I arranged with Sukanta Banik to re-visit Dhamrai Metal Casting, to see in more detail the way in which they make the wax models for casting and to learn more about how they work.I travelled with Shawon on the bus, back past the brick fields to Dhamrai, 39km north-west out from Dhaka. See part of the journey here: Journey out of Dhaka.
We stopped on the main road which passed by the small town, then took a cycle rickshaw to Banik House in Dhamrai Bazar.The metalworking industry has existed across the whole of the area now known as Bangladesh. Dhamrai has always been a major centre for this craft. Whilst the area still has lots of workshops, the traditions and skills are slowly disappearing, mass production, plastics, cheap ceramic-ware and shifting economics mean that few families continue to work metal and make in the traditional way.
Dhamrai Metal Casting produces designs cast in bronze, brass and bell metal, using lost wax techniques that are hundreds of years old. Designs are based upon historical artefacts, some dating back to the 11th century (mostly statues of gods, godesses, animals and birds).
A large sheet of wax rolled out using a rolling pin then cut to shape. This will form the back-drop for a piece.
Small 'sprig' moulds, made from clay, are used when consistent details are needed.
A small kerosene lamp is used to give intense localised heat to tools and wax objects. Bowls of water are used to cool the wax once it is formed. 
The wax is made from parafin and beeswax. The correct combination is needed to ensure the wax is hard enough to hold its shape but soft enough to be modelled. Sheets are cast by pouring the wax into bowls of water.
The sheets are softened under the lamps and then cut, molded or rolled into the required shapes.
I liked the detail of the hair
I took a walk around Dhamrai by myself and stopped to watch the local jewellers working in their workshops.
When soldering they use a oil burner and blow down a small tube to increase the heat and direction of the flame.
Dhamrai Metal Casting produces designs cast in bronze, brass and bell metal, using lost wax techniques that are hundreds of years old. Designs are based upon historical artefacts, some dating back to the 11th century (mostly statues of gods, godesses, animals and birds). The lost wax process involves constructing a model from wax then creating a refractory shell around it. The wax is burnt out of the mold and the resulting void is then filled with molten metal. When the metal has cooled the shell is removed/destroyed exposing the metal casting in the same design as the wax model. This is then cleaned and finished.
Modern production processes use moulds to reproduce the wax models, at Dhamrai pieces are singular and unique, each of the wax models are made and modelled by hand, ensuring the fine detail of the designs and at the same time preserving a craft tradition. Sukanta Banik is the 5th generation of metalwork traders in his family. The casting centre runs training sessions for students, an apprenticeship scheme and runs a skill exchange programme. They are also documenting the different metalworking techniques of the region.
The wax models are made in sections or components which are gradually added to each other to make the final design. Some pieces can take up to six months to make and, with no moulds, if the casting fails, all work may be lost.
Seat modelled from wax.
Arms and head of Ganesh waiting to be added to the main model.
Small 'sprig' moulds, made from clay, are used when consistent details are needed.
Skilled hand work produces the other details on the figures and their supports /surroundings.
Improvised tools are made from shaped bamboo, old sawblades and a craft knife blade to cut and model the wax.
Arm ready to be attached.
Hot blades are used to soften and then attach the elements together.
A bamboo stick is one of the tools used to blend and smooth the wax components.
Banik House is built around a courtyard, rooms leading off the central space and the verandas form the spaces where men work on the different stages of the casting process.
The wax modellers work in a room around a small table with a hood fitted.
The hood is made from timber and sack cloth. It contains 4 x 200 watt electrical bulbs. They create an warm environment which softens the wax and allows it to be maintained at a workable temperature.
A small kerosene lamp is used to give intense localised heat to tools and wax objects. Bowls of water are used to cool the wax once it is formed. The wax is made from parafin and beeswax. The correct combination is needed to ensure the wax is hard enough to hold its shape but soft enough to be modelled. Sheets are cast by pouring the wax into bowls of water. The sheets are softened under the lamps and then cut, molded or rolled into the required shapes. Sheets and components need to be of a thickness that will leave a void in the shell large enough to allow the molten metal to run freely.
Click here to see: Dhamrai Metalworking Waxworking 01
Click here to see: Dhamrai Metalworking Waxworking 02
Click here to see: Dhamrai Metalworking Finishing
The models are cleaned and polished at regular intervals to remove fingerprints, loose scraps and marks. Emery paper, a cotton cloth and a tooth brush are used for this.
When the wax model is complete and finished, the process of making the refractory mould or 'shell' begins. Local clay is made into a solution and layers are painted onto the wax model.
Initially a very fine layer of clay is used to cover the wax, this is allowed to dry over 1 - 3 days, then a further layer is added. The fine clay is added carefully in order to ensure that the detail of the wax work is captured.
Subsequent layers use the same clay mixed with (1) jute fibre and sand (2) Clay mixed with rice husk and sand. Steel wire is embedded between the later layers to strengthen and support the mould reducing the risk of cracking when it is baked in the furnace (1000 degrees) and when the molten metal is poured in.
Jute fibres
On large moulds, to reduce the weight of the object and use less wax and metal, cores are made to create hollow objects. The core for the object is made from straw or jute, which is then covered and modeled with clay.
Sheets of wax are applied to the core and then modeled, detailed and finished in the same way that a solid wax model would be.
Moulds ready for casting, including the pouring spouts or 'sprues'
The mould and the crucibles ( filled with the metal) will all be place in the furnace at the same time. The wax is burnt out of the mould ( hence lost wax) and the mould is brought up to a temperature, that reduces the risk of thermal shock damage when the molten metal is poured.
Working the wax: Heating a metal bar used to smooth sheets of wax together.
Using a bamboo tool to create the effect of pleats in fabric.
The finished wax article ready for being covered with clay.
Due to the skill of the wax workers and mold makers there is relatively little finishing required once the mould is cast. The workmen use files and abrasive papers to remove small lumps and defects from the surface. If the metal has not run fully through the mould during casting any small holes or faults can be welded.
The men work in the shade of the veranda around the courtyard.
I liked the detail of the hairThe pieces are 'antiqued' using acids, oils and chemicals to colour and 'age' the pieces.
The range of pieces cast includes decorative and functional items on a range of scales.
I thought the Alpana painted on the veranda very beautiful.
I thanked Sukanta and his family for their time and left to catch up with Shawon, who was filming at a local school.
I thanked Sukanta and his family for their time and left to catch up with Shawon, who was filming at a local school.
I took a walk around Dhamrai by myself and stopped to watch the local jewellers working in their workshops.
When soldering they use a oil burner and blow down a small tube to increase the heat and direction of the flame.
