# Walnut shell media

Granular walnut-shell blast media, with exact supplier grades, composition, sieve limits, density and moisture bases, and limits of cleaning and reuse claims.

Reviewed: 2026-10-29

Tags: abrasives, blasting, organic-media

## Identity and formulation

Walnut shell blast media is crushed and graded shell material. Airblast describes its product as crushed, cleaned, and sifted walnut shells. Guyson describes an entirely ground or crushed shell product. These descriptions concern the shell, rather than whole nuts, edible kernels, or kernel flour. Neither sheet names a botanical species. [Airblast technical sheet][airblast], [Guyson data sheet][guyson]

Composition Materials' Walnut Shell Grit & Flour SDS identifies English walnut shell, *Juglans regia*, among its synonyms. Section 3 declares Natural Walnut Shell, CAS 84012-43-1, at 100 weight-%. This is a whole-material declaration, not a cellulose, lignin, protein, or contaminant assay. It does not certify absence of additives or cross-contamination. The same SDS explicitly identifies possible walnut proteins and allergic reactions. Its industrial-use description does not establish food grade or absence of allergens. [Composition Materials SDS, sections 1–4][sds]

SWARCOBLAST Walnussschalengranulat is a distinct formulation. Its April 2025 technical information says it is partly combined with stone-fruit pits, without preservatives or iron content. The sheet does not identify the fruit species, blend proportions, or a detection limit for iron. An all-walnut formulation cannot be inferred from this product name. [SWARCO technical information, p. 1][swarco]

Shell grit also differs from [corn cob finishing media](corn-cob-finishing-media.md), [plastic blasting media](plastic-blasting-media.md), and mineral abrasives. Kramer separately describes treated tumbling media made with walnut shell, corn cob, or other bases plus abrasives, lubricants, binders, and polishing agents. Dry tumbling means no added process water; it does not mean an untreated carrier. The family description does not disclose every named grade's complete formulation. [Kramer Premium Treated Media][treated]

## Supplier property comparisons

These entries retain the suppliers' property names. The sheets generally describe product families or typical values, rather than grade-specific lot acceptance results.

| Product and source | Shape and hardness | Density entries as supplied | Moisture and ash |
| --- | --- | --- | --- |
| Composition Materials Ground Walnut Shell Grit Products | Brown, granular; Mohs 3.5; Rockwell 91; Brinell 190 | Specific gravity 1.2–1.4; dry packing density 22–53 lb/ft³ | Free moisture 3–11%, 80 °C for 15 hours; ash 1.5% |
| Guyson Walnut Shell | Angular; light brown; Mohs 3.00–3.50 | Bulk density 0.44–0.77 kg/L | Water content 10–15%; ash unreported |
| Airblast Walnut Shell Blasting Media | Angular; Mohs 3.00–3.50 | Bulk Weight 0.73 g/cm³; Specific Weight 1.12 g/cm³ | Moisture and ash unreported |
| SWARCOBLAST Walnussschalengranulat | Shape unreported; approximately Mohs 2.5–3.5 and Vickers 25–30 | Specific weight approximately 1.0–1.2 g/cm³; bulk weight approximately 0.7 kg/L | Moisture approximately 14.0%; water solubility approximately 8.5%; mineral matter approximately 1.0%, not labeled ash |

Sources for the respective rows are the [Composition Materials TDS][tds], [Guyson sheet][guyson], [Airblast sheet, p. 2][airblast], and [SWARCO sheet, p. 1][swarco]. Rockwell scale, Brinell and Vickers test conditions, density methods, moisture denominators, and ash test conditions are not supplied. The Composition Materials moisture entry supplies temperature and duration, but not a named test standard or wet-mass versus dry-mass denominator. Its SDS instead gives specific gravity 1.2–1.35 relative to water and pH 4–5, while its TDS gives 1.2–1.4 and pH 4–6 in neutral water at 25 °C. These are unresolved source differences, not a combined tolerance. [TDS][tds], [SDS, section 9][sds]

The TDS analyses describe lignocellulosic material, but do not establish identical chemistry across suppliers.

