This short clip shows how I have been using an electric engraving tool to work details back into the surface of the brick wherever it was lost due to the casting process. The shiny parts are where I have used an angle grinder or Dremel tool previously to get rid of runners, risers, and other imperfections on the surface of the bronze. I have to take frequent breaks when using these tools, and swap hands often, as the vibration from the tool makes my wrists ache, but otherwise it is fairly simple to use. As always I follow safety protocol, wearing a visor, ear protection, dust mask, and gloves to protect myself, as well as having the extractor fan on and handling all tools safely and responsibly.
Once the moulds had been poured and removed from the sandpit they next stage was to cut off the plaster coating, with a saw, and then smash open each mould with a mallet. The above photo shows one of the bronze casts, mid smashing. The aim was to remove as much of the plaster as possible, which was then smashed and ground up into powder, to be reused for further mould making.
This video shows part of the clean up process- once the casts had been removed from the mould, the rest of the plaster still needed to be removed from around the casts. It has been sped up by about 250%, as the original video was 20 minutes long, and I wasn’t sure if anyone would want to watch it! As they were too big to be secured in a clamp at this point I had to secure them with pieces of brick, so that they were stable enough to use the hammer and chisel on.
Once I had gotten rid of as much plaster as possible with the hammer and chisel I tried to cut off some of the runners and risers using an angle grinder, which shook some more of the plaster loose. Before I could cut any more of the excess metal off I had to take them down to the print making studios and blast them with the pressure hose, not pictured because I got very wet!
Health and Safety: I had the extractor fan on, and wore gloves, a visor, ear protection, a dust mask and an apron
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!
I was worried that the process might be unclear from the step-by-step and photo posts, so whilst making the brick moulds in July I recorded video clips, as well as taking photos, to better showcase the lengthy process behind casting in metal in the foundry.
This video shows the process of putting the wax bricks into plaster moulds, ready to be fired in the kiln. This stage was the lengthiest part of the whole process, and shows at least 3 weeks worth of work in the foundry- whilst waiting for layers to dry I was also working on the wax bones and prepping those using the same process, to make the best use of my time.
Unfortunately some of the clips are poorer quality than others as they hadn’t automatically backed up on my Google Photos, so I had to download them from my Instagram instead. Going forwards I am going to be much more careful about backing up my documentation. I was also a bit under the weather at the time of recording the audio for this video, so I am a little bit breathy, and stumble on my words a bit, which I have tried my best to edit out. This is actually the 3rd attempt at making this video, as the first and second time it didn’t save properly, but 3rd time’s the charm!
On another note, I am deeply sad that Becky, the foundry technician, has moved to teach at Chelsea as we got on really well and she has helped me a LOT with this project. Good luck at Chelsea Becky, we’ll (I’ll) miss you!