Abrasion tester 820

The Falling Sand Abrasion Tester - Model 820 is a popular apparatus used to measure the resistance to abrasion of paint, lacquers and other organic coatings. Abrasion results from abrasive particles falling through a guide tube and impinging the test specimen, until the substrate becomes visible. Description Based on a design described in ASTM D 968 and other internationally recognized test standards, the Falling Sand Abrasion Tester consists of an 8" diameter sand reservoir which includes a 60° taper funnel. Standardized abrasive particles placed in the reservoir are released to a guide tube by an abrasive flow gate key. The guide is a 36" straight, smooth-bore tube which contains the abrasive particles as they fall. Specimens are fixed under the guide tube at a 45° angle in a receptacle that includes an opening at the bottom allowing the abrasive particles to be collected in a container. A sturdy base and support system hold the apparatus in a vertical position. Abradants Although a variety of abrasive particles have been used, silica sand and various grades of silicon carbide continue to be most popular. To ensure reproducible results, the abrasives must be graded to a particular sieve size. Note: Silica sand is typically characterized by its roundness of grains and produces a slower rate of abrasion on organic coatings. It has been noted that for 3 mil dry film thickness, many of the older coatings would require 20 to 200 liters of silica sand to achieve a failure. Today's more durable coatings may require up to 600+ liters of sand to wear-through.