Glass: Making the Mould

I began making the plaster and flint mould from the 3D print. Initially I thought that I could simply split the form exactly in the middle along the line between the two halves of the 3D print, however after making the first side of the mould, I realised this wouldn’t work as I tried to take the piece out of the mould and some of the edges broke off due to the slight undercuts of the form.

So I revise my idea and realised I would need to create a wavy line the ran exactly along the widest part of the piece dividing the mould in half along this line. This took a lot of time to find this centre line and involved looking at the piece through a closed eye and rotating it slowly to find where the form was widest at each point along the centre. Unfortunately however, the mould still broke a little at the edges when I tired to remove the piece, probably because the piece moved a bit when I tried to take the mould apart and due to how brittle the flint and plaster mix is together, it broke. In addition to this, amongst trying to work out how to make the mould work with the 3D print, I forgot about how the process of glass blowing into a mould works. You need to close the mould around the glass with a hole for the blowing pipe to go through so the blower can blow the glass out, this of course will leave a hole where the pipe has been. I plan to use this hole as the point at which the cable enters the glass and the point from which the glass hangs from, so I need that hole to be at the top of the piece. However, I had spit the object along the centre and therefore the only place the hole could be was somewhere along the centre.

Where the hole needs to be for the glass ( along the opening of the two half’s)


Where I want the hole to be so I can hang the piece from the top-


The way I decided I could get around this was to split the top piece of the mould, where I wanted the hole to be, into two parts so that you could close the top two parts around the glass and then bring them down onto the bottom half.

Top piece of mould is split in half and hole is in the middle. The two piece can be brought together around the blow pipe with the glass inside the bottom half of the mould-


Once the two piece are together around the blowing pipe and the glass, they can be brought down onto the bottom piece of the mould as if it was a two part mould-


Once the glass had been blow the top two piece come off together as if the mould was a two piece mould-


To fix the breaks in the mould I mixed up some plaster and flint and let it go medium hard and pasted it into lace. I then let it go hard and carved it back a bit so it was smooth ready to pour the new halves onto.

So I had to redo the top part of the mould again, this time making a pour hole at the top and splitting the top half of the piece into two sections. Below you can see a video of all the different stages of making from making the first half wrong to finishing pouring the two top sections. Hopefully this will work and will successfully come out of the mould okay.


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