How to Make Cabochons From Glass or Stone: Cabbing Tutorial
- Cabbing Safety
- How to Cut a Stone Slab for a Cabochon
- How to Trim Your Cabochon Preform
- Learn about Lapidary Grinders
- How to Dop Mount the Preform
- How to Rough Grind Your Cabochon
- How to Shape Your Cabochon Dome
- How to Sand Your Cabochon
- How to Pre-Polish Your Cabochon
- How to Put a Final Polish on Your Cabochon
- How to Polish the Back of Your Cabochon
When I first learned how to make cabochons, the process captivated me and I spent countless hours grinding and sanding in the dusty shop at the back of the gem shop an hour away from home. This simple technique, known as "cabbing," allows you to create a beautiful gemstone at home. Since then, I've crafted many cabochons from glass and stone using various tools and methods.
In this tutorial, SUVA has teamed up with Sean from Eckel.Lapidary to teach you the process to make your own cabochons and begin right away. Sean is a master of cabochon cutting, professionally creating top-shelf, mirror-shining gemstones for use by jewelers and in showcases. Watch Sean perform each step and see links to the products you need to follow along.
Ready to cut your first cabochon? Let's get started!
What is a cabochon?
A cabochon is a shaped and polished gemstone. They're commonly used for homemade jewelry and can also be crafted from pieces of solid glass.
What is cabbing?
Cabbing is a jargon term for making cabochons, also called cabs. Because this lapidary technique is easy to learn at home, it is one of the most popular methods of cutting gemstones.
What are cabochon stones?
They are usually made from semi-precious stones such as quartz, agate, jasper, chalcedony, onyx, obsidian, and others. Most people choose stones that are an interesting color.
Is it Safe to Make Cabochons at Home?
Cabochons can be safely made at home, but only if you understand what you're doing and respect the process and your equipment.
While I will cover as many safety concerns and best practices as possible, please note that this guide is not a substitute for independent self-education on all safety matters. Please take your health seriously by learning everything there is to know about the equipment you intend to use before setting up.
That said, here are some of the most important considerations I always think about when embarking on a lapidary project.
Safety is the most important thing to consider when starting a hobby involving motorized tools. Ensure all electronic equipment is plugged into well-tested and grounded outlets. I also recommend the following:
- Set machines up on a flat and sturdy surface
- Unplug machines whenever they are not in use, especially before making modifications
- Take precautions to keep water away from electric motors
- Thoroughly read and understand all guides or manuals before using equipment. You can download manuals for most equipment purchased from SUVA near the bottom of each product page.
You may have noticed that a lot of preparation goes into this! Fortunately, it's not rocket science. You can probably read through the average lapidary equipment manual in less than thirty minutes, and doing so will give you a much better grasp of the tools you're using.
Personal Protective Equipment
Personal protective equipment plays a crucial role in safety when working with lapidary machines. While it is unlikely as long as you follow best practices, the process may produce dangerous glass or stone shards and dust.
To avoid any damage to your eyes, skin, and lungs, please:
- Wear full safety goggles, gloves, and a filtered respirator
- Avoid wearing any loose clothing or jewelry that could get caught in the machines
- Ensure you are not fatigued or distracted while operating machinery
While lapidary is an enjoyable and useful hobby, you are using powerful machines and it should not be taken too casually. Put your safety first and you'll be more likely to avoid potential problems.
Other Safety Considerations
Remember not to use the diamond wheels while dry, and ensure everything is properly cared for and stored when not in use. When preparing to learn how to make cabochons, safety should be your primary concern.
How to make a cabochon from scratch
Whether you want to make a glass cabochon or shape a chunk of stone, this step-by-step method can be applied. Be sure to consult the image and video content provided.
Choosing the Right Material For the Job
There are two main types of materials used for cabochons: glass and stone. Each has its advantages and disadvantages. Here's how to decide which material works best for each job.
Stone cabochons are usually made from semi-precious gems such as quartz or agate. These stones are harder and more durable than glass. They are available in a wide range of colors and patterns. The downside is that they are harder to work with than glass.
Glass cabochons are cut from a single piece of glass. They are relatively easy to work with and come in a variety of shapes and sizes. However, they tend to be fragile and break fairly easily.
