For a diorama that im working on at the moment i needed a corner of a building. Normally i would have made this from foam board and plasticard, but because i wanted to do some specific damage results the foam card would be no good.
So i decided to have a go at casting some "walls" using normal plaster of paris. The idea that i came up with is to use the plaster sections as the basis for the wall and then build on top of them using my normal plasticard.
I've cast small things before, but nothing that required me to build my own mould nor that require perfectly flat edges, so i decided that it would be worth documenting the process from mould to final "wall"
The first thing that i did was to cut two squares in to a piece of PVC foam (if you havent seen PVC foam, its the same as Foam board but the card is replaced with plasticard). I then cut around the gaps in the PVC foam, and glued this new square to an even bigger square! Easier shown than described, especially at 2am! - Here a picture of what the final mould was:
Next i mixed up my plaster. I actually ended up doing this in two batches, as i wasnt sure what consistency to make the plaster.
The first batch that i mixed up was thick -about the consistency of yoghurt. It didnt flow well in to the corners and felt sort of 'lumpy' going in.
The second mix that i did was much runnier - about the consistency of thick milk. This flowed a lot better in to the gaps, although i did find that at lot of water ran to the top very quickly...
In the picture above, the top most mould has the thicker plaster, the one at the bottom has the thinner...
After about ten minutes, i scraped the top of each mould using a piece of thick plasticard. I then wiped down the edges and set the plaster aside to dry. So now the mould are sitting in the corner of the room drying. Ill post another update in the morning to let you all see how they turn out!