25/01/2017 - WASTING PLASTER CAST AND LATEX

When I arrived in the workshop the next day after the second Sculpture session I picked up from where I left off and began work on my coke bottle centrepiece. First, we had to mix some fine casting plaster, instead of the much stronger Herculite we had been using in previous casts, and gently cover it in a layer around 2mm thick. Flicking it over the sculpture instead of pouring, so as to encourage as much of the plaster into the fine details as possible. The next step was to then mix another layer of plaster, this time with a coloured tint. Eventually when carving away the mould from the poured cast, this layer will be my indication of when I am almost through the other side.
Finally I added one final thicker white plaster layer to bulk out the mould and give it strength. Once all of these layers were fully dried I could then carefully remove the bottle and clay from inside, leaving me with a brittle mould of my initial sculpture. Although this method allowed me to have slight undercuts, there was some nipping around the top of the bottle which proved too much, and caused this section to break. Carefully, I was able to repair this with mod rock and some spare clay, however the fact this happened (along with my broken bee from earlier) really made me realise how effectively materials can be used to fix and work around problems as they arise.

Once all areas of the clay and bottle were removed, the mould dried and any holes or imperfections fixed, first I had to cover the entire inside of the mould with a few layers of sugar soap, a liquid agent which would help seperate between the casting plaster mould and the herculite cast. Once this was all dried, I could then mix the much stronger Herculite and pour it in. This would take a long while to dry, as now there were lots of layers of damp plaster all curing at once, so I needed to come back another day for the big reveal! The way this process unfolded as I gradually added layer upon layer to my project, all to create something which is ultimately of the same shape as I started with, was of particular interest to me. In ways it mimics the series of petrification processes which use layers of quickly accumulated sediment to preserve the forms of ancient organic matter.

Once I had worked on this cast as much as I physically could for the day, I turned my attention to my fossil carvings. As well as the plaster casts taken from these, I had taken care to also preserve the clay negatives as these in themselves had a nice aesthetic quality to them. There was still some latex left over from the session the day before. In lots of other peoples usage of the latex they painted a finished cast, which produced a brushed outer effect on the outside where a lot of detail was lost, however as I still had my clay negative carvings I thought I could use these to avoid the loss of detail, and have the inside edge smooth and preserving all details.

Adding each layer gradually, I ensured that all the minute details of my carvings were filled with latex without allowing it to pool and become difficult to dry evenly. I also ensured I was careful with painting to the edges of the carvings, so that when removed the latex layer would have a clean edge of even thickness. Once I had applied enough layers for the thickness I wanted and these were dried overnight for me to return to when I came back to break away my wasting cast.