“How thick should a medal be” sounds like a style question, and most suppliers answer it like one — 3 mm is standard, 4 mm is premium, pick one. In a die-casting plant it is not a style question at all. Thickness decides whether the mold fills, whether the part comes out without cracking, how deep your relief can go, how long the piece spends in the plating line, and what it costs to fly 5,000 of them across an ocean. We cast medals every day in Huizhou, and the thickness conversation is usually the one that saves buyers the most money. If you are still working out what the rest of the medal is made of, start with our custom medals overview; this article is about the one dimension that constrains everything else.
Why 2 mm Is a Physical Floor, Not a Commercial Choice
Buyers sometimes ask us to quote a 1.5 mm die-cast medal to save weight or cost. We cannot, and it is worth explaining why in mechanical terms rather than just saying no.
Reason one: the metal freezes before it fills. Zinc alloy melts at about 385°C and is injected into a steel mold on an 88-ton press. The cavity is thin, the mold is cold relative to the melt, and the alloy loses heat the moment it touches steel. At 2 mm the metal still has enough thermal mass, and enough pressure behind it, to reach the far edge of the cavity before it solidifies. Below that the flow front stalls: you get a short shot, a rounded, unfilled edge, or lettering that reads as a blur.
Reason two: the ejector pins need something to push. Once the part solidifies, ejector pins push it off the mold. Those pins act on a small area and the force is concentrated. At 2 mm there is enough material to take that load; below it, the pins dimple or punch through the back. This is the same mechanism behind the cracks listed in our defect guide — pins that are too few or unevenly spaced load the part unevenly and crack it.
So 2 mm is where the process stops working, not where the pricing starts. In practice we cast between 2.5 mm and 4 mm for most programs, and treat anything above that as a separate engineering conversation.
Thickness to Weight: The Table Buyers Actually Want
Weight is the visible consequence of thickness, and it is easy to estimate before a sample exists. Zinc alloy has a density of 6.7 g/cm³. Multiply the face area by the thickness and you get the flat-plate weight — the weight of a solid disc with no relief, no cut-outs, and no ribbon.
| Thickness | 50 mm round (flat-plate) | 60 mm round (flat-plate) | How it feels in the hand | Typical use |
|---|---|---|---|---|
| 2 mm | ~26 g | ~38 g | Light; thin edge, sharp silhouette | High-volume finisher medals, tight budgets |
| 2.5 mm | ~33 g | ~47 g | Light but solid; the volume default | Race and event medals at scale |
| 3 mm | ~40 g | ~57 g | Balanced; reads as a real award | Most podium and school medals |
| 4 mm | ~53 g | ~76 g | Noticeably substantial | Championship, corporate, commemorative |
| 5 mm | ~66 g | ~95 g | Heavy; wants a wider ribbon | Statement pieces, small quantities |
| 6 mm | ~79 g | ~114 g | Very heavy; a display object | Ceremonial and collector pieces, quoted individually |
Two caveats, both important. First, these are flat-plate figures: real medals carry relief, so the average section is thinner than the nominal thickness and the actual piece weighs less — often meaningfully less on a design with a deep central boss and a thin field. Second, the ribbon and hardware add weight on top. Use the table to compare options, not to predict a shipping manifest.
The same math explains why diameter matters more than buyers expect. Weight scales with the square of the diameter but only linearly with thickness, so going from 50 mm to 60 mm adds more mass than going from 2.5 mm to 3 mm.
| Diameter at 3 mm | Face area | Flat-plate weight | What changes |
|---|---|---|---|
| 40 mm | 12.6 cm² | ~25 g | Compact; detail must be simplified |
| 50 mm | 19.6 cm² | ~40 g | The workhorse size for events |
| 60 mm | 28.3 cm² | ~57 g | Room for a crest plus text |
| 70 mm | 38.5 cm² | ~77 g | Statement scale; heavier ribbon required |
| 80 mm | 50.3 cm² | ~101 g | Display scale; check attachment rating |
What Each Step Actually Buys You
Thickness is not a smooth dial. Each half-millimetre changes something specific.
2 mm is the minimum that casts reliably, and a legitimate choice for very large runs where the medal is a token rather than a trophy. The limitation is not strength — a 2 mm zinc disc is tough — it is depth: there is almost no room for a raised figure.
