Let us start right out with … I am a total newb when it comes to casting with plaster, etc. There.  That said, the following is a look at how I made the core of my pit wall for my diorama.

Building the form.  I made a rough outline of the slate pieces from the previous work on the black faux marble piece I am using for the base.  Then using that I roughed out what the real pit wall was going be shaped.

Like the picture in my previous post indicates I wanted a concave corner of the wall.  Which should have turned out like this:

The form layout in red with two half inch dowels for vertical support of the platform.

With the above structure in mind and plenty of materials to build the form with, here’s a look at the form pre-use.

See that gap at the bottom of the foam?  Yeah.

An attempt to fill that gap and added support at the top.

Added the minis to give a sense of scale.

The bottom of the whole thing is super glued to the acetate sheet.  With luck I filled the gaps enough between clay and glue to prevent seeping.

So, for the first time ever, I mixed some dental stone.  This dental stone is supplied by a dental appliance lab nearby thanks to my stepfather who is a dental technician and builds dentures daily.

The bulk package I got from him was simply a zip-locked bag of dental stone placed inside a second zip-locked bag to prevent moisture I would assume.  No instructions aside from verbal.  Sift the mix into some water until the stuff doesn’t instantly drop into the water.  That seemed kind of archaic and cryptic like a master instructing an apprentice back in the day.  I was expecting … add X grams of mix to X grams of water or some similar scientific ratio.

So I grabbed 2/3 cup of water added it to a soup take out container my fiancée picked up at a supply store.  She uses them for holding her piping bags open while she fills them with frosting she mixed in a bowl..  Then I slowly added the mix sifting it from a paper plate I bent to form a “V.”  And mixing every so often with a popsicle stick, sure enough the water stopped absorbing the mix.  A final careful stir to keep bubbles down and I was ready.

Now, considering I hadn’t bothered to calculate the volume of mix/water I would need for this specific application … okay I was totally eyeballing the whole process.  The amount I made filled the form to the top almost exactly.

And then the spot I missed in the foam/acetate barricade started seeping out.  Which looked like this:

I lost about 3/4s of an inch from the top.  🙁

Luckily with some quick clay mashing and the setting of the mix it stopped.  So I mixed a second batch and topped it off.  Unfortunately, my estimating skills for this batch were off and I ended up with an old ice cube tray of blocks.  Figured I could use them for something.

And of course, I had to check it out before I went to bed.  My second mix was a little “wet” apparently as I still lost some height to settling.  The first pour really was close to spot on.  There was less than an 1/8 inch of water on top after curing.

As you can see, I still ended up with some lost height:

Say hello to my Lego cheese wedge.

I put the block on the base for comparison.  The gold line just in front of the wedge is the stairs platform that will be above it.  The one closer is the stone where the summons will be.

To that, I talked it out with my son and to maintain use of the minis in the display, I am going to shoot for keeping them modular.  That said, the stone I had in place will be out.  I am going to make MetalChaos’ clay golem/carnage demon conversion at this point.  Include the summons circle in the base of the demon and then sculpt the base into the display piece and leave it removable.

I am also looking at making the Blood Lich and his altar removable.  We’ll see what I can work out when I get to that stage of this build.

Next for the Pit Wall:

• Cut off the excess dowel on the pit wall. 
• Sand the top smooth
• Sand and carve out some of the pit wall face to get it back towards concave.  If I can leave in some details that look good, great.
• Add sculpting material back to the pit wall to get rock details. (see rock face stamps below).

I will also continue working on the various pieces concurrently so don’t be surprised to see me jump around on my posts.

Rock Face Stamps: