Change of plans:
During last week’s lecture, Professor Marcela brought up how milk plastic was already used before in order to make various beads and buttons. Initially, I was planning to make a cup holder out of milk plastic. However, I started to realise how much milk I would actually need in order to make one cup holder.
From previous experiments, I realised that a lot of milk was needed in order to obtain a small amount of casein. My previous experiments, using 500ml milk, resulted in not even half the amount of casein I needed in order to make one cup holder. To make one cup holder, I would then have to use at least 1 litre of milk along with 16 tablespoons of vinegar. This does not include the casein that would crumble off during the moulding process, a situation that often reduced the initial amount of casein even further. When applied to the real-world situation, no one would ever continually use litres and litres of milk just to make a few cup holders that would be discarded after one use. This would be unrealistic and continuing with cup holders would be an inefficient waste of time and effort on my part as well.
Hence, with this in mind, I decided to change what I was going to do with my milk casein plastic experiments. Yet, I didn’t want to make small decorations or trinkets with these milk plastics as I wanted to try to contribute to solutions for more sustainable disposable items that we often use. Even though single-use plastics are extremely detrimental to the environment, it would be idealistic to believe that everyone would completely stop using them as they are simply too convenient.
From various lectures and research, I learned how there are different types of plastic in a single plastic bottle. The actual plastic bottle is able to be recycled as it is type 1 PET plastic. However, the bottle caps are not able to recycled and discarded. As there are as many bottle caps as there are bottles — this still creates tons of plastic waste. Due to the bottle caps small size, I decided that this would be a better product to use with milk plastic. Bottle caps are still a disposable product that is often used once and never again. From this information and small size, I decided to try to make bottle caps out of milk plastic.
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Hypothesis: Can milk plastic be moulded to usable bottle caps?
I started googling some methods on how bottle caps were made. Unfortunately, since many people don’t make bottle caps, the majority of the search results were how to recycle bottle caps. Whilst interesting, these were not helpful. I just hoped for the best, using actual bottles as the mould and started my experiment.
Using the original procedure from the last 2 experiments, I heated milk, added vinegar, squeezed out the liquid and started moulding the milk plastic onto a plastic bottle. This proved to be much trickier than I expected. At first, I the milk casein dough kept cracking and breaking off due to how small and wide the opening of the bottle was. Due to this, I decided to switch to a milk carton as the hold was smaller in width but taller in height, which allowed a more solid base for the bottle cap.
After some careful moulding and smoothing out the cracks, using some skills I used from a previous pottery class, I moulded the milk casein onto the opening. As I had extra milk casein, I tried to experiment with an alternative bottle cap, a kind of plug that is often used in wine bottles.
Results:
After about a day and a half of drying, I attempted to take the milk plastic off of the mould. It was able to be taken off and kept the mould of a bottle cap. However, in the process of taking it off, some cracks deepened and tore.
On the other hand, the alternative bottle cap plug failed as it shrunk. Also, texture was too hard and not ‘squishy’ enough to be a sufficient bottle plug.
Reflection & Next Steps:
Although the bottle cap tore a bit when I took it off the mould, it generally worked quite well as a bottle cap with gentle twisting and tugging. However, it is still quite fragile as a bottle cap.
The bottle cap plug was a fail and the milk casein texture is not suitable for a bottle plug, so I wouldn’t be continuing to experiment on this.
For the next steps, I will wait longer than 2 days before attempting to take off the bottle cap in order to give the milk casein more time to dry and harden and I will also try to mould the milk casein more evenly onto the mould. Both of these would hopefully reduce the likelihood of cracking and breaking.
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