Before we delve into the details, I wanted to highlight one key point: the difference between factory-made and mass manufacture. When you hear “factory”, you think “automation” and “machinery” – images come to mind of robot arms pouring melted plastic into molds on a conveyor belt. This is true for some factory-made dice, but not all – a factory might be a number of artisans all working by hand in the same facility. It all depends on the dice, as you’ll see as we go on.
In writing this, it became apparent that I had way too much information for a single blog post, so I’ve split it into separate posts; see the sidebar for an index.
I’ll be posting the upcoming parts soon, and I’ll link them here as soon as they’re up.
I want to thank Alex Abrate for his assistance with this series of posts. Alex is the head honcho of Level Up Dice, one of the best-known names in the premium dice market. When I started writing this post, I knew I wanted to include information about how premium dice are made – stone, wood, metal and more – and I knew I needed an expert. Alex kindly agreed to help and was very generous with his time and expertise. Thanks, Alex!
I’d also like to thank Donald Reents, the founder of Chessex Manufacturing, for the information about manufacturing urea dice such as Chessex’s Opaque and Speckled ranges. Urea is not a common material for making dice, and it was great to get the information right from the source. Thanks, Donald!
Some of the photos in these posts are of dice in my own collection; for others, I’d like to thank two people:
- Lena, a fellow dice goblin with some truly lovely dice; Lena kindly assisted with pictures of handmade dice.
- Melissa of the Goblin Dice Hoard Facebook group for dice collectors, who generously shared pictures of many amazing sets of premium dice.
Without further ado, on with the post!
The Basics – Casting and Carving
There are two main ways of making dice out of something, whether that’s mass-market plastic or the highest-end metals and woods:
1) Making the material malleable, and putting it in molds which are the inverse of the die design, so that when the material hardens and is removed from the mold, it’s already shaped like the die (or anything else you want to make). This is called casting. Casting is usually used for plastic (acrylic and resin) dice, some metals, and novelty materials like candy, soap, and chocolate.
2) Taking a chunk of solid material, and removing all the pieces that won’t be part of the final die. This might be via CNC milling, grinding, sandblasting, laser or machine engraving, or carving. These methods are usually used for wood, stone and some metal dice.
There are also some specialty and emerging methods (like 3D printing), but they don’t account for much of the dice market – yet. Industrial technology improves rapidly, so you never know what you’ll see for sale in a few years’ time!
How Acrylic Dice Are Made
Acrylic dice are made through an automated process – because of the temperatures involved, it’s not practical or safe for hand-makers. This means that it’s easy to make acrylic dice in bulk, and historically almost all mass-market dice have been acrylic.
Forming Acrylic Dice
Acrylic dice start their life as pellets of plastic which are melted and molded to form dice; makers choose from different plastics, depending on the desired end result. Most acrylic dice are made of PMMA (or polymethyl methacrylate) which is great for optical clarity, allowing for clear colour swirls, windowing and other multi-colour effects, whereas dice like Chessex’s Speckled range are made of urea formaldehyde, which doesn’t blend, to achieve the speckled effect.
When most people talk about “acrylic” dice, they’re referring to PMMA dice.
How Dice are Made: Post Index
- Post 1: How Acrylic Dice are Made, including the basics of dice-making. (That’s this post.)
- Post 2: How Resin Dice are Made, including handmade dice from indie and hobbyist dice makers, and a comparison of acrylic vs. resin dice.
- Post 3: How Metal and Wood Dice are Made, popular materials in the premium dice market.
- Post 4: How Stone, Glass and Other Premium Dice are Made, and when stone isn’t stone.
PMMA is a thermoplastic – a type of plastic which melts when heated, and will melt again when reheated – and most PMMA acrylic dice are created through a process called injection molding:
1) The thermoplastic is melted to a liquid, and mixed with any colourants or additives like glitter. If needed, it’s swirled or mixed to achieve the desired effect.
2) The liquid plastic is poured or squirted into a mold. The mold will usually be a slab with multiple cavities to create a number of dice at once, connected by hollow channels for the plastic to flow along.
3) The liquid plastic cools quickly, taking on the shape of the mold and hardening.
When the dice are removed from their mold, they’re still attached to the plastic which has hardened in the hollow channel; these are the sprues.
Urea formaldehyde is a thermosetting polymer – a type of plastic which can be melted to shape it, but which won’t melt a second time once it’s been hardened and cured – often used for insulation, lamination, fabrics, glues, and other practical uses. Donald Reents of Chessex describes it like this:
“Urea is good for dice because it is dense, so feels heavy when rolling, and does not contract as much when it cools as other materials so very flat surfaces can be achieved.”
Urea is an opaque material, although it can be pearlised. Chessex uses urea for their Opaque and Speckled ranges, and they’re formed using compression molding:
1) The thermoset plastic is heated to soften it, and then placed into the open mold cavity.
2) The open face of the mold is plugged or covered, and pressure is then applied to force the material to fit the mold’s shape.
3) The heated, soft thermoplastic then cools in the shape of the mold, hardening and “curing” in the process, and won’t melt if re-heated.
This method is ideal for finishes like Speckled dice, as the compression molding process doesn’t swirl or blend the colours as injection molding does.
Finishing Acrylic Dice
The dice are then stripped from their sprues (if injection-molded) and painted to fill the pips or number indentations.
Next, the dice are poured into a tumbler – rather like a large cement mixer – with polishing compounds. As the dice are tumbled, the compound scours away the excess paint, and polishes the surface to a shine; this process is also responsible for the rounded edges and corners of acrylic dice.
Sprue marks are an inevitable part of the process for injection-molded dice, and usually appear on acrylic dice as small burrs, blotches or scuffs, particularly on the edge of a die. Some dice brands take more care than others to polish away their sprue marks.
Some dice makers sell “raw” unfinished acrylic dice to hobbyist customers; these dice are unpainted and untumbled, allowing the customer to finish them to their liking.
Sprue mark on a Chessex Blue-Teal Gemini d%.
Raw acrylic dice, sanded and polished by hand, not yet inked. Black Ice by Kraken Dice, finishing by me.
Historically, acrylic dice have formed the bulk of the factory-made dice market. In recent years, though, resin dice have surged in popularity and have attracted a lot of attention. In the next post in this series I’ll be looking at how resin dice are made, and the similarities and differences between resin and acrylic dice.