PENGARUH VARIASI CAMPURAN PASIR SILIKA DENGAN WATERGLASS TERHADAP PERMEABILITAS DAN KEKUATAN TEKAN PADA PEMBUATAN INTI (NAKAGO)

The purposes of this study are to determines: (1) the variation effect of silica sand andwaterglass mixture through permeability for manufacturing core (nakago). (2) the variation effect of silica sand and waterglass mixture through compressive strength of the core (nakago) making.(3) the optimal price of the permeability and the compressive strength of the core (nakago) making. This research was conducted at the Polytechnic Metal Testing ManufacturingLaboratory in Ceper using primary materials such as silica sand and waterglass. The research method used in this study is an experimental method. The independent variable in this study wasthe waterglass variations in 5%, 15%, 20%, and 25% level, and the dependent variables are the permeability and compressive strength.Results of this study are: (1) The addition of waterglass at 5% become 15% level is increase, while the 15% become 20% and 20% become 25% are decrease. (2) Increasing in anumber of waterglass level will increase the compressing strength. (3) Waterglass Variation in the level of 5%, 15%, 20%, and 25% obtain a permeability row 90.33, 139.33, 115.30, 91.22, and the compressive strength 11.33, 12, 20, 12.93, 16.50. The smallest permeability of waterglass occurred at 5% ie 90.33 and compressive strength of waterglass occured at 5% ie11.33, while the largest permeability of waterglass occurred at 15% ie 139.33 and compressive strength of waterglass occured at 25% ie 16.33