# Gauge, Modulus, and Reduction on Bought Sheet

Human page: https://retifist.com/literature-reviews/sheet-gauge-modulus-reduction

## Executive summary

On bought calendered sheet, fit is three knobs. Gauge is roll thickness. Modulus is stiffness at a stated stretch, already set by the mill compound. Reduction is pattern shrink versus body measurements.

Thinner, softer, and smaller-cut are different moves. Use when picking a catalog millimetre, or when two rolls of the same printed thickness feel different.

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## Gauge is catalog thickness

Gauge is thickness (mm or mil). Retail garment-sheet menus commonly about **0.25–1.05 mm**.[^1]

ISO 3302-1 includes calendered rubber sheet in dimensional-tolerance scope. Tolerance framework for solid rubber, not a garment construction chapter.[^2]

Vendor menu language: [Calendered latex sheet](/literature-reviews/sheet-calendered-sheet).

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## Modulus is inherited stiffness

Modulus is stress at fixed extension (MPa at 300%, psi at 500%). Higher modulus is boardier at the same gauge.

The mill already compounded the roll. Same printed thickness can still differ in hand if filler load differs. Inherited filler effects: [Colored sheet: pigment and filler effects](/literature-reviews/sheet-pigment-filler-decks).

At unchanged modulus, a thicker piece of the same rubber is harder to bend and takes more force to reach the same body stretch. Gauge geometry, not a new MPa number.

Elastomeric film must stretch at least **2×** and recover. Fit needs strain margin inside that capability.[^3]

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## Reduction is pattern geometry

Reduction is negative ease: flat pieces drawn smaller than body measurements so the garment must stretch to close.

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## Decision cues

- Catalog millimetre when the wall thickness should change. Read the vendor spec.
- Same-gauge rolls that feel different are different compounds. Bagging after wear often traces to set or aging, not the printed millimetre. [Sheet aging, storage, and care](/literature-reviews/sheet-aging-storage-and-care).
- Change the pattern outline for more or less negative ease.

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## Endnotes

[^1]: Elastomade / WCRP-class retail catalogs — garment-sheet thickness menus about 0.25–1.05 mm.
[^2]: ISO 3302-1 — rubber dimensional tolerances; calendered-sheet scope.
[^3]: Vanderbilt Latex Handbook — elastomeric film stretch-and-recover criterion (≥2×).