Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Page 35 of 707

Table I. Commonly Used Buff Fabrics Warp Filler (Lengthwise) 60 80 86 86 86 (Crosswise) 60 80 80 80 80 Cloth Weight (Linear yd/lb of 40-in.-wide material) 3.15 3.15 2.50 (soft) 2.50 (firm) 2.50 (yellow treated at mill) ed, fabrics are designated by thread count (e.g., 60/60, 80/80, 86/80). These des- ignations refer to the threads per inch in the warp and fill, respectively. Fabric weights typically run from 2.5 to 3.5 yd/lb. (Table I). OTHER BUFF MATERIALS Flannels Domet flannel (with nap on both sides) and Canton flannel (nap on one side and twill on the other side) in various weights are used where other fabrics fail to pro- duce a high enough luster. Coloring of jewelry products is a typical application for such buff materials. Sisal Sisal is a natural hemp fiber used for fast-cut buffing of steel and stainless steel. It is a coarse fiber twisted into strand groups and frequently woven into a fabric. It has a much lower thread count than cotton muslin, sometimes five by seven per inch, and offers the advantages of greater surface defect removal. Combination sisal/cloth buffs are effective designs (Fig. 1). The sisal plies frequently are cloth covered to omit the tendency of the sisal to cut the cotton threads of adjacent cloth plies. Alternating cloth and sisal improves compound retention, reduces unravelling, and moderates cut. Kraft paper alternated with sisal also has appli- cations. Other Natural Materials Occasionally, other materials are used to form buffs. For example, woven wool buffs are used on plastics, soft metals, and sterling silver. Sheepskin buffs are used to avoid surface drag or smear when buffing metals that contain lead. Russet (bark-tanned) sheepskin is used for cut. White alum (alum-tanned) sheepskin is used for color buffing. Pieced Buffs Pieced buffs are less expensive because they are made of lower-cost materials. The buffs are made of colored segments, unbleached segments and occasionally bleached material. Combination Buffs Often different materials are combined, especially sisal with cloth, and occasionally paper as well as cloths of different specifications. Synthetic Fibers Unwoven nylon and other synthetics fibers, because of their water resistance, may be used wet or dry or with wax or grease lubricants. Buffs made of synthetics are usually operated at slow speeds, typically 2,500 sfpm, to prevent melting and streaking surfaces. 34

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