Making Of Brass Frame For making brass frame, old brass utensils and other brass materials brought from Mannar local market is used. A ‘kovva’ or crucible made of wrought Iron is cleaned. These brass pieces are added in proportion into the crucible. The kovva is then placed in an open pit furnace charged with burning charcoal.It is then surrounded with pieces of ‘thoundu’ or coconut husk, as ‘thond’ retains the heat. It is heated to about 4000C (approximate melting point of brass). The molten metal is poured onto flat surface usually the ground itself or a metal box filled with soil. The flat surface will be having impression of the mirror frame design which is finised with clay. The molten metal is then poured into the moulds. It is then left for cooling. Once cooled, the clay mould is broken and the casting is removed. The casting is checked for any deformalities. The frame in its crude state is filed and a brass sheet is cut and soldered on to the back side of the frame. Normally mirror frames are flat in shape. Now a days customized designs are also made, incluing 3d frames. And the design is first made by using mseal. Designs are punched on the frame. It is then buffed to give a final polish. The mirror is stuck to the frame with gluing wax. A brass ring is used to secure the mirror to the frame.
Making Of Mould For Brass Frame Traditionally the mould for the master model for the brass frame was casted using the lost wax process. The wax used was composed of chanchaliyam, ordinary wax and edible oil. The wax is heated and is then rolled to uniform thickness using a roller. The required pattern of the frame is first drawn on a piece of paper and is then cut. This paper is
then placed on the rolled wax. The wax is cut along the contour of the pattern. Now they use cardboard instead of wax. To get different contours on the surface of the mirror that many layers of wax is placed or spread on the base layer. A plug made of wax is vertically placed on top of wax pattern. Once this is done, finely ground soft clay is prepared by grinding it on ‘ ara kallu’. This soft clay is first applied on the wax pattern and is compacted to get the exact contour of the pattern. It is left to dry. Then coaser clay is applied on the surface of this clay. A ‘thaalu’ (or pouring hole) is made on the mould just above the wax plug. It is again letf to dry for a day. The mould is then placed inclined near a pit, with the plug facing downwards. Pieces of ‘thondu’ are placed on top of the mould and are then set to fire. Once heated to the suitable temperature, the wax pattern along with the plug melts and flows down into the pit. The hollow cavity formed inside is the exact replica of the pattern. The mould is now ready for casting. After the master mould has been made and it is used to cast more frames using the sand casting process as it is much easier and the chances of the design to retain its form is more in this process. Unlike the lost wax process where the wax has to be remoulded here the master model can be used many times to make the patterns of the frame. In the sand casting process the master metal model which has been cast is used to make the pattern in two aluminium boxes. The lower box is filled with the sand (mixed with clay which acts as the binder) and compacted by ramming manually. The master metal pattern is centrally placed inside the lower box and compacted the extra sand is removed. The path for the metal to flow is made. Parting material which is tile powder is spread over the drag using kizi, two plugs are placed so as the guide the molten metal in the core.The upper box is placed over the lower box and again sand mixed with clay is compacted manually. The two plugs which are
Aranmula Kanndi 49