WOOHOO! Good weather = time to build

[doctorwayne]

Tom and DocWayne, the water looks pretty flat, no ripples. To obtain that look, do I need to use a "self-leveling" method like the EZ water? That would mean plaster abutements. DocWayne, could I get the flatness by your method?

Now, on the plaster, it would be pretty cool to form the abutements with styrene, insert the pipes, and then pour the plaster in.

You could probably get the water flat enough using Durabond, as the channel is fairly narrow, allowing you to rest the edges of the finishing knife on the banks. It's unlikely you'll be placing your camera on the "water", so any irregularities could be smoothed with drywall mud. Durabond cures rock-hard and is difficult to sand, although when first set, it can be scraped flat fairly easily, especially on a narrow area. Another option would be to mix the Durabond very thin (lots of water). It would then be self-levelling, although would take perhaps longer than usual to fully cure. It seems to set in the time stated on the packaging, regardless of how much water is used, though.
For forming the abutments and pier footings, a styrene mould is a good choice if you want to pour them in plaster. There's some more info HERE and even though it shows free-standing moulds, the techniques for ones in-place on the layout should be similar. If you pour around pipes, you may find that the plaster will form a meniscus around each pipe: as soon as the plaster sets firm, strip off the mould and use a knife or other suitable tool to dress the top surface of the plaster and remove any unwanted "creep". The Durabond is quite carveable at this stage. If you get air bubbles in the moulded surfaces, simply mix a small amount of material and patch as required.

Wayne