Wall filler is used extensively in our models to give texture, strength and detail to buildings. This is Salvatore's SAM Station project. In this section, Salvatore explains how he uses filler.
Filler is one of those materials that goes by different names in different countries. In the UK we just call it 'wall filler' or use the most common commercial name, Polyfilla. In the USA it is often called 'spackle', 'spackle compound' or 'joint compound'. What we are referring to is the white powder, bought in hardware, DIY or decorating stores, that you mix with water to form a paste. It is used to fill cracks in walls and dries to a hard white plaster-like finish. Some types come ready mixed in a tub.
Thin the filler with water prior to application (only a very small amount of water is needed). Once thinned, sand may me added for a rougher surface. The look of concrete can be created with a few drops of black India ink mixed into the filler. The result will be a beautiful gray finish that requires no painting except for highlighting. An adobe-style finish can be accomplished in the same manner by using tan ink. Check your local art supply store for a wide assortment of colors. The more expensive the ink, the deeper the color. If you choose to color the filler with ink, add a little PVA to the mixture so you don't have to seal it for strength later. If you coat a finished project that has tinted filler with PVA, you will kill the effect.
The basic tools for applying filler are a bristle brush, foam brush, or a putty knife. The tool combined with technique will determine the character of your finish. Careful application with a foam brush or putty knife produces a smooth surface. Haphazard application with a bristle brush produces a rougher surface. Another technique includes applying the filler and texturing with a sea sponge.
Filler takes a full 24 hours to cure properly. Sand with a fine grit, if necessary, and seal the project with thinned PVA for durability (if the filler is not already pre-tinted with ink). A popular method for painting involves undercoating with black and dry-brushing with successively lighter shades. You can coat the project with matte spray (Testors 'lusterless' is one favorite) for extra protection and contrast enhancement.
Once dry you can sand, drill and carve filler to produce a variety of effects. This castle tower was made by covering a cardboard tube with filler and then the brick pattern was etched into the surface. Applying PVA glue to the dried filler will greatly increase its toughness. Do the carving first though - the PVA makes carving extremely hard work. For more details of the castle project refer to the buildings section.
We also use plaster of Paris in some models, such as the Lizardmen temple. Plaster of Paris is Gypsum - the stuff that they put on broken arms and legs.
It is much thinner (more runny) than wall filler, which makes it ideal for casting details such as the glyph plates on the Lizardmen temple. The temple was also coated with several layers of plaster of Paris. This produces a smoother finish than wall filler, and being thinner it runs into all the details and doesn't obscure them like a thicker coat of wall filler would.