaced.
The cast is then attached to a holding device formed out of wax and wire, called a ‘tree’ (above right).
This is now sunk into a flask of investment material – a liquid which sets a bit like plaster.
When set, the foot goes into a furnace where the wax is melted out (hence ‘lost’) and the mould is ready to be filled with metal (bronze or silver).
The molten metal is poured very carefully into the mould. It is hotter than boiling water so all measures are taken to keep it under control.
The container holding the bronze is called a ‘crucible’.
Once they have been filled with the bronze they are left to cool. You can see here the ones that have cooled down already by the dark grey colour.
When they have set they can be hammered out of the investment material to reveal the metal underneath.
Now it needs to be ‘chased’ which is the word for finishing metal. For this, they go onto Heinrich, an experienced ‘chaser’ (and patinater).
The bronze (or silver) needs to be made perfect using specialist drill attachments and hand tools. There will be bubbles and small imperfections that need to be removed and sometimes a bit of detail needs replacing. It can take up to a day or more to chase a pair of feet.
Finally, the casts will be polished or patinated.
Patinating is the word used for ‘colouring’ bronze. Patination is achieved using certain chemicals which are painted onto the casts and then heated with a blow torch to cause a chemical reaction until the desired colours are reached.
We try to achieve a warm golden patination or polish the bronzes (highly polished) but a verdigree and other colours can be made depending on the chemicals and techniques used. It is a skill that takes much time to master and is an art in itself.
If you have chosen a highly polished finish for your bronzes (or silver) they will be polished on a machine (see above) until they are super shiny and lovely!