Making a Brass Model
a division of Sunset Models Inc.
16 Beta Court - San Ramon CA 94583
Phone: 925-820-7701 Fax:925-820-7709 

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How are Brass Models Made?

Castings: Master Pattern
3rd Rail engines are the highest quality brass models available today.  Hand worked brass is a tradition in the orient and expert craftsmen use every technique in working brass to create these works of art.  Lost Wax Castings are used for true, 3 dimensional scale details that cannot be obtained any other way. It is a labor intensive process where the mold is sacrificed for each piece produced.  There is no mass production. The process begins with a MASTER pattern.  This pattern is carved from any hard material, usually by hand into the desired shape and size of the part to cast. The master must be 104% of full size as 4% size is lost in the casting process.
Casting: Rubber Mold - Wax Copies
A rubber mold is made from a master pattern.  The mold is made of a special rubber compound. The rubber mold is filled with hot blue wax.  When the wax has hardened and is cool, it is gently removed from the mold and the mold is used again to make as many copies of the master that are needed to be casted. Special care must be taken that the wax does not deform as this will be reproduced later in the casting process.
Casting: Wax Tree
The blue wax masters are then gently assembled into trees. 
Casting: Plaster Mold
The blue wax master casting tree is placed in a metal can. A special plaster of paris is poured into the can, which is then vibrated to remove any bubbles.  The plaster is set to harden. Once hard it is removed from the can.
Casting: Molten Brass
A special mixture of metals, a closely guarded secret by the casting manufacturer, is melted with an Acetylene   torch.  The molten metal is placed in a centrifuge, with the molten metal near the center and the plaster mold at the other end.  When the centrifuge is turned on, the molten brass flows into the plaster mold, vaporizing the wax master and filling every nook and cranny inside the plaster mold.
Casting: Shattering Plaster
The hot plaster mold is then subjected to a cold water bath.  The plaster shatters from the hardened brass castings inside. 
Casting: Shattering Plaster
Further cleaning with a wire brush is required. Trimming and inspecting each casting is necessary for a finished product.
Etching: Boiler and Tenders
 Rivet detail, raised lines, door edges and wood textures are photo etched into brass sheets. The pattern for the photo etch is usually based on a CAD file generated at the factory. A photographic negative is used to focus a special light onto the brass, once a light sensitive chemical is applied.
Stamping: Boiler and Tenders
 Window openings, detail mounting holes are cut into brass sheets using a stamping tool. The tool is made specifically for the project and is made of soft steel. It can only be used for one project, then it becomes scrap metal.
Soldering: Boiler and Tenders
 After the brass is etched and stamped, the sheets are bent into tender bodies and rolled into boiler sections and soldered together by hand.  Castings and other detail parts are the attached with solder and screws to the main boiler and tender body parts.
Construction: Assembly
Finished castings are then assembled to other parts to make sub-assemblies.
Construction: Hundreds of parts
There are literally hundreds of parts to assemble and check. 
Construction: Prep for Painting
Once cleaned, the parts are sent to be painted.
Construction: Assembly
Once painted and decaled the parts are assembled into a locomotive, ready for final inspection.
Construction: Final Assembly
Chassis and boilers are joined and it is off to the test table.

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