BUFFING

Figure 14-2.—Buffing wheels. Nos. 400A, 500A, and 600A. Wash the plastic after each operation. During each step, the deeper scratches left by the preceding grade of abrasive should be removed. BUFFING.—To remove the fine, hairline scratches caused by sanding, transparent plastic may be buffed. It is often possible to remove scratches by buffing alone, provided the scratches are not too deep. There are a number of standard commercial buffing compounds satisfactory for use on transparent plastic enclosures. They are usually composed very fine alumina or similar abrasive in combination with wax, tallow, or grease binders. They are available in the form of bars or tubes for convenience in applying to the buffing wheel. Plain tallow is often applied to the buffing wheel. It may be used in addition to buffing compound, or it may be used alone. In the latter case, tallow functions similar to wax as it fills in hairline scratches and gives a high gloss to the surface. Buffing wheels are made of cotton cloth or felt. For removing scratches caused by sanding, an of “abrasive” wheel and a “finish” wheel are needed (fig. 14-2). The abrasive wheel, which is relatively 217.162 Figure 14-3.—Buffing wheel mounted in portable drill. 14-4