Patent ID: 7938169

Claim:
A sand core for use in metal casting, comprising: (a) an anti-veining additive composition comprising: (i) from about 20 to about 70% by weight iron(III) oxide; (ii) from about 20 to about 70% by weight iron(II,III) oxide; and (iii) from about 10 to about 60% by weight of a comminuted glass that is substantially free of lithium oxide; (b) an effective amount of polymeric binder; and (c) core sand; wherein said iron(III) oxide and said iron(II,III) oxide are each comprised predominately of particles having a particle size less than about 75 microns and wherein said anti-veining additive composition comprises from about 3% to about 10% by weight based on the weight of sand, said sand core being substantially free of lithium-bearing minerals, and comprising less than 0.001% by weight lithium oxide (Li 2 O).