ASTM C1276-94(2005)

The viscosity of a molten mold flux is a very important property for the correct functioning of a mold powder. This procedure is designed for producers and users of mold powders to develop the viscosity-temperature relationships of the molten mold flux for quality control or specification purposes, or both. Practice C 965 was developed for glasses that are significantly higher in viscosity than mold powders. Also, sample preparation is very different for the glass products covered.

Note 1—Warning: Use caution when discharging molten sample into water since this can cause an explosion.

1.1 This test method covers measurement of the viscosity of mold powders above their melting point through the use of a platinum spindle immersed in a platinum crucible containing the molten mold flux. Developed by differential angular velocity between the crucible and spindle, spindle torque is measured and used to calculate the viscosity. Data are generally taken as a function of temperature to describe the viscosity-temperature relationship for the molten mold flux.

1.2 This test method uses a high-temperature furnace and measurements on molten material. Personal protection equipment to wear include high-temperature resistant insulating gloves, coveralls, and a full-face shield.

1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A specific warning statement is given in Note 1.