Making a Plaster Mould

For my final rotation workshops I was set to do slip casting. Initially I was not really looking forward to this because I thought it would end up being a massive faff. However I did not find it a faff and I really enjoyed the actual slip casting.

The first and potentially most difficult thing to do was choose what object I wanted to make a mould of. I initially chose the three items below; an egg, a piece of an ammonite with iron pyrites on it and a scarab beetle.

I decided to use the egg but decided against using the fossil and scarab because I was worried about them getting damaged.

My egg, scarab and fossil.

Once I had chosen what I wanted to make a mould of, I made a clay block that would be level to the middle of my egg as shown below. I also made a funnel type shape so that there would be a space to pour the plaster.

My egg is almost ready to pour plaster onto, I just need to put the wooden slabs around it.
I put the wooden slabs around my object and I used some clay to seal everything so that none of the plaster leaks out when I pour it.
The next thing I did was mix the plaster. My main issue with this was that I mixed it for too long both times and so the plaster was a little too think each time.
I poured the plaster onto my object and clay and waited 20 minutes for it to set.
I took the clay off the sides once the plaster had set.
I took the sides off and ended up with this.
I used a surform to smooth the edges out so it fits together properly and looks tidier.
I used a coin to make some notches so that my mould would fit well and stay together.
Once I had my notches, I dusted off the mould and I used some soft soap to prepare it for putting the top layer on.
This is my two part mould, the top just needs smoothing out.
My finished mould ready to make slip casts. Unfortunately the top is a little messy due to me taking too long to mix the plaster but it should work just fine.



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