---
title: "What is a Cardboard made of?"
description: "Two flat kraft paper liners glued either side of a fluted paper medium — the flutes do all the work. Every component, the material it uses, and the constraint that m"
url: https://atoneplace.net/made-of/cardboard/
site: "At One Place"
---

# What is a Cardboard made of?

**What is a Cardboard made of?: Two flat kraft paper liners glued either side of a fluted paper medium — the flutes do all the work.**

Corrugated board is stiff in one direction only, which is why a box is strong stacked upright and weak on its side: compression strength runs along the flutes. Flute size is a trade-off with its own alphabet — A and C flutes are tall and cushion well, B is short and prints well, E and F are thin enough to replace folding cartons. The corrugation idea arrived from an unlikely place: fluted paper was patented in 1856 as a liner for tall hats, and only in 1871 did anyone use it as packaging. Cardboard is one of the most recycled materials in the world, though each pass shortens the fibres, so recycled board always needs some fresh pulp blended in.

## Component by component

*Every material is a choice, and the third column is the constraint that drove it.*

| Part | Material | Why that material |
| --- | --- | --- |
| liners | kraft paper, often with a proportion of recycled fibre | Kraft pulping leaves long, strong fibres because it does not degrade the cellulose the way older processes did. |
| fluting medium | semi-chemical or recycled paper, steam-softened and pressed into arches | The arches turn a floppy sheet into a stiff panel by holding the two liners apart, the same trick as an I-beam. |
| adhesive | starch glue, usually from maize | Starch is cheap, sets on hot rollers in seconds and does not interfere with recycling the fibre afterwards. |
| water resistance (where present) | wax or polymer coating | Corrugated board loses most of its strength when damp, so refrigerated and produce boxes are treated — and the coating is what makes them hard to recycle. |

## Other stationery and paper objects

- [Pencil](https://atoneplace.net/made-of/pencil/) — Graphite mixed with clay and fired, glued inside two grooved halves of softwood. No lead, ever.
- [Paper](https://atoneplace.net/made-of/paper/) — Cellulose fibres from wood pulp, plus up to a third mineral filler, sizing and brightener.
- [Ballpoint pen](https://atoneplace.net/made-of/ballpoint-pen/) — A tungsten carbide ball a millimetre across, rolling in a brass socket, fed by thick oil-based ink.
- [Glitter](https://atoneplace.net/made-of/glitter/) — Aluminium-coated polyester film, colour-coated and chopped into fragments — by definition a microplastic.
- [Crayon](https://atoneplace.net/made-of/crayon/) — Paraffin wax with pigment stirred in, poured hot into a mould and cooled. Almost nothing else.
- [Eraser](https://atoneplace.net/made-of/eraser/) — Either natural rubber with fine abrasive and oil, or plasticised PVC — two different ways of lifting graphite.
- [Blackboard chalk](https://atoneplace.net/made-of/chalk/) — Mostly calcium sulfate — plaster of Paris — rather than the calcium carbonate the name suggests.
- [Playing card](https://atoneplace.net/made-of/playing-card/) — Two sheets of paper laminated around a black glue core, then coated in plastic — or solid PVC.
- [Postage stamp](https://atoneplace.net/made-of/postage-stamp/) — Coated paper with phosphor bands, printed in security inks, on either water-activated gum or a self-adhesive.

## Common questions

### What is a Cardboard made of?

Two flat kraft paper liners glued either side of a fluted paper medium — the flutes do all the work.

### What is the liners of a Cardboard made of?

Kraft paper, often with a proportion of recycled fibre. Kraft pulping leaves long, strong fibres because it does not degrade the cellulose the way older processes did.

### What is the fluting medium of a Cardboard made of?

Semi-chemical or recycled paper, steam-softened and pressed into arches. The arches turn a floppy sheet into a stiff panel by holding the two liners apart, the same trick as an I-beam.

## Related pages

- [Pencil](https://atoneplace.net/made-of/pencil/)
- [Paper](https://atoneplace.net/made-of/paper/)
- [Ballpoint pen](https://atoneplace.net/made-of/ballpoint-pen/)
- [Glitter](https://atoneplace.net/made-of/glitter/)
- [Crayon](https://atoneplace.net/made-of/crayon/)
- [Eraser](https://atoneplace.net/made-of/eraser/)
- [Blackboard chalk](https://atoneplace.net/made-of/chalk/)
- [Playing card](https://atoneplace.net/made-of/playing-card/)
- [Tennis ball](https://atoneplace.net/made-of/tennis-ball/)
- [Banknote](https://atoneplace.net/made-of/banknote/)
- [Golf ball](https://atoneplace.net/made-of/golf-ball/)
- [Glass](https://atoneplace.net/made-of/glass/)
- [Soccer ball](https://atoneplace.net/made-of/soccer-ball/)
- [Marshmallow](https://atoneplace.net/made-of/marshmallow/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)