How do you classify papers, boards and timbers, and how do their properties decide where each is used?
Classification, common types, properties and working characteristics of papers and boards (cartridge, bleed-proof, layout, tracing, grammage by weight) and of timbers (hardwoods, softwoods, manufactured boards such as MDF, plywood and chipboard), including conversion, seasoning, stock forms and the reasons each is selected for a product.
A focused answer to the Edexcel 9DT0 content on papers and boards and on natural and manufactured timbers, covering classification, grammage, common types, seasoning, stock forms and the working properties that decide which is selected for a product.
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What this dot point is asking
Edexcel wants you to classify papers and boards and natural and manufactured timbers, know the common types and their stock forms, and explain the working properties (and processing such as seasoning and conversion) that decide why a particular paper, board or timber is selected for a given product.
The answer
Classifying papers and boards by grammage
Common types and where each is used:
- Cartridge paper (about to gsm): a slightly textured general drawing paper for sketching, pencil and light paint.
- Bleed-proof paper: coated so spirit-marker ink does not spread, giving crisp presentation renderings.
- Layout paper (about gsm): thin and translucent for tracing and developing ideas quickly.
- Tracing paper: transparent, for copying and overlaying drawings.
- Corrugated card: a fluted core between two liners, giving low weight with stiffness and impact protection for packaging.
- Foam board: a foam core between paper faces, light and rigid for models and mounting.
- Solid white board and duplex board: smooth printable boards for packaging and point-of-sale.
Classifying timber: hardwoods, softwoods and manufactured boards
Manufactured boards are engineered from timber by-products and so avoid the size limits, defects and grain direction of natural boards:
- MDF (medium density fibreboard): fine wood fibres bonded with resin, giving a dense, uniform board with no grain, smooth faces and easy machining; it takes paint and veneer well but is heavy and the dust needs extraction.
- Plywood: thin veneers glued with grain at right angles in each layer (cross-banding), giving high strength in two directions and resistance to splitting; marine grade uses waterproof adhesive.
- Chipboard: wood chips bonded with resin, cheap and used as a core (often melamine-faced) for kitchen worktops and budget furniture, but weak in tension and poor with moisture.
Conversion, seasoning and stock forms
A felled log is converted into usable boards by sawing. Through-and-through (slab) sawing is quick and economical but boards can warp; quarter sawing is more wasteful but gives stable, attractive boards that resist cupping.
Seasoning (air drying or kiln drying) lowers the moisture content so the timber is more stable, stronger, less likely to rot and ready to finish. Natural timber is sold in standard stock forms: planks, boards, strip, dowel and mouldings in nominal sizes; manufactured boards come as large flat sheets (for example mm). Designing to standard stock sizes reduces waste and cost.
Examples in context
Packaging designers pick corrugated card for transit boxes because its fluted core gives stiffness and crush resistance for very little weight, while solid white board is chosen for printed retail cartons. Furniture makers veneer MDF for cabinets that need a flawless painted or wood-effect finish, use plywood where two-directional strength matters (drawer bases, curved formed seats), and reserve solid oak or ash for high-value items where the grain is a selling point. Model makers reach for foam board and cartridge paper for quick concept models and bleed-proof paper for the final marker-rendered presentation boards.
Try this
Q1. State what grammage measures and give its unit. [1 mark]
- Cue. The mass per unit area of paper or board, measured in grams per square metre (gsm).
Q2. Give one reason a designer would choose plywood rather than chipboard for a curved seat. [2 marks]
- Cue. Plywood's cross-banded veneers give high strength in two directions and bend without splitting, whereas chipboard is weak in tension and would crack when formed.
Q3. Explain why timber is seasoned before use. [2 marks]
- Cue. Seasoning lowers the moisture content, making the timber more dimensionally stable, stronger and less prone to warping, rot and movement once in the product.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20194 marksExplain two reasons why medium density fibreboard (MDF) is often chosen instead of natural timber for flat-pack furniture panels.Show worked answer →
Award one mark for each reason identified and one for the justification (two linked marks each).
Reason one: MDF has no grain direction, so it has consistent properties in all directions and will not split along a grain when screwed near an edge. This makes it dimensionally stable and predictable for machine cutting in batch production.
Reason two: MDF has a smooth, dense, uniform surface that takes paint, veneer or a foil wrap directly without filling, lowering finishing cost. It is also available in large, flat, low-cost sheets, which suits the rectangular panels of flat-pack furniture and reduces waste.
Markers reward two distinct reasons each developed with a consequence for the product, not just a list of properties.
Edexcel 20216 marksA designer is selecting a board for a high-quality presentation model that must show clean marker-pen rendering. Evaluate the suitability of bleed-proof paper compared with cartridge paper for this purpose.Show worked answer →
This is an extended-response item marked on a levels basis (use of correct properties, comparison and a justified judgement).
Bleed-proof paper has a coated, sized surface that stops marker-pen ink spreading into the fibres, so colours stay crisp with sharp edges, which is exactly what a presentation rendering needs. Cartridge paper (typically about 120 to 150 gsm) is heavier and good for sketching and light shading, but its more absorbent surface lets spirit-based marker ink bleed and feather, blurring edges.
A strong answer judges that bleed-proof paper is more suitable for the marker rendering because the surface quality controls ink spread, while noting that cartridge paper may still be chosen if the model also needs to take pencil, paint or be handled, since cartridge is more robust. The judgement should be justified against the stated need (clean marker rendering), not left open.
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Sources & how we know this
- Pearson Edexcel A-Level Design and Technology: Product Design (9DT0) specification — Pearson Edexcel (2017)