SAND TESTING

As part of its work in support of the foundry industry, Touchstone acquired an array of sand testing devices including the following:

Sieves for AFS Fineness:

Touchstone has dozens of sieves in-house, ranging in sizes from 325 mesh to 2 mesh. The sieves are placed on a vibratory Riddle and shaken for a prescribed amount of time to allow separation of the various particle sizes.

Compaction , Moisture Content and Crushing Strength:

The compaction, moisture content and crushing strength tests are performed using equipment from the Harry W. Dietert Company. This testing is not typically performed for outside foundries since immediate results are almost always required and the samples are also not "stable." In other words, the mositure content and the mechanical properties change with time.

The equipment exists at Touchstone to support research efforts in sand binders, mold washes and sand reclaimation.

Compaction is a measure of the "moldability" of a sand mixture sample rammed with a standard drop weight. Its bulk volume is measured. The relative decrease in volume is a measure of its compactability.

For moisture content determination the sample is weighed, dried at 110o C and then weighed again. The difference in weight is the moisture content.

Compression or crushing strength is measured using a cylindrical sample and compressing it between platens of a small compression tester.

Permeability:

Permeability is a measure of the ability of a molding sand to allow the flow of gases evolved in a casting. It is determined using a specimen of standard geometry and reported as volume of gas per unit time.

LOI:

Loss On Ignition is performed using a furnace capable of exceeding the casting temperature of the metal in question, (e.g. iron requires a 2600 o F temperature furnace). The Loss on Ignition is the difference in weight before and after ignition in the furnace.