2.5 mm is where most of our volume sits. It gives enough material for a 0.6–0.8 mm relief field, survives plating without edge thinning, and keeps freight sane on orders in the tens of thousands. For a race medal handed to every finisher, this is usually the right answer.
3 mm is the step where a medal starts to feel like an award rather than a token. It supports deeper relief, a recess deep enough for hard enamel polishing, and an edge thick enough to look deliberate from the side. If the medal is going on a podium, 3 mm is the floor we recommend.
4 mm is a deliberate weight statement. It changes the sound the medal makes when it lands on a table, which is a real part of perceived value. It also costs more in three places: metal, plating time, and freight.
At 5 mm and above the piece moves out of the wearable category and into the ceremonial one. The mold has to be engineered for it, the ribbon has to be rated for it, and shipping becomes a line item you notice.
| Thickness | Relief depth available | Recess for enamel | Plating behaviour | Relative cost pressure |
|---|---|---|---|---|
| 2 mm | Very shallow, ~0.3 mm | Shallow; soft enamel only in practice | Fast; low surface area | Lowest metal, highest handling risk |
| 2.5 mm | ~0.6 mm comfortable | Soft enamel; hard enamel possible | Standard | Baseline |
| 3 mm | ~0.8 mm comfortable | Soft or hard enamel both work | Standard | Slightly higher metal |
| 4 mm | 1.0 mm and above | Deep, polishable recess | Longer dwell, more drag-out | Higher metal and plating cost |
| 5–6 mm | 1.5 mm and above | Deep; suits thick fills | Needs rack adjustment for weight | Quoted case by case |
Thickness and the Plating Line
Plating is a surface process, so a thicker medal is not automatically harder to plate — but it is not free either.
The nine-step cycle starts with degreasing and ultrasonic cleaning, then alkaline copper for about 500 seconds as the adhesion layer, then acid copper for 20–60 minutes for leveling and brightness, then the color metal, then a tunnel oven at 100°C for 40 minutes. None of those timings are set by thickness. What thickness changes is the surface area per part and the geometry the current has to reach.
A 4 mm body has more edge area than a 2.5 mm body of the same face size, and edges are where plating builds fastest. That is why heavy medals can show a bright, almost burnished rim if the rack is not set up for them. Deep recesses on a thick body are the opposite problem: the color metal deposits thinly at the bottom of a narrow channel because the current density there is low. Thicker bodies let you cut deeper recesses, which is good for design and less forgiving for plating. Our plating and surface finishes guide covers how the finish route itself is chosen.
The cost consequence is straightforward: more surface area means more chemical drag-out, more rack weight, and slower handling per hundred pieces.
Thickness and Color Fill
Enamel sits in recesses, and recess depth follows body thickness. On a 2 mm body there is little room to cut a recess and still leave a structural floor, so color sits shallow and the metal lines dominate. At 3 mm or 4 mm the recess can be deep enough for imitation hard enamel, which is filled, polished flat, and then plated — a reverse process that only works when there is enough material to polish without cutting through. Minimum color width does not improve with thickness, though: 0.3 mm for soft enamel, 0.5 mm for hard and glass enamel.
Thickness, Ribbon, and Wearability
A medal is worn, not just held, and the ribbon has to carry the mass. Standard heat-transfer ribbon runs 860–900 mm long and 20–30 mm wide, with a shorter 800 × 20 mm ribbon for kids’ events.
As a working rule in our sampling room, a 2–2.5 mm medal at 50–60 mm sits comfortably on a 20 mm ribbon, a 3–4 mm medal wants 25 mm, and anything at 5 mm or above should be on 30 mm with a heavier attachment. A narrow ribbon on a heavy medal does not fail immediately; it twists, then the weld at the fold takes a concentrated load, then it starts to peel.
Attachment hardware has the same relationship. Split rings, safety pins, screw posts, ball chains, and magnets from 2 mm to 20 mm all have practical load limits, and a 100 g medal on a small split ring is a warranty claim waiting to happen. Our medal ribbons page covers ribbon and fitting options together.
6 mm and Above: Why It Gets Quoted Separately
Once a medal passes roughly 6 mm, the physics changes and the tooling has to change with it.
Solidification and shrinkage. A thick section cools unevenly: the skin freezes first, the core later, and the contraction that follows pulls the face inward. The result is a sink mark on the show face — a shallow depression that is invisible before plating and obvious after, because plating is a mirror and mirrors exaggerate every curve.