| Reported analysis | Composition Materials | SWARCOBLAST |
| --- | --- | --- |
| Cellulose | 40–60% | Approximately 45.7% |
| Lignin | 20–30% | Not separately stated |
| Hemicellulose | Not stated | Approximately 23.3% |
| Wood fibers | Not separately stated | Approximately 19.5% |
| Other listed entries | Nitrogen 0.10%; chlorine 0.10%; cutin 1.0%; toluene solubility 0.5–1.0% | Fat approximately 0.2%; mineral matter approximately 1.0% |

The [Composition Materials TDS][tds] repeats its nitrogen entry; that repetition is not a second constituent. The [SWARCO sheet][swarco] does not call its wood-fiber entry lignin. Neither table states analytical methods, dry or as-received basis, or a complete mutually exclusive mass balance. Solvent solubility is a test property, not an additional ingredient percentage to add to polymer fractions.

## Grades and sieve evidence

Composition Materials labels its sieve table as percentages through the screen. The selected rows below retain every nonblank limit for each selected product. They are cumulative passing limits, rather than percentages retained. The sheet does not specify mass versus count basis or a sieve-test standard. [Composition Materials sieve specifications][tds]

| Exact product | U.S. screen label | All stated passing limits |
| --- | --- | --- |
| AD-3B | 12/20 | No. 8 ≥100%; No. 12 ≥95%; No. 20 ≤5%; No. 35 ≤1% |
| AD-7B | 35/60 | No. 12 ≥100%; No. 20 ≥99%; No. 35 ≥88%; No. 60 ≤14%; No. 100 ≤1% |
| AD-9B | 40/100 | No. 30 ≥99.9%; No. 40 ≥90%; No. 100 ≤10%; No. 200 ≤2% |
| WF-2 | -100 | No. 50 ≥100%; No. 100 ≥88% |

The WF family is identified as flour in the SDS synonyms. It is ground shell flour, distinct from edible kernel flour. Kramer also calls 40/100, 60/100, 60/200, -100, -200, and -325 products flour grades. Its nominal 12/20 range is 1.70–0.85 mm and 35/60 is 0.50–0.25 mm. Its images are labeled for comparison only. [Composition Materials SDS, section 1][sds], [Kramer grade table and image note][kramer]

Other product labels have different meanings. Guyson lists 8/16, 16/30, 25/52, 40/100, and 60/120 without a distribution or sieve standard. [Guyson sheet][guyson] Airblast offers seven nominal ranges spanning 0.20–0.45 through 1.70–2.40 mm, without passing percentages. [Airblast sheet][airblast] SWARCO's Type 6/12 means 100–450 µm and Type 12/3 means 1000–1700 µm. These are manufacturer type codes, not U.S. mesh pairs. The full SWARCO program spans 100–250 to 6000–10000 µm. [SWARCO size table][swarco]

**Synthesis.** A nominal sieve pair is not a complete distribution, maximum dimension, or median diameter D50. Passing depends on particle geometry and the sieve procedure. The selected passing limits constrain a distribution without reporting every particle size. They do not prove clearance through a workpiece opening or complete recovery from a recess.

## Quantity bases and conditional interpretation

The following are definitions and synthesis, not additional supplier measurements.

| Quantity | Meaning and limit |
| --- | --- |
| Bulk or packing density | Sample mass divided by occupied bulk volume, including spaces between granules. Packing, size distribution, and moisture affect the result. |
| Material, particle, or apparent density | Requires the method's definition of particle volume and treatment of pores. An unspecified specific-weight entry cannot establish true solid density or apparent density. |
| Specific gravity | Dimensionless ratio to a stated reference density. A supplier entry printed in g/cm³ retains a density unit, even if named specific weight. |
| Moisture percentage | Wet basis divides water mass by moist sample mass. Dry basis divides water mass by dry solids mass. The denominator cannot be supplied by assumption. |
| Absorbency | Requires the liquid, initial condition, contact time, drainage conditions, and uptake denominator. Liquid mass per initial media mass differs from liquid volume per bulk media volume. |

A unit conversion gives 0.73 g/cm³ = 0.73 kg/L = 730 kg/m³ for Airblast's bulk-weight entry. It does not convert that value into its separately reported specific weight. None of the four technical sheets reports a conditioned liquid-uptake test. Their moisture or water-solubility values therefore provide no absorption capacity, drying rate, or oil-removal efficiency. [Airblast][airblast], [Composition Materials][tds], [Guyson][guyson], [SWARCO][swarco]

**Synthesis.** Mohs hardness describes scratch resistance, not impact fracture, particle survival, cleaning rate, or workpiece finish. Angular describes shape without quantifying edge sharpness. Neither property supplies a reuse-cycle count or proves zero workpiece removal.

