Clay-bonded sand
• Increase bentonite content in the moulding sand
• Use bentonite with a higher specific binding power
• Reduce proportion of fine quartz in moulding sand
• Reduce recirculation of dust; if necessary use bentonites with higher montmorillonite content
• Use coarser moulding sand
• Improve conditioning of bentonite; prolong mixing times; pre-wet used sand
• If practical, reduce amount of new sand to increase the degree of chamottization
• Improve water quality; switch from well water to public supplies; perform partial desalination