Cycle time. Thick parts stay in the die longer before they are rigid enough to eject, which reduces shots per hour — a direct cost. Ejection also needs more force, which raises the chance of marking the back.
Weight downstream. A 6 mm, 70 mm medal is roughly 90–100 g before the ribbon. On a 2,000-piece air shipment that is a real freight line, and on a ribbon it is a real load.
None of this makes thick medals a bad idea — just a different project. If you want a heavy look without the engineering, the cheaper lever is diameter, not thickness: a 70 mm medal at 3 mm reads as substantial and weighs about what a 60 mm at 4 mm does, with a fraction of the casting risk.
How to Specify Thickness Without Guessing
The useful way to brief a factory is not “make it 3 mm,” but five inputs:
- Diameter or longest dimension in millimetres.
- Maximum relief height — how far the highest element stands off the base plane.
- Target weight, if the medal has to feel a certain way in the hand.
- Quantity, because it decides how much tooling cost can be absorbed per piece.
- The use case — worn for two hours at a race, handed to a sponsor, or displayed on a stand.
With those five the thickness usually chooses itself; without them you get a default. We turn artwork and those inputs into a production-ready proof within 24 hours, and the proof states the thickness we recommend and why, so the decision is documented before the mold is cut.
The Cost Structure Behind the Number
We do not publish unit prices: the honest answer depends on quantity, design, finish, and packaging, and any number quoted without those is fiction. What we can explain is the structure, because it tells you which lever to pull.
| Cost driver | How thickness affects it |
|---|---|
| Metal | Scales directly with volume — a 4 mm body uses roughly 60% more alloy than a 2.5 mm body of the same face |
| Mold | Thicker sections need more cooling and stronger ejection; deep draws cost more to cut |
| Casting cycle | Thicker parts stay in the die longer, so fewer shots per hour |
| Plating | More surface area and more rack weight per hundred pieces |
| Ribbon and hardware | Heavier medal requires a wider ribbon and a stronger fitting |
| Freight | Weight and carton dimensions both rise |
The only reliable way to compare is a quote at your actual quantity, because tooling amortizes and the per-piece picture changes with volume. That is why we quote by quantity tier rather than quoting a single number that would only be true at one order size. Our design guide covers the artwork side of the same conversation.
FAQ
How thick should a custom medal be? For most programs, 2.5–3 mm. That range gives enough material for real relief, survives plating cleanly, and keeps freight reasonable. Go to 4 mm when the medal has to feel substantial in the hand, and stay at 2–2.5 mm when volume and shipping cost dominate.
Why can’t a die-cast medal be thinner than 2 mm? Because the alloy freezes before it fills. At 2 mm the metal still reaches the far edge of the cavity before solidifying; below that you get short shots and blurred detail. The ejector pins also need enough material to push against without dimpling the back.
Does a thicker medal weigh proportionally more? Yes, almost exactly — weight is density times volume, so doubling thickness roughly doubles mass at the same diameter. Zinc alloy is 6.7 g/cm³, so a 60 mm round at 3 mm is about 57 g as a flat plate before relief is cut into it.
Is a heavier medal better quality? Not automatically. Weight signals substance and recipients read it that way, but a heavy medal with a thin plating stack will look worse in a year than a light one with a proper finish. Thickness and finish are separate decisions and both have to be right.
Can I get a thick look without the weight? Often yes — increase the diameter instead. A larger medal at 3 mm reads as substantial while carrying far less casting risk than a small medal at 6 mm, and it usually costs less in metal and freight.
Do thick medals take longer to produce? They take longer to cast per piece, because a thick section stays in the die until it is rigid enough to eject. We still quote samples at 7–10 days and bulk at 7–15 days, but the schedule is set after thickness is confirmed.
Pick the Thickness Before the Mold
Thickness is one of the few decisions that is genuinely hard to reverse. Once the tool is cut, the body is what it is; plating, color, ribbon, and packaging can all change on a reorder, but the casting cannot. That is why we would rather spend an hour on this at the artwork stage than discover a sink mark on a 5,000-piece run.
We have been casting medals since 2010, run 30,000+ pieces a day, export to 50+ countries, and hold a 100-piece minimum per design with three-stage QC and 100% conforming delivery. Send us your artwork with the diameter, the relief height, and the quantity, and we will come back with a recommended thickness, a weight estimate, and a quote by quantity tier. Contact us with the details, or read the five-layer breakdown first if you want to understand what sits on top of that body.
