Turntable continued

 Well, as I mentioned, I have to cover the gap between the ring rail base and the pit bottom. Plus, I have to make the pit bottom taper as the real one would have to facilitate drainage. So, I cut a sloped edge to some styrene plastic, sized to fit the base.

 This is how I will use it to screed the plaster as I put it in. In the event, it actually took multiple coats of plaster.

 I drew some circular lines to guide the plastic as I drew it around the ring.

 We are putting our first coat of plaster into place. I roughly shaped it with the plastic as I knew I would have to recoat this several times.

 Here is the big bucket of spackling compound purchased at Lowes. In O scale you go through lots of these buckets!

 Another view of the first coat. I wanted to seal up the gap as a first step.

 Again, using the plastic shaping tool. You can tell I get into my work.

This is a view of the whole pit after the first coat.