So today I had organised a meeting with Kostas, the tutor who specialises in 3D work. We had originally discussed creating a mould of my hands to represent people pushing through boundaries, which would be represented by the appearance and material of the final cast.
To begin this process we first used the laser cutter to create a box to hold the negative mould. We used MDF as it was sturdy and non-porous to hold both the moulding agent and the material used to create the positive casting. We cut a box using a base that was 250mm x 320mm. We set the speed to 9 and the power to 85. We cut four sides that fit on top of the base, creating a watertight seal with duct tape.
When we had created the box we were ready to start mixing the moulding agent. Alginate was the most ideal moulding agent to use as it is skin safe. It is commonly used in dental practises to make moulds of teeth. We had to work quickly with this material, as there was only 120 seconds from adding the water to the point where the agent would start to solidify.
We added 3 litres of water to 3 500g packs of alginate. When the water was added the mixture turned purple, after mixing it for a while it began to turn pink, which signified that the mixture was ready to use. As I poured it into the box I noticed that it had a bubbly texture and wondered what kind of effect that would create on the positive casting.
The particular kind of alginate we used was called Chromatic Alginate.
When the mixture sets it turns white, and becomes a similar consistency to tofu. It held its shape well when I removed my hands, and I was pleased with how the agent had captured the shape of my hands.
The next step in the process was to mix plaster of paris to create a positive casting from the negative mould. To do this we began to make a mixture using water and plaster powder. We began with half of a silicone bowl of water and added plaster powder until it no longer sank, the ratio was approximately 2 parts plaster to 1 part water. I mixed the powder into the water by breaking down all of the lumps and stirring it until it was the same consistency as paint.
After pouring the plaster into the negative mould I left it to set for twenty minutes. When this time had passed I cut the duct tape holding the box together so I was able to take the plaster and the mould out.
Unfortunately I had to break the alginate mould to take out the plaster cast. I was very impressed with the amount of detail that the alginate had captured; the wrinkles in my fingers, my fingernails and my fingerprints were all visible in the final cast. Due to the alginate mixture being bubbly in texture there were some bubbles visible on the surface of the hands and the background, however these were easily fixed or improved with the use of some sandpaper.
I was very pleased with the effect that both the alginate and the plaster had created. My fingers stood away from the background and I feel that this will work well in creating a webbing effect to make the hands look as if they are pushing against a flexible surface.
We decided to wait until tomorrow to use the cast to create a vacuum formed piece as the plaster was still warm and we didn’t want to break or deform it before it was fully set.
So, what went well?
- I am pleased the outcome of this session – I went into the session wanting to create a detailed cast of my hands to use as a model to create a vacuum formed piece. The result is definitely detailed and both Kostas and myself feel that it will work well in the vacuum forming machine.
- The level of detail in the casts is very high, this really enforces the element of humanity within the piece as it shows the cast was created from a person rather than sculpted from a piece of material. The more detail that is on the original cast the more detail the vacuum former will pick up, meaning that the vacuum formed piece should contain detail and texture. I feel that this will make it more engaging than a piece with a smooth, impersonal texture.
- This is the first time I have used casting to create a piece of work. I feel confident in the method and I feel that it is the right medium to use for this project. I also feel that now I know how to use moulding agents to create a cast I am able to be more creative with what I produce.
Even better if.
- I feel that if we knew more about the texture of alginate we could of perhaps made sure it contained less bubbles so that the texture of the plaster mould wasn’t so inhibiting of the detail, as some if it was obscured due to bubbles.
- As this was the first time doing this process it took more time than it usually would have. I feel that we could possibly have created multiple moulds if we had been more efficient with time, however this is something I will consider when I return tomorrow to make more moulds.
- I feel that due to the plaster being white and smooth the hands did not stand out enough from the background. It may be interesting to experiment with textures or to push my hands further into the mould so when they are cast they stand further away from the background. This is something I will think about during tomorrow’s session.
I am looking forward to tomorrows session and to continuing with this process as I really feel that it would create an interesting and conceptual final piece.