Before the moulds could be fired in the kiln, Becky removed the plastic from the outside (that we had used to make the moulds, as seen in previous posts, and the brick video). We then had to cover the sides and bottom of each mould with layers of scrim coated in plaster, to create a protective barrier to stop the plaster moulds falling apart in the kiln- four of us did this, and I didn’t take any photos as it was very messy! But you can see the moulds with their plaster coating in the above photos. The moulds then went into the kiln upside down, as you can see in the photos. They go in upside down so that as the mould is heated and the wax inside melts it will flow out of the mould, leaving empty spaces where the metal will then be poured.
The next step was to vacuum the insides of the moulds to ensure they were free of debris, ready for the pour. Once this had been done the moulds were ready to be winched into place using the pulley system in the foundry, and set up in the sandpit ready for the pour.
The video shows the technicians winching one of the moulds into place, I kept out of the way for this part as I hadn’t done it before and wanted to watch and make sure I knew how to do it for the next moulds. I then had to dig the moulds in, making sure the sand was packed in closely around each mould to ensure stability for the pour. To keep the moulds clear each one had a piece of wood placed over the top.
This was definitely one of the more arduous parts of the process- it took five of us to do the plaster coating, and four of us to get the moulds from the kiln into the sandpit, as each one was incredibly heavy and fragile. I was careful to follow all instructions from the technicians to make sure nothing went wrong!