Inserts Exothermic and insulating flyweights with high gas permeability.

moldable for producing moldings for the foundry industry, in particular insulating or exothermic feeders and other drinkers and feeding elements for molds, comprising at least bodies mass: - at least 10% by weight of a porous refractory material, It has a continuous open pore structure; - a binder for curing the molding composition; - optionally a refractory filler; - a proportion of a reactive aluminum oxide with a specific surface area of ​​at least 0.5 m 2 / g and an average particle diameter (D50) of 0.5 to 8 microns.