Casting

I have spent the past 3 weeks creating clay figures, silicone moulds and resin models of birds. It has taken me quite a while due to time schedule for help from the tutors (as I was using materials and methods I had never used before) and I also came across a few obstacles during the process.

I decided to start producing models of birds to create a sculpture that will show movement hopefully similar to the patterns created during a murmuration. .

1. My first step was to create a shape of a bird that could be turned into a mould made out of silicone;

  • I decided to use clay due to the fact that it could be cleaned out of the mould after it had been made. I allowed it to dry out for 2 days making sure that the figurine was hard.

2. My next step was to turn the clay figurine into a mould using silicone;

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  • With the help of our university’s technician, Ryan, we created a perspex box which was taped up with masking tape to prevent the silicone leaking out of the box (also sealed up with plasticine as an extra precaution!)
  • This was when the FIRST problem occurred – the bird is glued on to the glue stick (seen in the photo) which is levitating roughly 1cm from the bottom of the box. The two wood bits across the top are glued to either side of the glue stick which are holding everything in place. However, due to the fact that the clay bird had not been put in a kiln and was just air dried clay (softens upon being wet) when the glue stick was glued to the belly of the bird, the dampness of the clay caused it to drop off… this happened when we were testing the height of the bird from the bottom of the box, and when it dropped a wing snapped off – due to this, i had to fix and reinforce the wings with more clay and super glue.

3. I left the silicone to set over night and the next day cleaned out most of the clay. However, someĀ of the clay wouldn’t come out as the figure was quite thin and detailed. The mould also formed air bubbles on the top of the bird which also allowed bits of clay to be stuck inside of these, this was due to the way the figure was sat in the silicone and the clay being slightly damp.

  • I decided to cast the first bird with plaster – this was so that the plaster would stick to the clay and pull it out of the small gaps. Unfortunately, the wings crumbled upon removal of the cast. From this point, to allow air to get out of the small parts of the figure, I drilled holes into the mould at the tip of the wings. However, this step helped to remove more, but not all, of the clay from the mould.

4. After drilling holes to allow more air to be pushed out of the moulds, the next material I cast with was resin;

  • As seen in the photograph above, this is the first bird that came out of the mould, by this point I had sculpted, sanded and painted the resin cast. I had to trim the size of the wings down on this model because one of the wings had not filled completely during the casting process. As seen above, air pockets formed in the wings which I tried to avoid the second time casting with Resin by drilling more and bigger holes into the mould.
  • After this resin cast came out, I noticed a chunk of clay stuck in the beak of the bird which was why there was only half a beak the first time casting….. (DUHHH)

5. Second resin cast! …

  • As shown in the photo above, the second time pulled off the rest of the clay and was almost the full shape (there was a loss of a wing tip and still a few noticeable air pockets).

I was originally going to cast the birds out of plaster due to financial problems and the ease of use with plaster. However after testing the mould with resin and seeing the final result of the cast, I have decided to cast the full set in resin.

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