METHODS FOR THE DETERMINATION OF THE FIRING RANGE OF VITREOUS ENAMELS USED IN WET-PROCESS ENAMELING1

Several methods for making firing range studies in case of wet-process enamels are described. The methods used in producing enamel deposits of predetermined weights are given. The use of these methods has shown that enamels used in wet-process enameling of metal vary widely in action under various conditions of heat and a general discussion of the subject is included.     

ACTION OF THE DUST FROM THE BATCH ON THE CHECKER BRICK OF GLASS FURNACE REGENERATORS1

The crusts and glazed slag formations due to the glass batch dust that is carried by the gas current beyond the pots into the regenerators, flues, and burners were examined microscopically by X-ray and chemical analysis. Crystals of nepheline, car- negieite, and mullite are noted. This paper deals with the crusts and glazed surfaces in the regenerating chambers of two different pot furnaces.     

PRODUCTION OF A SALT GLAZE BY THE APPLICATION OF A SLIP TO THE WARE1

Glazed surfaces can be produced on the face of ware mode from practically any clay or shale having maturing temperature of cone 1 or more by coating the face of the ware with a slip containing sodium chloride. Various concentrations of salt in the slip have been used. Lower concentrations do not produce glazes but develop interesting surface and color effects. Metallic oxides may be used to produce variation in color of the glaze. This method shows promise as a means of securing salt glazes in kilns which have heretofore been considered impractical for salt-glazing purposes, although it has been developed only in the lahoratory stage at the present time. Sodium carbonate has also been used successfully.     

SOME SIMULATIVE SERVICE TESTS FOR GLAZED BUILDING MATERIALS1

Several methods of freezing and thawing tests have been compared with each other and with the standard autoclave test with regard to type and rate of failure. Data indicate that the autoclave test alone is not sufficient to predict behavior of glazed ware in service, especially in the more severe climates. Glazes follow very definite laws as to rate of failure under conditions of freezing and thawing. Curves have been developed which indicate the nature of these laws very clearly. Considerable data have also been obtained on the effect of freezing on the porosity of brick and on the nature of failure of glazes.     

THE PHYSICAL PROPERTIES OF THE FINENESS FRACTIONS OF SLAKED SEMIFLINT CLAY1

A select sample of Missouri semiflint clay was slaked to its natural size of grain and screened into the following sizes: on 20, 20 to 40, 40 to 60, 60 to 100, and through 100-mesh. The 100-mesh fraction is a very dense firing clay, giving a high dry and fired modulus of rupture, and would be effective as a “dope” for a weak clay. The properties of the intermediate finenesses are substantially an average of the properties of all the finenesses. Points of inferiority in the coarse fractions are supplemented by points of superiority in the fine fractions, and vice versa. All fractions are therefore desirable, and further, there are indications that no substantial improvement could be made by screening out any one of the fractions.     

THE RELATION OF METAL CLEANING TO PERFECT ENAMELING1

The importance of the cleaning phase of the enameling process as related to production of uniformly good work is not always appreciated. Many troubles encountered commonly in porcelain enameling plants can be traced to the pickling department turning out unclean work. In order to control the cleaning properly there are a number of points which should he considered, such as type of lubricant used, production schedule, evidence of water hardness, and selection of proper type of cleaner. A method has been suggested which applies to the water-break test for determining the exhaustion point of the cleaning tank. Rinsing, packing or racking, and electrolytic cleaning are also of importance and merit consideration.     

The margarine industry of Europe

Recent mergers, acquisitions by the European margarine trust, and intensive merchandising campaigns throughout Europe to increase the popularity of margarine and expand the consumer markets for the product, have accentuated interest in this industry abroad. This article, therefore, as it embraces all of the leading margarine producing countries of Europe, is offered to fill a want and supply a service of information of particular interest to manufacturers of margarine and producers of other fats for food purposes in the United States. Published by permission of the Bureau.