How to Cut a Slab From a Solid Stone
Prepare your slab saw and vice, and then clamp your chosen cabochon material in the jaws of the vice. If the rock does not take up the entire vice, it's important to balance it out with something else such as wooden blocks.
Ensure Proper Blade Alignment
If the stone pushes the slab saw blade sideways upon contact, it's important to carve a shallow groove in the rock before beginning the full cut. Doing so will give the blade a path to follow so that you will avoid creating a crooked cut and potentially damaging your saw.
Ensure the Slab is Not Too Thin
While you don't want an extremely thick slab, if it's too thin it will be difficult to work with in future steps. In most cases, 0.25 inches (~6mm) is an ideal slab thickness but it may depend on the material value and final size cabochon you are planning. A large cabochon can benefit from a thicker preform to allow a taller and wider dome.
Once you've cut a solid slab, it's time to plan the shape of your cabochon.
How to Plan the Stone's Shape
To plan the shape of a stone cabochon, I recommend using stencil templates and stone marking scribes. As a cheaper alternative, you can cut shapes out of thick paper and use sharp scissors to mark the outline.
Cabochon templates are often made of flat, lightweight plastic. Since not every part of the stone slab will look the same, placing a template over the surface can help show you what your finished cabochon might look like.
Slide the template around the stone's smooth surface, turning it different ways to see how it looks at different angles. Once you find a spot you like, use a stone marking scribe to trace the outline so you can remove the template.
Stone Marking Scribes
Stone marking scribes are pencil-shaped instruments that allow you to make marks on the stone that won't wash off during the cutting and cabbing process. Once you have clearly marked the cabochon outline to highlight the stone patterns and shape you desire, it's time to trim the cabochon preform from the slab.
How to Use a Trim Saw to Cut the Preform
A trim saw is a smaller tool that cuts away excess material until only a rough outline of the desired shape remains - the preform. Remember that you can't cut curved or bent lines - these saws only cut straight. To cut complicated or curved preforms you would need to use a Diamond band saw like the Inland DB-100.
Use the trim saw to carefully cut pieces away until you have something that resembles the shape you want. Final shaping can be done with the cabbing machine in the next step, but you want to at least get it close to the right look.
Remember that you can only make the cabochon smaller, not bigger, so I recommend cutting a little outside the lines and then finishing the shape with the lapidary grinder.
Lapidary Grinders (also known as Cabbing Machines)
Lapidary grinders are used to smooth and polish gemstones. These machines consist of multiple rotating wheels mounted on the machine's body. There are different styles of lapidary grinders, but they all share similar features and functionality.
Diamond Pacific is a top-rated lapidary brand and is well known by most hobbyists. Their 8-inch Titan Gem Maker is an industry standout, and their Genie Gem Maker provides an excellent 6-inch option. Finally, the Pixie is a portable machine with cost-effective 4-inch accessories.
CabKing and Hi-Tech Diamond
The CabKing and High-Tech Diamond brands produce excellent cabbing equipment as well, and they are focused on providing more affordable options. Their eight-inch or CabKing Cabbing Machine is a great way for new lapidary enthusiasts to get started with a full 6-wheel machine and still have some funds for slabs. Hi-Tech Diamond's Slant Cabber and All-U-Need use lapping discs and only take up about half the space of a full six-wheel lapidary grinder if you need to cab with something for even smaller spaces.
How to Mount and Handle the Cabochon Preform
One way to grind, shape, and polish the preform into a finished cabochon is called dopping. This is great for projects where you need to create details with the diamond lap. Trimming is an important step in the process in order to create the general shape you're seeking.
What is Dopping?
Dopping involves adhering the stone to a stick with special wax or glue. With the stone attached to a wooden or metal dopping stick, you can control it without being too close to the machine and potentially touching the wheel with your fingers. Dopping also makes it easier to shape round and oval cabochons as the stick can be twirled between the fingers.
Dopping requires three separate elements; a dop stick, dop wax, and a dop pot to heat the wax. You also have the option of using Diamond Pacific's Dop Master System to make switching from one stone to the next easier. Be sure to watch the video for more information.
How to Grind and Shape the Cabochon
Whether you dop your stones or not, remember to wear your safety gear any time that dust or particles might come off the stone. Also, remember never to use the cabbing wheel dry - they should always be kept damp by the geyser positioned beneath or overhead water supply depending on your choice of arbor.
