Faceters Guild Workshop

A discussion of polishing laps

by Nancy L. Attaway

The New Mexico Faceters Guild held a workshop at the home of Steve and Nancy Attaway on July 13 that lasted until 5:00pm. Ernie Hawes organized the workshop and served as its moderator. He was assisted by Scott Wilson, Steve Attaway, and Nancy Attaway.

Ernie Hawes began the morning session with a classroom discussion regarding polishing laps. A handout sheet listed his suggested polishing laps and polishing compounds, and he discussed each one on the list. Nancy Attaway provided comments and information.

The list began with the Lucite Lap and cerium oxide polishing compound. Lucite laps are used for polishing gem materials with a low to medium hardness. The laps, however, will round the facet edges. Cerium oxide polishes any silica-based gem material, which encompasses a variety of gems. These include opal, quartz, beryl, tourmaline, benitoite, tanzanite, peridot, and labradorite. The Dyna disc polishing lap charged with cerium oxide also works very well and can be re-charged. These eventually need replacement.

The Dyna System of laps and discs provide a variety of grinding laps or discs in many grit sizes. The cutting laps are resin-bonded diamond on thin copper discs. These seem to generate less of a damage layer than the steel laps embedded with diamond, especially the steel laps in coarse grain. They also have available several types of polishing discs (cerium oxide, aluminum oxide, and tin/lead) that are already charged with polishing compounds. The Dyna System of laps and discs requires a master lap to place the disc upon and an adaptor for the spindle on the faceting machine.

Ernie Hawes and Nancy Attaway recommended using the Dyna System of discs and laps for grinding and polishing. Nancy Attaway also recommended using the 1200-grit grinding discs from Hi-Tech Diamond Products as a good pre-polish lap. These discs also require a master lap but not an adaptor.

Phenolic Laps charged with diamond are used to polish gems. These laps were used years ago before the newer polishing laps became available. Tin laps, tin/lead, and tin/type-metal laps charged with diamond or aluminum oxide are used to polish gems, like topaz, chrysoberyl, garnet, peridot, tourmaline, and beryl.

The Last Lap and the Fast Lap polish a variety of gem materials, but they tend to round the facet edges. Both laps are a resin-bonded zinc. A Last Lap or a Fast Lap charged with diamond polishes garnet, peridot, beryl, tourmaline, quartz, labradorite, and chrome diopside and can polish harder gems, like cubic zirconia.

The Corian Lap charged with diamond polishes a variety of gems that include topaz, liddicoatite, beryl, tourmaline, tanzanite, benitoite, peridot, garnet, and chrome diopside. Nancy Attaway originally purchased a Corian lap just to polish topaz, but she soon realized how well it polished many other gem materials.

The Ceramic Lap is the lap most used by competition faceters because of its attributes. The ceramic lap charged with diamond gives a high polish, makes flat facets, and allows crisp meetpoints. It is usually used to polish harder gem materials, like corundum, but it can polish cubic zirconia, beryl, and liddicoatite, if the facetor is careful. Nancy Attaway also uses a ceramic lap to polish in the small sliver facets in a pavilion and the small star facets on a crown in garnet and peridot. She remarked that certain placements on a ceramic lap of long and slender facets to be polished is important, as the ceramic lap will spread a facet one way and elongate a facet another way. Nancy also said that there are times to use firm pressure and certain situations to use a light touch when polishing with a ceramic lap. Small facets polished on the ceramic lap will come in fast and can spread too far with too much pressure.

The Wax Laps come in red, blue, and green colors that designate three different hardnesses. Wax laps charged with either diamond or aluminum oxide polish very soft gem materials, like apatite, calcite, kyanite, barite, fluorite, gypsum, and even kunzite.

The Batt Lap is a new type of polishing lap composed of tin and antimony. It was invented by Jonathan Rolf. A Batt lap charged with either diamond or aluminum oxide polishes a variety of gem materials, including quartz, beryl, tourmaline, topaz, cubic zirconia, and corundum. The Batt lap requires some preparation in embedding the diamond compound into it before it can be used. Ernie Hawes is very happy with his Batt lap.

The Pol-a-gem Lap, invented by Glenn Vargas, is a lap with a thick coating of cerium oxide and used to polish quartz. Neither Ernie or Nancy can get their Pol-a-gem lap to work for them. However, Nancy has just gotten the lap to work on a few facets on a quartz.

The Copper Lap charged with diamond polishes harder gem materials and gives flat facets. Nancy mentioned the Meehanite Iron Lap (iron with graphite particles) that is used by the diamond cutting industry. She has one of these laps. She used it once for polishing a large synthetic corundum alexandrite, where the ceramic lap with diamond would not yield a polish.
Ernie mentioned the Spectra laps, thin films placed on a master lap used for polishing. These are available in coatings of cerium oxide, aluminum oxide, tin oxide, and zinc oxide. Spectra laps come in packs.
Ernie also mentioned a special chrome oxide lap that he purchased years ago that was to be specifically used for polishing emerald. Nancy has the chrome oxide lap that Louie Natonek had purchased at that same time. Charged with diamond, the chrome oxide lap polishes beryl and tourmaline.

Ernie concluded the discussion on polishing laps and polishing compounds with brief remarks about colloidal silica. Colloidal silica, found in certain orange juices for particle suspension, is a polishing compound. It was popular in the late 1980’s but fell out of favor due to health fears. When dry, it causes silicosis

Nancy ordered pizza for lunch and served Kona coffee, brewed iced tea, and baked a pineapple upsidedown cake. Becky Hawes baked an apple cake. Margaret Magail Medina made tortilla roll-ups with Philadelphia cream cheese, green chili, and green olives and baked lemon cookies with pecans. Thank you all very much. We eat well at workshops.

Carsten Brandt worked with his RayTech Shaw on a triangular “Apollo” cut orange Mexican opal. Doug Stone worked with his Ultra Tec machine on cutting a heart shaped pink cubic zirconia. His daughter, Aurelia, worked on one of Ernie’s Facetron machines and completed cutting a square almandine garnet.

Phil Callow finished the pavilion of a cut corner square of an oro verde (green gold) citrine with his Facetron machine. He did the pattern to learn Ernie’s “Easy Square Emerald” cut. Bill Wood finished a lovely round brilliant synthetic ruby on his Facetron. Good job, everyone. Thanks to all who participated.