CabinHouse TradingPost will soon offer a wide range of Lapidary Equipment and Supplies!  This will include rotary rock tumblers, lapidary trim saws, diamond blades, polishing grits, polishing compounds, epoxy and filler, dop wax and tools, grinding wheels, sanding and polishing belts, polishing drums, discs, rockhound tools, and lapidary replacement parts.  Identification and instructional books for the lapidary hobbyist and the lapidary professional will add to this list.

Lapidary Equipment

Rotary Rock Tumblers - Lortone Rotary Rock Tumblers are among the best on the market.

     ● 3 Lb Capacity Lortone Model 3A

      ● 2 - 3 Lb Capacity Lortone Model 33B (double barrel)

Lapidary Supplies

Tumbling Grit and Polishing Kits - 4 step polishing grit kits for rotary rock tumblers are a great way to save.  Everything you need to grind and polish up to 10 lbs of rock in your rotary rock tumbler.

     ● MLS Regular Sized Grit Kit for Rotary Tumblers with Special TXP Polish!

As with all minerals and stones, while cutting, handling, and polishing use caution.  Washing hands and wearing
face masks are always good ideas when working with any stone materials!  Filtration and exhaust systems are an added bonus to health and safety!

Lapidary Tips for cutting and polishing cabochons

Some cabbing rough is randomly fracturous by nature.  Cuttings from larger stones may tend to be more stable.
Patience while working with any stone material is key.  Stabilized materials are acceptable, but untreated stone may need to be treated for acceptable results.

Equipment

Diamond and Silicon Carbide - The common theme is that diamond is faster and silicon carbide is cheaper.

Silicon Carbide

Silicon Carbide is more tolerant of abuse and works great for materials at a MOHS 7 or less.  The grinding wheels of carbide are better for grinding larger, rougher stones.  Occasionally, silicon carbide grinding wheels need to be trued or dressed with a diamond dressing tool.  A "true" wheel eliminates bumping during grinding or sanding.  For sanding wheels, I feel expanding drums are the best for silicon carbide belts.  A supply of silicon carbide belts should range from 220 grit up to 600 grit.  The downside is wear.  Silicon Carbide belts will wear much quicker than diamond.  Diamond belts are also useful at times on an expanding drum to achieve that final result.  Typically, stones shaped and sanded with silicon carbide will be polished with a compound on a buffer, leather wheel or disc.
A worn silicon carbide belt can still be used to receive a polishing or smoothing finish.  Silicon Carbide works great on silver and other metals.

Diamond

Diamond wheels are designed to operate on a machine with extremely true arbors.  Diamond is less tolerant of bumping due to extremely rough material.  Diamond is also necessary for harder materials of MOHS 7.5 and up.  Diamond wheels and belts will make work faster and easier, but care is critical.  A good water or coolant flow must be available at all times.  Avoid gouging edges into the wheels or belts.  With patience and proper care, diamond will outlast any silicon carbide.  The higher cost can be offset by the amount of usage diamond can receive.  A six wheel cabbing machine may have two grinding wheels of 100 grit and 360 grit, with four sanding wheels of 600g, 1200g, 8000g, and 50,000g.  With harder stones, a mirror polish can be easily attained with the diamond wheels alone.
I sometimes polish my finished pieces on a 50,000g diamond belt on an expanding drum on my silicon carbide machine.

Preparing the Stone

Most slabs will cut easily on a small trim saw when trimming for cabs.  As with all stone, especially Tiger Eye, opalites, etc., care and patience is important.  The finished appearance is determined by the style of jewelry in which it will be set.  For porous material, an Opticon treatment may be needed to get the mirror finish desired or to fill small pits.  The use of Opticon is an acceptable practice.
This is not the case with higher grades.  Higher grade materials are stable, but will cost more.
Always experiment and learn using lesser valued materials.

