The filter pressed body cake is mixed with required quantity of water approximately 35%. Small addition of deflocculants like sodium silicate and sodium carbonate is added to from a fluid slip which can be easily poured into the moulds. The casting process involving removal of the slip should be maintained very high without compromising on flow behavior. The casting rate and the properties of slip and hence we need to check the flow behavior of the slip regularly to maintain consistency in the slip.
Inconsistency in the slip can lead to such troubles as flabby casts which cannot be finished satisfactorily or castings may collapse while removing from the mould or develop cracks etc. During casting the slip must not be exposed unduly to air since a reaction of the alkali with carbon dioxide leads to the formation of compounds like bicarbonate of soda which causes the slip to thicken causing a defect called levering.
To be continued……..
