One of the first questions we ask when a client brings us a bold ring, a chunky cuff, or an oversized pendant is simple: does this piece need to be solid? Hollow jewelry design in CAD is one of the most effective tools we have at eCadCam for reducing metal weight and casting costs. With gold and platinum prices where they are, the difference between a solid and a hollowed design can be hundreds or even thousands of dollars per piece. Here is how we decide when to hollow a design, how we do it, and what it means for durability.
Why Metal Weight Drives the Cost of Custom Jewelry
In lost-wax casting, metal is usually the single largest line item on a custom piece. Design time, wax printing, and casting labor are relatively fixed, but metal cost scales directly with volume. Every cubic millimeter of a CAD model becomes a cubic millimeter of gold, silver, or platinum. A wide statement ring modeled as a solid block can easily weigh 20 to 30 grams in 14k gold, while the same silhouette with a properly hollowed shank and underside might come in at 10 to 14 grams.
Weight also affects wearability. A heavy pendant pulls on a chain and flips; a heavy earring sags the lobe; a thick solid ring feels clumsy on the hand. Hollow jewelry design keeps the visual presence of a large piece while making it comfortable enough to wear every day.
How We Hollow a Jewelry Design in CAD
Hollowing is a decision we make inside the CAD model, not an afterthought at the bench. Our workflow starts with the finished exterior form, then works inward.
Shelling and Back-Cutting
For rings, cuffs, and bangles, the most common approach is back-cutting the underside. We remove material from the inside of the shank and the back of the head while leaving a uniform wall, typically 0.8 to 1.2 mm for gold and silver and slightly thinner for platinum thanks to its strength. The outer surface and all visible edges stay exactly as designed. On pendants and large charms, we often shell the entire back and add a flat or slightly domed back plate so the piece reads as solid from the front but weighs a fraction of a solid casting.
Fully Enclosed Hollow Forms
Large beads, domed earrings, and sculptural forms can be modeled as fully enclosed shells. These need at least one small vent hole so the castable wax or resin can drain during printing and so investment and gases can escape during casting. We place these holes where they are hidden, such as under a bail or inside a post. A fully enclosed form with no vent will trap material and almost always fail at the casting stage.
Hollow vs. Solid: When Solid Is Still the Right Choice
Hollow jewelry design is not a universal answer. Some pieces should stay solid, and we tell clients when that is the case.
- Thin bands and delicate pieces. If the piece is already under 2 mm thick, there is nothing meaningful to remove, and hollowing would only weaken it.
- Heavy-wear items. Men’s rings worn daily around tools or sports gear benefit from solid shanks that can be resized and polished for decades.
- Pieces that will be resized often. A hollow shank can be resized, but the cavity complicates soldering. For heirloom rings, we usually keep the shank solid and hollow only the head.
- Weight as a selling point. Some clients want the heft of a solid piece. That is a legitimate choice, and we model it accordingly.
Durability, Dents, and Minimum Wall Thickness
The main concern we hear about hollow jewelry is denting. A hollow piece with thin walls can deform if struck, and a dented hollow form is harder to repair than a scratched solid one. The answer is correct wall thickness, not avoiding hollow construction altogether. We keep walls at or above the minimums our casting process can reliably fill, add internal ribs or a thicker rim on large flat areas, and avoid hollowing anywhere that will be hammered, stamped, or laser engraved after casting. Done this way, a hollow cuff or pendant holds up to normal daily wear for years.
What You Can Expect to Save
As a general guide, back-cutting a wide ring or pendant typically removes 30 to 50 percent of the metal weight compared with a solid version of the same design. Fully shelled sculptural pieces can save more. Because we model in CAD, we can give you the exact metal volume of both the solid and hollow versions before you commit, along with an estimated weight in your chosen alloy. That lets you decide based on real numbers, and it is one reason we recommend a 3D-printed fit model before casting any large piece.
Get a Lighter, Smarter Custom Piece Made in Los Angeles
If you have a bold design in mind and want to keep the metal cost under control, hollow jewelry design in CAD is the place to start. Our Glendale studio handles the full process, from CAD modeling and wax printing to casting and finishing, and we will show you the weight of every option before anything is cast. Send us a sketch, a reference photo, or an existing piece, and request a quote from eCadCam in Los Angeles today.