MATERIALS AND HOW TO TEST THEM
Likewise the best grades of cotton yarns are the well twisted plied yarns, made of long-stapled combed fibers.
Pull out single warp and filling yarns from your sample of cloth and examine carefully the evenness, twist, ply, elasticity, and strength. Untwist a yarn and examine the arrangement of the fibers. Then gently pull the fibers apart, being careful not to tear them, and observe their length.
Finish and Weighting: A material is often weighted and finished with foreign substances to give it more body and the appearance of a very good grade of goods when in reality it is very poor.
A woolen fabric is sometimes weighted and finished with a mass of very short wool fibers from clippings called flocks. These are sprinkled thickly over the surface and pressed well into the cloth. Then the cloth is filled and finished. This makes it thicker and heavier but the little fibers soon rub and brush off with wear and leave a threadbare, miserable looking fabric. If a sample of cloth is rubbed and brushed thoroughly any surface finish of this kind is quickly revealed.
Most silk materials are weighted more or less with tin salts or other metallic salts.
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