Page 83 - Superior Abrasives sold by All Industrial Tool Supply

Coated Abrasives 81

Backing Materials
Various backings help determine material strength, durability and flexibility – All
critical factors when considering particular applications . Cloth backings consist
of either cotton, which is most popular, or a more performance-oriented poly-
ester, which provides better grain retention . Cotton backings are classified by
flexibility, versus the weight of paper backings .

Backing Types
Paper Cloth
Weight
A B C D E F E F J T X Y Z

Durability

Thickness

Flexibility

Base & Size Coat

The manner in which abrasive grains are adhered to the backing is done with
a base coat . Grains are set in a resin or glue that secures grains upright and
in place . On top of the grains and base coat, another layer of resin is applied,
creating the size coat . Various alterations to resin compounds allow more or
less flexibility of the abrasive grains, sometimes creating a stiffer, more durable
product .

Top Size Coat
To counteract friction, excessive heat or loading, an additional layer may be
added to coated abrasives . Top size coats can be utilized as a grinding aid or a
stearate, which is commonly seen on products with paper backings .

Top size grinding aids react to high heat caused by friction from harder metals
and alloys . Necessary pressure can be applied, but heat is not generated as
quickly, reducing the stress and premature wear of the abrasive grains .

In lower temperature operations, a top size stearate may be preferred . Calcium
stearate acts as a lubricant that reduces loading and clogging of softer metals
with a lower melting point .

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