Minimum Wall Thickness for Casting Sterling Silver

The single most common reason a CAD file fails at the casting stage isn't detail or complexity — it's walls that are too thin to fill. If you design in software and produce in metal, wall thickness is the number that decides whether your piece comes out crisp or comes out broken. Here's how to get it right.

Why thin walls fail

Molten silver has to flow into every part of the mold before it starts to solidify. A wall that's too thin cools too fast — the metal freezes before it fills, leaving incomplete edges, pinholes, or a piece that simply doesn't form. Even when a thin wall does fill, it comes out fragile, prone to bending, cracking, or wearing through in daily use. What looks fine on screen can be structurally hopeless in metal.

The practical minimum

As a working rule for cast sterling silver, keep walls at or above 1 mm. That's the floor for a piece that fills reliably and survives normal wear. Some features can go thinner with care — but 1 mm is the number to design to unless you have a specific reason and a caster who's confirmed it works. Related design minimums that travel with it:

• Raised detail and texture: at least ~0.8 mm of relief height to survive casting and finishing.
• Prongs and thin elements: thicker than you think — they take the most stress and the most polishing.
• Layer separation in printed masters: around 0.4 mm so features don't fuse.

How shrinkage changes the math

Silver contracts as it cools, and every step from resin master to rubber mold to final cast removes a little more size. A wall designed right at the minimum can end up under it after shrinkage. This is why a good manufacturer applies shrinkage compensation before tooling and, for a first run, casts a sample to measure the real numbers rather than trusting the theory. Wall thickness and shrinkage are the same conversation.

Designing for the finish, not just the cast

Remember that polishing removes material. A wall that's exactly at minimum before finishing can be under it after. Give hand-finished pieces — especially high-polish surfaces — a little extra so the final, polished wall still clears the floor.

Get it checked before you tool

The cheapest time to fix a thin wall is in the CAD, before a mold exists. A casting-readiness review catches under-minimum walls, insufficient relief, and shrinkage risk before they cost you a failed run. If you're preparing a file, start with how to prepare an STL file for silver casting.

Request a quote → — send your file and we'll flag any wall-thickness or shrinkage issues before we cut a mold.