Metal Finishing Guide Book


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rials as fatty acids, tallows, and glycerides. Waxes can be from vegetable, insect, or petroleum-based products. Petroleum-based or vegetable-based oils also may be used. The animal and vegetable materials are more saponifiable and will produce a water-soluble soap when combined with alkali. Petroleum, mineral oils and waxes are unsaponifiable and, therefore, might create subsequent cleaning problems. Each ingredient is added to the binder to transmit a specific effect to the bar compound such as lubricity, degree of hardness, or improved adherence to a buffing wheel. A binder also controls the amount of frictional heat that can be developed on a surface. This is called slip. There is a wide range of abrasives used in buffing compounds, a few of which will be described. BUFFING ABRASIVES Aluminum Oxide and Other Powders Aluminum oxide powders, fused and unfused, are the abrasives most commonly used in the buffing of hard metals. Chromium oxide is used to achieve the highest reflectivity (color) on stainless steel, chromium, and nickel plate. To achieve a high reflectivity (color) on brass, gold, copper, and silver, iron oxide is generally used. Aluminum oxide is chemically represented as Al2O3. The unfused aluminum oxide is white in color. This is manufactured from bauxite or hydrated aluminum oxide by heating it at elevated temperatures. This heating process, called calcination, gives the abrasive the common name calcinated alumina. The higher the calcination temperature, the more water of hydration is driven off and the harder the crystalline material becomes. When the calcinated temperature is about 950oC, the product produced is a soft alumina having a porous structure. This type of abrasive is used for luster or color buffing. When the calISO 9001: 200 Certified cined temperature is about 1,250oC, a harder alumina is produced. This type Manufacturers of fine polishing of abrasive is used for cutting. Soft compounds for over 8 years. aluminas are used to produce luster or a higher reflectivity on all metals, ��� BARS ��� LIQUID ��� PASTE both ferrous and nonferrous. The ��� BUFFS ��� BELTS harder aluminas will cut and remove more metal from the surface of castFor Metal, Fiberglass, ings or extrusions of aluminum, brass, Marble and Paint and other metals. All compounds are crystalline When alumina is heated to silica free. 1,850oC, fused aluminum oxide Private labeling available. (Al2O3) is produced. This material is made in an electric furnace at approxCUSTOM KITS LUBRICANTS imately 2,000oC. Bauxite, when mixed SPECIALTY DEGREASERS with alumina and other oxide materials, produces a specific crystalline 4800 South St. Louis Avenue structure whose hardness can be varChicago, Illinois 60632, U.S.A. ied to meet specified physical propPhone: 773-847-1111 erties. This fused mass is then cooled Fax: 773-847-3399 and crushed. In the crushing process, email: the material is ground, screened to the appropriate size, treated ically, and acid washed. It is then ��� ��� ��� 21

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