So its now the morning, and the plaster appears to have set, so i set about popping the plaster from its mould... And hit on the first problem! It would seem that both of the mixes that i used were slightly the wrong consistency.
The thicker consistency plaster doesnt look like it set properly, whilst the thinner plaster had an odd "oily" texture to it (it felt wet, but in a very odd way - the same way that olive oil feels!). Here is a picture of the two plasters still in the mould
You can clearly see how the thicker plaster has become lumpy. The thinner mix looked a lot better, just some small amounts of shrinkage around the edges.
I flexed the mould slightly to release the plaster and immediately found a problem with the thinner plaster - it cracked!
After popping out the thinner plaster, i then moved on to the thicker mixed wall - and again it cracked. I was left with two broken walls!
After cleaning up the thicker wall (the thinner one didnt seem to need it), I was left with the four major sections. As a first go at casting, they are not too bad. I dont think they are good enough for the main walls for the diorama tho, Im not sure that they have the structural integrity that i need, but not to worry they will be recycled for use as small parts of masonry or possibly part of the upper level!
So now i'm back off in to the kitchen to mix up some more plaster and retry my moulds... More updates to follow