Here's a photo of the essentials for a layout. Clay from Walmart. Blackboard Chalk. This will last for years, Take piece and rub it on a coarse file into a little tin container to make a fine powder. Just dab your finger in it and dab on to the metal, after rolling the clay over the surface you want to draw on. The clay leaves a slightly greesy surface that the chalk sticks to. A good mechanical pencil, I like Pentel 0.05 some fine sandpaper to sharpen the lead. Transfer paper from Tandy Leather Co. and your model to work from.