Once your preform and cabbing machine are ready to go, it's time to craft the final form of your cabochon. Start with the left-most grinding wheel of your machine, which will be the most coarse, and work your way to the right.
The first two wheels are primarily used to refine your preform and shape the lower edge of the cabochon, called the girdle. It's essential to have the girdle at a slight angle to make it easier to set in jewelry - a 10-15 degree angle is ideal for most jewelers. A Diamond Pacific cab rest cuts a 12.5° girdle, while a Genie or Pixie's trim saw attachment has a block for a 10° girdle.
Before you move on from the second wheel, use it to make a small 45-degree bezel incline around the base toward the cabochon back. If this bottom edge remains sharp it will be fragile and prone to chipping, so adding the reverse bezel is an important step.
Shaping the Cabochon Preform
The remaining diamond sanding wheels, usually resin-based, are used for smoothing and shaping the cabochon into a beautiful dome.
How to Shape the Dome
Shaping the dome is how you give the cabochon its final shape before moving on to fine sanding and polishing. Remember that it's important for the back side of the cabochon to be flat so it can be easily set in necklaces or other jewelry. You will grind the dome in layers, first grinding to the desired bezel height then refining the top half of the dome in a second pass.
Finer Points of Fine Grinding and Sanding
Before moving on to the last three wheels, I recommend turning off the machine, drying the stone off with paper towel, and examining it under a good light source. The previous steps may have some remaining scratches, and they can lead to defects in the cabochon if these aren't smoothed down before the next wheel.
The reason I recommend using clean paper towels is that a cloth or brush could potentially leave moisture behind that would fill in scratches making them invisible.
It's important to go over every part of both the girdle and the dome with every wheel to ensure there are no flaws or defects.
You can use your overhead lighting to check for a uniform dome, making sure there is no deforming of your bulb's reflection over as you move your cab around during inspection.
Making Things Smooth and Putting On the Polish
The final three wheels on the cabbing machine will put a progressively fine polish on the stone. You can get creative here but overall I recommend using long smooth strokes to create a smooth and uniform shape.
If you are cabbing softer stones like turquoise or Fordite, you will find even finer-yet grit wheels to be necessary to obtain a good final polish. You will be able to use 8,000 through 50,000 grit wheels to perfect your pre-polish.
You can even equip your Diamond Pacific Cabbing Machine or CabKing with a spare shaft to quickly change out your choice of additional wheels without having to disassemble your mounting nut!
Final Steps and Considerations
Congratulations on making it this far! You're on the home stretch. Make sure you safely shut down your machines and clear your workspace before moving on to the last step.
Add your final polish with your choice of a no-mess spin-on screwback Cerium Oxide Nova lap, or use your favorite polishing compound such as diamond, tin oxide, or cerium oxide on a canvas disc or felt pad which can be attached to the right-hand side of your cabbing machine. Mix a small amount of polish with water or oil to create a thin slurry to work into your choice of pad.
If your cabbing machine doesn't support spin-on end laps, you can mount a cerium-charged wheel to make your final polish quick and mess-less! Work over the entire shape of your cabochon to achieve a final glassy shine.
Removing the Cabochon From the Dop Stick
The easy way to remove the dopping wax and separate the stick or screw from the stone is to put the stone on the edge of the warm dop pot. This will heat the stone and soften the wax enough that it can be easily scraped away.
Polishing the Cabochon Back
For many stones, especially if the jeweler will be leaving a window on the rear finding or if the material is transparent, you should always polish the backside of the cabochon for a professional finish of the perfect gemstone. Magnetic lap systems make the job quick and easy, with a range of fast-change magnetically-attached discs available from hard-plated laps for initial flattening before cabbing to magnetic Nova laps covered with a grid of the Diamond Pacific resin-bond compound. Work over the cabochon back with a similar sequence of diamond grits as you used for the top, and you'll be rewarded with a shiny cabochon sparkling on all sides with a perfect polish, ready for a delighted jeweler to incorporate into the next finished jewelry piece.
I hope you found this tutorial helpful! Remember to always put safety first when working on lapidary or other projects. Check out the Lapidary 101 Library for more tutorials of other gemcutting disciplines.
If you're looking for premade stone or glass cabochons, you may find something relevant among the great products featured on this page.
Frequently Asked Questions
If you still have some questions about cabbing, hopefully I'll answer them here.