I seem to have been doing bits all over the place lately (walls, trees, plastic kits), so I am trying to tidy up the loose ends up and clear the bench a little. So first up is some retaining wall panels. Where my track leaves the mainline and heads down into the fiddle yard I wanted to have a scenic incline rather than have the track disappear into a tunnel and then start to decend. I have opted to have a retained wall, rather than a sloped bank cutting to save space and wanted to build the wall in brick. As there is quite a bit to do I have decided to make it from plaster rather than expensive plasitcard. So firstly I made a master mould from some brick embossed plasticard and scraps of mdf. It didn't need to be anything fancy, as long as the brick panel was square and flat. Once the glue was dried I sealed the mdf with some diluted PVA.
Then a two part silicone mould compound was mixed and poured into the master mould and left overnight to cure. As some of the retaining wall is alongside a curved track, it is nice to curve the wall panel slightly to match. This is easily done by packing out the centre of the mould to get a concave wall face or packing out the ends to get a convex wall face, as in the next picture.
Here are two curved panels. I have made the mould the height of the highest wall that I need, but if I only need a low wall panel I don't worry about completely filling the mould, as in the wall panel on the right. Once completely dry (usually takes a couple of days) the plaster panels are easily cut to size by scoring the back face and then snapping. The flat panels can be snapped over a steel rule flat on the bench, but a little more care is needed to do the curved ones. Expect to break your first attempt
Here's a flat panel. Banging the mould on the bench will help fill the mould and expell the bulk of the air bubbles. But I don't mind the odd random air bubble as it helps to make each panel unique and once painted will give the look of a chipped brick.
Here's a quick picture of the first few panels in place and given a quick coat of paint to add some colour. Once I have completed the entire length I will go back and add details and pick out individual bricks etc.