Casting the jawbone raised a host of issues that I didn’t realise would be a problem, but hopefully it will work out in the end. Before we could make a hot rubber mould of the jawbone Becky (the technician) and I decided to make a plaster cast of the jaw, as we felt it would be too fragile to make a hot rubber mould from directly.
- Before we could begin casting I had to fill in the holes in the jaw (where the rest of the teeth originally were) with soft wax, so that it would be easier to cast. I also used a little superglue to secure the two teeth- we were worried that they may have come out of the jaw when we de-moulded it, so this was a preventative measure.
- I then pressed the jaw carefully into some clay and built up clay walls around it, and then applied a few layers of vegetable oil to the jaw to help release it from the mould once the alginate had set
- I mixed up a small amount of quick set alginate which I poured into the clay mould and left to set
- Once this had set I carefully removed the clay and rinsed the jaw and alginate, before greasing it up with more oil, and building up clay walls around it
- Another batch of quick set alginate was then poured over this, and left to set
- The clay was then removed, and the two halves of the mould separated and the jaw carefully removed.
- After cleaning both halves of the mould I fit them together and secured them with elastic bands, and was then ready to pour fine casting plaster into it
- The first attempt didn’t work very well and only the thickest section of the jaw came out, so for the second attempt after pouring in the plaster I moved the mould around to encourage the plaster to flow through the whole mould
- Once I opened the mould up I realised one half had not worked out, and the other half, where all the detail was, was too thin- to fix this I cut up scrim and layered that and some more plaster on top of it until it was thicker and stronger
- I then de-moulded it and created a hot rubber mould from that plaster cast. Because the detail was lost on one side I decided to make a flat mould, rather than a round one that needed to be cut open, to save materials
- The final photo on the slideshow is of the original jaw, first failed plaster cast, second plaster cast, and de-moulded wax cast of the jaw- as you can see there are a lot of details that need to be worked back into the wax by hand, but I am confident that it is doable
Photos of the wax casting process- melting the wax in a saucepan before leaving it to cool to pouring temperature (the wax needs to be cool enough that it coats the side of the pan), then pouring into the secured moulds, including the larger brick mould, before de-moulding and removing excess wax/working the details back in.
Video of two wax casts, fresh from the mould- you can see that there is excess wax that needs to be removed, and some of the details need to be worked back in to the casts.
Video made up of a clip showing the second, larger batch, of wax casts fresh from the moulds, followed by a clip of me working on one of these casts to remove excess wax and work a hole back into the cast to mimic the original bone. The final photo is of the wax cast from the previous clip next to the original bone I cast it from- you can see that I have worked some of the details lost during the hot rubber mould process back into the wax cast.
The two clips in this video show the first hollow wax cast of the brick I found on the river, and the second cast next to the original brick- you can see how the hot rubber mould picked up most of the detail from the brick, and how that has translated to the wax casts. You might notice some lines on the casts- this is because to make a hollow cast you need to pour in the wax slowly and roll the mould gently around to ensure the wax coats the mould properly- I did this too slowly so there are lines visible. Next time I use the mould I will be careful to pour the wax faster to avoid this happening- I may melt these two casts down and redo them. The brick casts need to be hollow as to make a solid bronze of that size would be too costly, and too heavy. I will either have to leave the hole in the bottom, or weld a small piece of metal over the hole, but this is something I will tackle when I get to that stage.
Unfortunately this was all I was able to get done before the workshops closed for the break, but I am looking forward to getting back into the foundry/plaster room and continuing my work! The plan is to make at least two of each bone in wax, and then make at 2 – 4 large moulds to go into the kiln and then be poured, as I want a copy of each bone in aluminium and in bronze. I have also been shown a material called glass wax, which is used in the film industry to make objects that mimic glass, and if I can afford it I would like to experiment with this medium as well, as it will give me another material and colour to analyse.
Whilst working on the burn out moulds that didn’t work I also decided to make a few batches of hot rubber moulds. The process is lengthier, but once the final plaster mould is fired in the kiln the waxes will melt out leaving hollow spaces for the molten metal to be poured into.
To start the rubber needs to be melted in the machine, by being fed into the top, and the press placed on top of it, using gravity to push it down to melt. It then drips out of the bottom into a bucket to be poured. Whilst it is melting I prepared the objects, by applying vegetable oil to each object for easier release from the moulds, then embedding them into clay, creating tunnels with the clay for objects that were going to be solid (although for the brick shown in the photos this was not necessary as I wanted it to be hollow and this required one side to pour in the wax). I then made a tube out of metal or plastic secured with duct tape, and pressed it into the clay bases around the objects. The tube then needed to be waterproofed with extra clay, ready for the melted rubber to be poured in. The next step was to pour the hot rubber into the moulds, and leave it to set. Once it was set I then made a basic plaster mix and poured this into the leftover space in the moulds of the bones (not the brick) to create a flat base for them to rest on.
When the plaster had set I then removed the metal/plastic tube and the clay from the moulds, and flipped them the right way up, using a craft knife as shown to make a few cuts into each mould, to allow me to remove the objects from the moulds. Once this was done they needed to be thoroughly washed to remove clay residue, and then secured with elastic bands or duct tape ready to pour the wax into.
The above video is of my “Unknown Landscapes” piece in the end of term pop up exhibition ‘Impromptu’ held in uni, with work from both first and second year students. I wasn’t involved in the set up of the exhibition so I had no idea the video works would be displayed like this, with each screen slightly delayed from the previous screen to create this effect- but I really like it and think it is really effective in showing off my work!
The images show my work at different stages on the screens, as well as shots of my classmates’ work. The exhibition was small but well curated and I feel that all the pieces worked well together in the space, despite being very different.
Our short film inspired by Jess Thom, BISCUIT, was projected onto the new hall of residence next to Camberwell College of Arts for the official opening night of the new building! This means it was potentially seen by everyone in attendance, including Jess Thom, the Dean of Camberwell, and Grayson Perry! The photo was taken by Jonathan and sent to our group, as we weren’t aware that it was happening on the night. There was no sound due to it being projected, but I’m very proud that our work was shown to such a large audience!