Walnut Shell Tumbling Media

Walnut Shell Tumbling Media — dry polishing, cleaning and drying for jewelry, soft metals and delicate parts

Walnut shell tumbling media is a natural, angular, biodegradable dry media made from crushed walnut shells. It is used in dry tumbling — a finishing process with no water and no wet compound — where the shell grit acts as the abrasive carrier for polishing paste applied to the workpieces. The angular shape of the crushed shell creates points of abrasive contact that produce effective polishing action without the surface damage risk of harder ceramic or steel media.

The primary applications are jewelry polishing, soft metal finishing, plastic part polishing and delicate parts where water-based wet finishing would cause dimensional change, part marking or surface staining. Walnut shell media is also used as a dry drying agent — similar to corn cob media — to remove residual moisture and light contamination from parts after wet finishing without introducing new abrasive action.

• Dry tumbling — no water, no wet compound, no drying step required
• Angular crushed shell grit — effective polishing action with polishing paste
• Minimal scratch — soft enough for jewelry, gold, silver and delicate soft metals
• Mirror finishing achievable with the correct paste grade
• Biodegradable and low cost — environmentally benign, economical to use and replace
• Customisable mesh size — coarser for faster cut, finer for higher polish

At a glance

How dry tumbling with walnut shell media works

Parts are loaded into the tumbling machine with walnut shell media. Polishing paste is applied — either pre-applied to the parts or added to the media. The tumbling action causes media and parts to move against each other; the angular shell grit carries and distributes the paste across all part surfaces. No water is used at any stage. After the cycle, parts are removed already dry and polished, ready for inspection or packaging without a separate drying step.

Who walnut shell media is built for

Jewelry workshops polishing gold, silver and soft precious metals — walnut shell is the standard dry polishing media for jewelry. The angular grit is hard enough to carry polishing paste effectively but soft enough not to scratch the finished surface of gold, silver, copper and similar soft metals. Mirror finishes are achievable with the correct fine-grade paste.

Operations finishing plastic parts and 3D-printed components — plastic and resin parts are too soft for ceramic or steel media. Walnut shell’s low hardness and dry process allow surface smoothing and cleaning of plastic parts without the abrasion damage or water absorption that wet processes cause on some polymers.

Finishing delicate or fragile parts — walnut shell is lightweight and low-impact. For parts that cannot tolerate the collision energy of ceramic media in a wet process — thin-walled castings, intricate stampings, filigree jewelry — dry tumbling with walnut shell offers an alternative that reaches all surfaces without part-on-part damage.

Walnut shell vs corn cob media — which to use?

Typical applications

Why Inovatec — a finishing partner, not just a media supplier

Walnut Shell Tumbling Media – FAQs