Write an article based on this "Draw a centerline on your master part. Embed half of the master item in a clay bed. Attach 4 alignment keys to the top of the clay bed. Secure the master part to a retaining wall. Cover the master item’s exposed half with silicone mold putty. Attach a second retaining wall. Create a durable mother shell. Remove the retaining walls and clay bed. Create the second half of the 2 part mold. Remove the master part from the mold."
The separate sides of a two-part mold join along the centerline of the master object. Retrieve your master item, a permanent marker, and a ruler. Draw a straight centerline around your master item. Set a block of non-toxic and non-drying molding clay on your work surface. Embed the master item into the clay up to the centerline. The top of the item should line up with the top of the clay bed. There should be a 1 inch border of clay surrounding the remaining 3 sides of the item. Alignment keys join the 2 halves together perfectly. Retrieve four ½ inch alignment keys and a bottle of temporary adhesive. Apply a thin layer of temporary adhesive to the flat side of the alignment key. Place the key in ¼ inch from the top left corner and adhere it directly to the clay. Place 1 key in each of the remaining 3 corners. In order to fill the mold, you must provide an opening. For this mold, the opening will appear at the top of the clay bed. Apply a thin layer of temporary adhesive over the top of the master item—the side not embedded in clay—and the top side of the clay bed (the side directly below the top of the master item). Press this side flush against a wooden or metal retaining wall. Allow it to dry. A layer of silicone mold putty will form 1 of the mold’s inner walls. Coat the master part with a release agent. Apply a layer of mold putty to the exposed half of the master item. Apply mold putty to the clay bed’s surface, carefully covering the alignment keys. Extend the molding putty ½ inch up the retaining wall. Apply a thin layer of temporary adhesive to the bottom side of the clay bed (the side parallel to the top of the master item). Press this side flush against a wooden or metal retaining wall. Allow the adhesive and the molding putty to cure for 1 hour. Due to the flexibility of cured molding putty, it is necessary to create a second more durable shell, known as a mother shell. You will create the mother shell with plaster sheets.  Cut 4 to 6 sheets of plasters. Each sheet should be 6 inches longer than the mold. Layer the sheets on top of eachother.  Dip the sheets in bowl filled with room temperature water for 1 second. Remove the excess water by squeezing the sheets over the bowl. The sheets should be wet, not dripping with water. Lay the sheets over the mold and up the retaining walls. Press the sheets into the mold so that they form to the shape. Crease the edges along the retaining walls into crisp 90° angles—the plaster sheets lining the retaining walls will serve as feet.  Allow the plaster to cure for 30 minutes. Once the plaster has hardened, remove the two retaining walls. Flip the entire mold over so that it is resting on the 2 plaster feet. Carefully remove the clay bed and any remnants remaining on the master part. If the key alignments do not come off with the clay bed, remove these as well. When creating the second half of the 2 part mold, you will repeat the process you just completed:  Apply a release agent to the master part. Attach the top of the mold to a retaining wall. Coat the master part in a layer of molding putty. Attach the bottom of the mold to a retaining wall. Create a mother shell out of plaster sheets. Once the plaster has cured for 30 minutes, you can safely disassemble the mold. Remove the two retaining walls from the mold. Place the mold upside down on your workspace. Remove the mother shell and carefully peel away the silicone mold. Set aside the master part and reassemble the mold.