Your kind comments are really appreciated and I am having lots of fun playing with new techniques etc etc.
I know some of you are already expert at this but for me casting has always been a dark art. Having looked at a number of fantasy based sites I saw that casting paving floors, walls etc etc was very common. So although I don't know what I am going to do with this yet I thought I would give it a go, and provide a simple SBS for anyone who wants to try the same experiments. I decided to try to cast a section of rough stone wall.
Step one involved cutting a 1cm thick sheet of insulation foam, and then cutting it into rough stone shaped blocks. I sanded off the edges to give a worn look and stuck them together with white glue to form a basic wall. I then took a sharp knife and cut this in half along the long axis and stuck both halves to a piece of firm card, Step 2. This was given a coat of acrylic sealer and a thin coat of Gesso just to protect it.
I found some quick set silicone mould making putty in my local art store, Photo 4 shows the stuff I found. This comes in two parts, and like miliput etc you simply mix the two putties together to form the quick set moulding stuff. I smothered my rough wall with this mixture. Now this stuff takes about 10 minutes to set so you need to work fast.
After 10 minutes I peeled the mould off the original and voila! a rubbery mould ready to go. Step 5. I then made two casts from this mould the first in Hydrocal (like plaster of paris) and the second in quick set resin mix.
I think the result is very acceptable in both cases. The hydrocal version is probably cheaper to make than the two part resin mix.
I intend to continue casting these sections then to create some kind of house or castle etc by simply sticking them together maybe on a light cardboard backing. Notice that with the form I have made they fit together top to bottom, end to end and you can turn each casting in any direction so that the finished wall does not appear too repetetive.
I hope this is useful to someone.
John