metal or alkaline earth aluminates colloidal oxide hydrosols and clays a preferred class of coating materials are those having a composition in the following ranges by weight silica flour 30 80 sand 18 50 sodium aluminate orsodium silicate orsodium metaphosphate 0 5 5 ball clay 0 5 5 the thickness of the second coating may be for example 5 25 mm the second coating may be applied by any convenient means for example by trowelling coke dust 22 mesh bss 99 75 by weightsodium carboxymethyl cellulose 0 25 by weight this was mixed with water to form a paste which was applied at a thickness of 2 5 mm silica flour 49 5 by weightsand 46 5 34 sodium metaphosphate 2 0 34 ball clay 2 0 34 this coating was trowelled on to a thickness of 12 mm these two layers were applied to the refractory brick lining of a 50 tonne capacity steel casting ladle for use in continuous casting and were reapplied after each casting cycle the ladle did not have to be taken out of service for replacement of the brick lining until more than 20 casting cycles had been carried out normally using conventional refractory dressings replacement of the brick lining was necessary every four or five casting cycles equally good results were obtained using the same.