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How do designers select materials from standard stock forms and calculate the cost of the material used?

Selecting materials and stock forms, and costing: choosing a material to suit a product, the standard stock forms materials are supplied in (sheet, bar, rod, tube, section), and calculating material cost from price per unit, including allowing for waste.

A focused answer to Eduqas GCSE Design and Technology (C600) on selecting materials and stock forms and costing: standard stock forms, how to choose a material, and a worked material-cost calculation including waste.

Generated by Claude Opus 4.810 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. Selecting a material
  3. Standard stock forms
  4. Costing materials
  5. Try this

What this dot point is asking

Eduqas C600 expects you to select materials to suit a product, know the standard stock forms materials come in, and cost the material used, one of the set C600 maths skills. In the written exam this is tested by Explain questions justifying a material choice and by applied costing calculations from a price per sheet, length or kilogram, including allowing for waste.

Selecting a material

A good selection weighs the working properties (strength, hardness, toughness), physical properties (weight, conductivity), appearance, cost, ease of manufacture and environmental impact against what the product needs, then justifies the choice with a property. There is rarely one right answer; the skill is the reasoned trade-off.

The trade-off is the point Eduqas rewards. A premium material may perform best but cost too much for a mass-market product; a cheaper material may save money but compromise durability or appearance. The scale of production matters too: a one-off can use an expensive material, while a mass-produced product must keep the unit material cost low. A strong answer names the property that decides the choice (for example "aluminium for its low density") and acknowledges what is traded away (for example higher cost than steel).

Standard stock forms

Buying in standard forms is cheaper than custom shapes, but the chosen form affects waste. Choosing a stock form close to the finished size cuts the offcut: a bracket cut from angle section wastes less than the same bracket cut from solid bar, and parts nested tightly on a sheet leave fewer gaps. Stock forms also come in standard sizes (a sheet of MDF is commonly 1220 mm by 2440 mm, metal bar in set diameters), so a designer works to those sizes to avoid paying for material that is thrown away.

Costing materials

Costing is a set maths skill. The method is: find the quantity of stock used, add a waste allowance, then multiply by the price per unit.

Try this

Q1. A 2 m length of timber costs 10 pounds. Calculate the price per metre. [1 mark]

  • Cue. 10÷2=510 \div 2 = 5 pounds per metre.

Q2. A product uses 0.5 m of bar at 6 pounds per metre, with 10 percent added for waste. Calculate the material cost. [2 marks]

  • Cue. 0.5×1.1=0.550.5 \times 1.1 = 0.55 m, ×6=3.30\times 6 = 3.30 pounds.

Exam-style practice questions

Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Eduqas C600 20194 marksA workshop buys steel bar at 12 pounds per metre. A product needs 0.4 m per item, and 10 percent extra is allowed for waste. Calculate the material cost for one item.
Show worked answer →

A 4-mark calculation: marks for adding the waste allowance, the length, the method and the final cost with a unit.

First add the waste allowance to the length: 10 percent of 0.4 m is 0.04 m, so the length needed including waste is 0.4 plus 0.04 equals 0.44 m.

Then multiply by the price per metre: 0.44 times 12 equals 5.28 pounds.

So the material cost for one item is 5 pounds 28 pence. Markers reward the waste step (0.44 m), the multiplication (0.44 times 12) and the answer with a unit. Forgetting the waste allowance, or dropping the unit, loses marks.

Eduqas C600 20223 marksA sheet of MDF measuring 1200 mm by 600 mm costs 9 pounds. A shelf uses a piece 600 mm by 300 mm. Calculate the cost of the material in the shelf.
Show worked answer →

A 3-mark calculation: marks for the two areas, the fraction of the sheet, and the cost.

The sheet area is 1200 times 600 equals 720000 mm squared. The shelf area is 600 times 300 equals 180000 mm squared.

The shelf uses 180000 divided by 720000 equals 0.25, a quarter of the sheet.

A quarter of 9 pounds is 9 times 0.25 equals 2.25 pounds, so the material in the shelf costs 2 pounds 25 pence. Markers reward the areas, the fraction (one quarter) and the cost. This ignores offcuts; in practice waste raises the real cost per shelf.

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