Abstract: A cold-setting moulding mixture, comprising a resin binder capable of setting at room temperature in the presence of an acid catalyst. The composition of the cold-setting mixture incorporates also phenoxyalkylalkoxysilane introduced as an additive add having the formula ##STR1## where "X" is selected from a hydrogen, alkyl-, alkoxy-group and the --O(CH.sub.2).sub.n --Si(OR).sub.3 group, "n" = 2-3 and R is a C.sub.1 -C.sub.4 alkyl radical. The additive is introduced in an amount of from 0.1 to 1.0% by weight of resin.

Abstract: A self-hardening moulding mixture for making foundry moulds or cores, comprising moulding sand, orthophosphoric acid, a ferrous oxide-containing material, a water-soluble salt of an alkali metal or ammonium, and a carboxylic acid having one dissociation constant not exceeding 10.sup.-4 or a water-soluble salt of an alkali metal or ammonium, and an isopolyacid formed by a chromium subgroup metal, manganese oxide or urea.The self-hardening moulding mixture can also comprise a surface-active substance acting as a foaming agent in order to render the mixture to a fluid state and to avoid compacting when producing moulds and cores therefrom.The moulding mixture features an enhanced bench life (10-15 min) and ensures a sufficiently high hardening and strength rates (compression strength is equal to 10-25 kg/cm.sup.2) for the foundry moulds and cores produced therefrom.

Abstract: A method for making foundry moulds and cores, according to which a self-hardening in the air plastic or liquid mixture is employed. Most advantageously the present invention may be used in making large-size foundry moulds and cores. The proposed method tends to increase substantially the thermal stability of both the moulds and cores due to the effect which the properties of the materials, utilized as a binder, exert on the sand. In addition, the hardening rate of the mixture is increased which is coupled with the simplified knocking-out of the sand from castings.