## Application and used-media limits

Airblast lists cleaning soft metals, fiberglass, stone, and wood. Guyson lists corrosion and carbon removal, deflashing, deburring, and paint removal. These are application descriptions without matched test results for alloy, coating, roughness, dimensional loss, or contamination. Guyson's wording limits damage to a low likelihood; it is not a guarantee of no damage. [Airblast][airblast], [Guyson][guyson]

Kramer makes reuse conditional on clean media, suitable particle integrity, and application conditions. Its broader preservation claims do not supply a universal finish or lifetime. [Kramer reuse discussion][kramer] SWARCO's page 2 expressly says the information does not warrant properties and that suitability remains application dependent. [SWARCO qualification notes][swarco]

**Synthesis.** Cleaning, coating removal, deburring, matting, and polishing are distinct outcomes. A visually clean part does not prove absence of retained shell, embedment, organic residue, corrosive contamination, or compatibility with subsequent coating. Recovered media can contain removed coatings, workpiece material, oil, and fines. No source inspected here establishes a universal no-scratch result, corrosion outcome, qualified aircraft process, or customer capability.

Guyson calls its product biodegradable, while Composition Materials markets its shell products as biodegradable and sustainable. These remain supplier claims without a stated degradation test or time. The Composition Materials SDS leaves persistence and degradability undetermined. A renewable or recycled-feedstock description does not measure environmental impact, prove harmless dust, or qualify spent-media disposal. [Guyson][guyson], [Composition Materials product page][products], [SDS, sections 12–13][sds]

The SDS classifies the supplied material as combustible dust and describes an explosive dust-air mixture under appropriate conditions. This and its allergen statement preclude interpreting plant origin as universal absence of exposure hazards. Its disclaimer also limits the document to the designated material, rather than all mixtures or processes. Guyson's disposal paragraph separately recognizes application contamination. Neither sheet establishes the classification of a particular spent-media stream. [Composition Materials SDS, sections 2, 5, 13, and 16][sds], [Guyson disposal note][guyson]

## Source versions and coverage

Reviewed 29 October 2026 PDT. The Composition Materials TDS is an undated one-page family sheet. Its complete property, analysis, and sieve tables were inspected. Guyson's one-page sheet is marked January 2020. Airblast's two-page sheet is marked 2024-01-ENG. SWARCO's two-page German sheet is revised 9 April 2025; its tables and qualification notes govern the translated descriptions here. The older English 12/2020 PDF could not be retrieved and is not treated as current evidence.

The Composition Materials SDS is version 5, revised 12 December 2023, seven pages. Kramer pages and the Composition Materials product page are retrieval snapshots. Their displayed page dates and URL upload directories do not establish a revision date for every current statement.

Coverage includes selected exact grades and full available technical-sheet context, not delivered-lot certification. Complete additive and residual-protein assays, conditioned absorption methods, quantified fracture life, dust explosibility tests, finish trials, downstream cleanliness limits, and customer acceptance remain unverified. This reference provides no operating, cleaning, or waste-treatment recipe.

[tds]: https://compomat.com/wp-content/uploads/2017/05/Walnut-Shell-TDS-Spec-Sheet.pdf
[sds]: https://compomat.com/wp-content/uploads/2024/02/Walnut_Shell_SDS.pdf
[guyson]: https://s3-eu-west-1.amazonaws.com/resources.guyson.co.uk/product-downloads/Walnut.pdf?mtime=20240917152714
[airblast]: https://airblast.com/wp-content/uploads/2024/11/Walnut-blasting-media.pdf
[swarco]: https://www.swarco-indusferica.com/wp2024/wp-content/uploads/2025/04/ti_swarcoblast_walnussschalengranulat_neu.pdf
[treated]: https://kramerindustriesonline.com/product/premium-treated-vibratory-tumbling-media/
[kramer]: https://kramerindustriesonline.com/product/walnut-shell-blasting-media-grit/
[products]: https://compomat.com/ground-walnut-shell-products/