Fabrication of mambong pottery by using slip casting method

In Malaysia, there are several types of potteries known which are Sayong pottery in Kuala Kangsar, Perak, Terenang pottery in Tembeling, Pahang, Sarawak pottery and Mambong pottery in Kuala Krai, Kelantan. Mambong pottery was being made by traditional technique. In this research, slip casting method was introduced and used in producing pottery. This method used porous mold which able to absorb water content from the clay slip. The objective of this research was to fabricate the Mambong clay sample by using slip casting method with different composition of water and study its effect and properties. Then, the samples were characterized by its specific gravity (S.G.) of clay slip, casting process, drying and firing linear shrinkage, density and porosity and strength of the clay samples.
In this research, Mambong clay was taken from the Mambong Village and the particle size was controlled to below 425μm. The clay slip was mixed with water at different composition which labelled as 50C50W, 60C40W, 70C30W and 80C20W samples with addition of 0.7% of sodium silicate, Na2SiO3 as deflocculant. The clay slip was left for one day for aging process. Then, the clay slip was poured into the mold and as the clay slip solidified as green body (clay sample), it was ready to be removed from the mold and left for drying. The samples were sintered at 900°C with heating rate at 4°C per minute in the furnace.
The samples were characterized by its raw material and fired sample. From this research, 70C30W was the optimum composition to be used in fabricating pottery by slip casting method. 70C30W have the higher S.G. of clay slip at 1.78 which within the range of the best S.G. of clay slip compared to 50C50W and 60C40W. The time taken for sample removal for 70C30W was the shortest. 70C30W also have the lowest for its drying and firing linear shrinkage at 5.81% and 0.77% respectively which also lower than Sayong clay drying and firing shrinkage that have 6% and 10% respectively. The modulus of rupture (MOR) of 70C30W showed the highest value at 36.91 N/mm2 compared to 60C40W that have 22.96 N/mm2.
However, the density and percentage of porosity test showed that 70C30W have low density and low percentage of porosity while 60C40W have high density and high percentage of porosity where the value of density should be vice versa. This was due to errors that had occurred during the test was conducted like calibration error. More research and study about Mambong pottery should be done to obtain optimum parameters in fabricating high quality of pottery.