Standard Test Methods for Fusion Flow of Porcelain Enamel Frits (Flow-Button Methods)

Abstract

These test methods cover evaluation of the relative fusion flow characteristics of samples of a given porcelain enamel by comparison with an established standard for that frit. Two test methods are included, differing only in certain details of the samples and in the apparatus and procedure for preparation of test specimens. Both test methods give equally reproducible results and provide a satisfactory basis for comparison of fusion flow of the sample with that of the established standard. Test Method A employs granular particles of frit to which a bonding agent has been added. Button specimens are formed under high pressure in a hydraulic press. Test Method B employs crushed, sized particles of frit to which a bonding agent has been added. Button specimens are formed in a steel mold by hand. Both Test Methods use a hard steel mortar that is resistant to abrasion by the porcelain enamel frit, a hydraulic press, and a fusion flow rack. The test methods use sieves of different specifications. The steel mold assembly of both test methods consists of a die and plunger, however, Test Method B has an additional back-up disk.