Bronze Bath Casting From concept to final product, there are many hours invested in producing a bronze bathtub. These unique baths are created by artisans, using time tested old world techniques. Read further to learn all the steps involved in the production of these magnificent baths. Manufacturing Process: 1- Design (Adapting the design to sand casting process) 2- Pattern Making 3- Molding 4- Casting 5- Mold Clearance 6- Polishing 1- DESIGN The design should be adapted to the sand casting process. The wall thickness, radii, height, edges, angles, slopes, etc. must allow the producer to make the soundest casting. Therefore, except for designs made especially for the bronze casting process, all designs should be adapted to allow for the proper casting process. The foundry technicians review the drawings and tub data, together with the patternmaker. During the design adaptation step, the designer s concept and aesthetic priorities are always kept in mind. After all the necessary studies on the design are made, clients are informed of any changes and are asked for confirmation. 2- PATTERN MAKING A pattern is the true shaped model of a casting. The dimensions of the pattern and the final product differ only in necessary allowances to balance shrinkage during the cooling of the tub after casting. The patternmaker starts the process with quality wooden material. The wood must be dry or the shape of the final product can be distorted. These patterns are made manually with attention to detail. The Pattern Making Process Rough Wood Body Pg 1/1
After cutting, shaping and nailing, the surface is ground to obtain a smooth surface finish. If the pattern is not a mono-block (one-piece pattern), each part must be filed to obtain the best match. The Pattern Making Process Assembling the Separate Parts to Check the Matching The wooden body is coated with a special epoxy material. The epoxy fibers are applied manually to the surface. After this application, the surface is ground once more to obtain the best surface quality. The Patterns after Epoxy Coating Next, a special paste is applied to further smooth the surface. The Patterns after Paste Application Pg 2/2
When the pattern is dry, the wooden body is removed leaving the epoxy-based material, which has approximately the same dimensions as the final product. Before the molding process, the final pattern is covered with graphite, to achieve the best removal after sand molding. The Pattern with Graphite covered all over its Surface 3- MOLDING The pattern is used to produce the negative shape of the bathtub in the sand. The pattern is buried into the mold. The sand has special additives (like resin) to hold the shape of the pattern. Smaller sand particle sizes produce higher surface quality. One male and one female mold create the main shape. See photos below. The two molds are fitted together leaving space for the molten metal to form the desired shape. Molding Step Pg 3/3
The Female Mold The Male Mold Molded Bathtub 4- CASTING The bronze is melted in an electric furnace (temperature ranges over 1400ºC). The molds are placed together. The space between the male and female mold halves are filled with molten bronze. Pg 4/4
The Melting Shop Electric Furnaces The cooling and solidification period differs with the shape and geometry of the bathtub. Generally it takes two days for proper full solidification. 5- MOLD CLEARANCE After cooling the surplus sand is removed. The Rough Casting after Mold Clearance Pg 5/5
6- POLISHING The polishing is done manually. Utmost care is taken during this process to achieve the best surface finish. A rough polish is done to view any defects in the cast. Defective tubs are scrapped. Minor bumps or surface blemishes can be buffed out. Fine polishing follows the rough polishing. A special chemical powder is used to achieve the finest surface quality. Rough Polished Bathtubs The casting process is subject to many variables; therefore experience is necessary for a sound casting. The baths are then carefully crated and shipped to customers worldwide. Pg 6/6
Bronze Slipper and Bronze Dual Bath on Plinth Pg 7/7