When bronze or aluminium casting at SPACER, we employ the traditional ‘lost-wax’ process. The lost-wax process usually means that through our mould making and wax casting methods, we translate your original artwork into a wax. This wax is then encased in heat-resistant materials that set hard enough to create your ‘investment mould’. Your investment mould is then placed in our kiln and cooked for five days. During this time the wax evaporates from within your mould, leaving a cavity where your sculpture once was. It is in this cavity, that we pour the molten metal.
There are two methods that are commonly used to ‘invest’ waxes prior to cooking. The more modern method is called ‘ceramic shell’, however, here at SPACER, we use the traditional ‘grog and ludo’ method that was perfected during the Renaissance.

The Grog and Ludo Investment Method

First, an initial liquid layer made of herculite plaster and grog is applied to your wax, covering it entirely. These materials, in particular, have very fine particles, enabling them to capture fine details when set. After this initial layer of herculite and grog, the mould is completed using a less expensive investment material made up of fine casting plaster and ‘ludo’. We purposefully recycle materials as much as possible as part of our sustainability strategy. ‘Ludo’ is a recycled material from previously spent investment moulds, that have been crushed back down to a fine powder.

Grog and Ludo vs. Ceramic Shell

Many foundries now use the ceramic shell method for investment casting, which involves dipping your wax into a slurry made with ceramic powder. This is repeated a handful of times after each coat has dried. When thick enough, the mould can be cooked quickly. The wax is burnt out, and in the cavity remaining, the bronze is poured. It makes good commercial sense. It allows a much more ‘production line’ approach to casting, enabling a constant flow of investment moulds being prepared for the bronze pour.
However, we believe that this method consumes unnecessary amounts of energy. The investment material stored in tanks has to be continuously stirred automatically. This also comes with maintenance and equipment costs that are also not incurred with our grog and ludo method. Furthermore, the investment process for ceramic shell takes significantly longer.
Our versatile method allows waxes and other fragile and burnable assemblages to be invested within a matter of hours rather than days. This quick process can aid the casting of more experimental and fragile artwork. Although not the commercial choice, we believe it to be the creative one.

"For many, ‘Pour Day’ is the most exciting element of the entire bronze casting process. It involves a sense a tradition and ritual, as well as the hope that one’s artwork will pour well and that all the time already invested into casting the work into bronze will not have been wasted. Our foundry typically experiences a hushed silence during the pour; a healthy amount of fear and respect for the process and, usually at the end of the bronze pour, guests and students cheer - we suspect that this is out of relief that all went well." - The Secrets of Bronze Casting