Small stones may be slabbed on a trim saw.  A trim saw would be described as a small unit with a water reservoir and a 4 inch to 6 inch blade driven by a small motor.  Most trim saws are used with the hands of the cutter holding the stone in place of a vice.  Slabbing small stones on a trim saw require patience.  Be particularly attentive to the consistent width of the slab.  Slabs for cutting cabochons should average of 8mm.  Slabs 9mm or10mm are great for high dome cabochons or wire-wrap cabochons.  6mm or 7mm are fine for smaller ring size cabochons. Purchasing pre-cut slabs is a convenient way to acquire cabochon cutting material.

With slab in hand, you are now ready to determine the cabochons the stone will yield.  This includes how many, sizes, shapes, etc.  Professional cutters desire to create as many cabochons with as little waste as possible.  Study your piece.  See the patterns and colors and let them tell you how to cut out the finished pieces.  Templates are a good way to lay out cabochons on a slab.  Freehand design for the artistic person is the method used for freeform cabochons.  Either way, you will soon discover the design methods you prefer as well as your ability to finish out a difficult design with you equipment.

Personally I love to work with long and short ovals from a template.  My freeform cabochons are usually a result of randomly shaping a small slab or a leftover piece cut off from a slab.

Now that you have marked off the designs you want for your cabochons, take the slab to the trim saw.  Begin to carefully cut out the templates for grinding.  Laying out cabochons on a slab and cutting them out is a technique you will best discover for yourself.

Grinding Your Cabochon into Shape

Many cutters use dop sticks to work their cabochons.  Learning to use dop sticks as well as the proper wax is through experimentation.  I use a green wax with wood dowel sticks of various diameters based upon the size the cabochon will be.  The dop stick is an extension of your hands and it is easy to develop a style which will work for you.  Although, I make most of my cabochons with my fingers, the sticks will save your nails as well as give you an ease of use from start to finish.  Follow the instructions from your dop kit!

Always be sure you have an adequate water supply to your grinding and sanding wheels.  keep your cabochon at just below the center of the wheel to assure a smooth grind or sand.

When preparing the trimmed piece on the grinding wheel, begin with a 220 grit silicon carbide or 100 grit diamond wheel.  Preferred is a six inch diamond, but Silicon Carbide will work well as long as the wheel is true to round and does not bump against the stone.  Be patient in grinding and shaping.  Once you have prepared the shape, begin your bevels for sanding.  Proceed with sanding through all wheels right up to a finish sanding.  Six inch diamond wheels are best moving from 600 to 50,000.  Silicon Carbide belts will work fine moving from 220 through 600.  If using silicon carbide, it may be necessary to use a polishing compound for final polish, such as tin oxide on leather, diamond compound, or Zam preceded with Tripoli.  Keep it wet when using sanding wheels or compound powders!  With some materials, heat will tend to help the polished finish.  Experimentation is key!

● Grinding / Shaping

Always begin with your coarsest wheel.  If grinding on this wheel proves to rough or if too much chipping is evident, move up to the next wheel.  Slowly rotate your template on the wheel grinding to your template mark layout.  Now once your cabochon has taken shape, begin preparing your dome.  Starting from the outside edge, begin a 45 degree bevel.  Work this bevel down until you have slight rim at the base.  Once this is complete, starting at the top edge of this 45 degree bevel, begin another bevel working down to where you have only slight rim left on your first 45 degree bevel.  Continue with each bevel until you reach the center.  Often only two bevels are necessary to achieve a great dome.  At the base of your cabochon grind a slight bevel on the outside edge.  This is called the bezel edge.  This will prevent chipping at the base and allows easier setting into the jewelry bezel piece.

● Sanding

Beginning with your coarsest sanding wheel or belt, work your way up through to your final wheel or belt.  Before moving to each wheel or belt closely examine your piece for an even sanded surface.  If areas of scratches are still evident, you will need to move back down to a lower sanding wheel or belt to remove the scratches before proceeding.  Magnification lenses or lamp are great for seeing these scratches.  Always be patient and thorough.  Once you have completed your final sanding on your finest wheel or belt, examine your cabochon.  If you have a mirror finish you are done!  Great job!

