Grinding and Polishing - Choosing The Right Compound

Introduction

Polishing compounds are abrasive or burnishing compounds composed of polishing powder mixed with a binder of fats and waxes to form wax-like bars or cakes. Polishing compounds fall into three major categories: tripolis (cutting compounds), intermediates (combination compounds that cut and also impart some luster) and finishing rouges (burnishing compounds).

The term "cut", used when describing a polishing compound, refers to how fast the compound removes metal (cuts) to produce a smooth surface. A "high" cut removes much metal. A "low" cut removes very little metal. A cutting compound is a fast-cutting abrasive used to remove emery marks and fine dull scratches. It leaves metal surfaces very smooth, although dull in appearance. It is used with felt ring buffs, felt wheels, polishing brushes and yellow treated buffs.

The term color refers to the luster or shine jewelry has after polishing. A polishing compound with a low color, such as some intermediate compounds, will cut more than it polishes. A medium color, characteristic of most intermediate compounds, indicates the compound will yield a fair amount of shine, but not a final finish. Polishing compounds with high color, imparted by Shor's finest rouges, give jewelry the highest shine.

The usual method of polishing occurs in two steps: cutting with bobbing tripoli and shining with a rouge. Polishing in three steps by using an intermediate compound between the tripoli and rouge, will produce a shine superior to that produced by the two step process.

• Tripoli: Shor Bobbing Tripoli compound is the recommended tripoli for the best fast cutting.
• Intermediates: Shor Greystar is the best lapping compound used mostly on felt wheels to produce smooth lapped surfaces without lines on the metal. "J" Yellow and "M" Blue are intermediates compounds that will color more than cut. White Diamond compounds are dry and have little cutting action.
• Finishing Rouges: These fine compounds produce the final luster. Finishing rouges are usually used with standard buffs, but may also be used with brushes, felt ring buffs and felt cones. Shor Zam Rouge and Shor Fabuluster are very versatile rouges that can be used on all metals with excellent results. Fabuluster impart an especially high luster, a higher luster than any other compound. Shor Red Rouge is an excellent finishing compound suited to virtually all gold and silver jewelry. Shor White Rouge is popular for platinum and silver but Shor Green Rouge will impart a higher luster to platinum, silver and gold.

Grinding with Shor MX Wheels

Shor MX Wheels remain the best way to remove sprues, parting lines and other grinding work. They give a better quality result as well as being faster. MX Wheels will not clog or load as ordinary grinding wheels do. In addition, gold recovery is much more efficient when using a polishing or grind hood (call Shor to ask for gold recovery and /or refining brochures for information on gold recovery and refining).

1. To use the MX wheels, put them on the arbor if they have a 1/2" center hole or put them on the tapered spindles if they have a smaller hole. Put them in so that the printed information which is on the wheel will face the motor. In this way, the information will always be on the wheel so that you can know how to reorder additional wheels. When the motor is running and the wheel is turning, press the diamond point of the diamond dresser against the side of the wheel to remove the surface skin. Then press the flat of the rough carborundum stone against the side of the wheel for about 20 seconds. The wheel is now ready to use for grinding flat surfaces.
2. To use the edge of the wheel for rounding the shanks of the rings cut a groove (with the diamond dresser) into the edge of the wheel. Shape the groove to correspond with the outside contour of the shank of the ring.
3. No compounds are needed. You are now ready to work.
4. The drum sander, (with metalite cloth on its face) is used for the same purposes as the MX wheels. It is used when you feel that the cushioned surface (because of the rubber under the metalite) may be better for a particular type of work.

Grinding with the Shor Drum Sander

When using the Whirlwind Flanged arbor with a drum sander, the flanges should not be used. The removal of the flanges will allow the tightening nut of the arbor to have sufficient grip to hold the sander tightly closed.