Some material may require a final polishing compound such as Zam.  Powdered compounds such as 50,000 diamond on leather are necessary on some materials.  Experimentation is key!  Keep a book of notes on different materials and there needs.  As you develop experience, much will become natural!

Treatments for a Great Polish

All quality cutters have Opticon or 330 resin in there supply storage.  Using Opticon or 330 is an acceptable practice among many high end
cabochon cutters.  In some cases, it may be necessary to apply either for stability or for a final polished finish.  Use 330 to stabilize your cab
starters and Opticon to stabilized the surface.  This will give an added bonus, but may not be necessary, as long as patience is used
when grinding and sanding your cabs, except for porous material.  Always read and follow instructions for use.  Like all cutters, the fun is in experimentation!

Lapidary Tips for polishing rocks with rotary rock tumblers

Select stone for tumbling that are generally 3/4 inch diameter and smaller.  A few larger stones may be polished in a load that consists primarily of smaller stones.  Proceed as follows:

Step 1 -  using MLS 60/90 mesh COARSE Silicon Carbide Abrasive:  Fill tumbler barrel approximately 3/4 inches full of rock.  Add 1 1/2 ounces of course grit for each pound of rock.  Add water to within approximately 1 inch of top of rocks (below not over).  After a few hours of running, the grit and water should form a thick, creamy slurry.  Add or remove water as necessary to achieve this consistency.  Run continuously for 7 days.  Occasionally open the barrel to check and maintain the slurry.
Note: 1 ounce Course = 4 level tsps.

Step 2 - using MLS 150/220 mesh MEDIUM Silicon Carbide Abrasive:  Remove rock and slurry from barrel.  Thoroughly clean and rinse rocks and barrel.  If possible, use a separate barrel for each stage.  Return rocks to barrel and proceed as in Step 1 adding 1 1/2 ounces of medium mesh per pound of rock.
Note: 1 ounce Medium = 4 level tsps. plus a little

Step 3 - using MLS 500F mesh FINE Silicon Carbide Abrasive:  Remove rock and slurry from barrel.  Thoroughly clean and rinse rocks and barrel.  If possible, use a separate barrel for each stage.  Return rocks to barrel and proceed as in Step 1 and 2 adding 1 ounce of "fine" mesh per pound of rock.
Note: 1 ounce of Fine = 8 level tsps.

Step 4 - using TXP Polish:  Remove rock and slurry from barrel.  Thoroughly clean and rinse rocks and barrel.  If possible, use a separate barrel for each stage.  Return rocks to barrel and proceed as in Steps 1,2, and 3 adding .08 ounces of TXP polish per pound of rock.  Addition of plastic pellets will help cushion the tumbling action and help achieve a better polish.

Step 5 - using Ivory Soap:  For an extra high polish, clean rocks and barrel again and add some shavings of Ivory soap.  Add water to within 1 inch of top of rocks and run for 3 to 6 hours.  addition of plastic pellets will help cushion the tumbling action and provide a better polish.  Remove rocks, rinse and lay out on a towel to dry.  Using a "soap" can create a "gas" pressure.  It may be necessary to open the container a couple of times within the first hour to alleviate pressure.

Additional Tips:
● DO NOT empty slurry into household drains.  It hardens into a concrete like substance!
● For best results, clean every speck of grit or mesh from rocks, barrel, lids, and gasket after each step, especially before rocks are put into polishing cycles.  Clean and rinse each rock (a strainer is useful).  Use a toothbrush to clean out crevices.
● Preceding guidelines are great for "agate" type stones.  It also works great with "opalite" stones.  Sometimes it is useful to have additional polishes for certain rock, such as "tin oxide" or "cerium oxide".  Use plastic pellets in later stages.
● Addition of a small amount of "soda bicarbonate" will help eliminate gas build ups causing unwanted pressures with certain meshes and polishes.
● Stones with a hardness of 5.5 MOHS and up work well for tumble polishing.  Softer stones, such as turquoise, may only need as little as 24 hours each step.
● Experiment and have fun!

For more help, information, references, or tips Contact CabinHouse TradingPost!