Why are products given a surface finish, and which finish suits which material?
Surface treatments and finishes: why materials are finished (protection, appearance, function), and the finishes that suit each material category, including paint and varnish for timber, painting and plating for metals, and self-finishing for polymers.
A focused answer to OCR GCSE Design and Technology J310 on surface treatments and finishes: why materials are finished, and the finishes that suit timber, metals, polymers and textiles.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
What this dot point is asking
OCR J310 expects you to know why products are given a surface treatment or finish and which finish suits which material. The three reasons are protection, appearance and function, and different material categories need different finishes. In the written exam this is tested by giving reasons for finishing and by matching suitable finishes to a product such as outdoor steel.
Why finish a product
A good answer links the finish to the reason: "varnish, to protect the timber from moisture and show the grain" gives both protection and appearance.
Finishes by material
The key knowledge is matching the finish to the material: galvanising and anodising are for metals, varnish and oil are for timber, and polymers are normally self-finishing, so applying a wood finish to plastic or a metal treatment to timber would be wrong.
Some finishes also affect sustainability and safety, which OCR may bring in. Solvent-based paints and varnishes give off fumes and need care and ventilation, while water-based finishes are safer and lower in harmful emissions. A durable finish (powder coating, galvanising) makes a product last longer, which reduces waste over its life, an example of the "reduce" principle. A finish can also make a surface food-safe or easy to clean, which is a functional as well as a protective reason. A strong answer therefore links the finish not only to protection and appearance but, where relevant, to safety, hygiene and the product's life span.
Try this
Q1. Give two reasons a product is given a surface finish. [2 marks]
- Cue. Any two of protection, appearance, function.
Q2. Name a suitable finish to protect outdoor mild steel from rust. [1 mark]
- Cue. Paint over a primer, powder coating, or galvanising.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR J310/01 20193 marksGive three reasons why a product might be given a surface finish.Show worked answer →
A 3-mark question, one mark per distinct reason.
Protection: a finish protects the material from damage such as moisture, rust, wear or rot (varnish on timber, paint or plating on steel). Appearance: a finish improves the look, adding colour, gloss or texture to suit the market. Function: a finish can change how the surface behaves, for example making it easier to clean, waterproof, non-slip or food-safe.
Markers reward three different reasons (protection, appearance, function). Repeating one idea in different words caps the mark.
OCR J310/01 20214 marksA mild steel garden bench will be used outdoors. Explain two suitable finishes that would protect it and improve its appearance.Show worked answer →
A 4-mark Explain wants two finishes suited to outdoor steel.
Finish 1, painting (after a primer). A primer plus a coat of exterior paint seals the steel from moisture and air, preventing rust, and adds colour to suit a garden, though it needs reapplying as it weathers.
Finish 2, powder coating (or galvanising). Powder coating bakes a tough, even polymer layer onto the steel that resists rust and scratches and gives a durable coloured finish; galvanising coats the steel in zinc to stop it rusting. These are more durable than ordinary paint.
Markers reward two suitable finishes, each explained with protection (stops rust) and appearance, applied to outdoor steel. Naming a finish unsuitable for metal (such as wood varnish) loses the mark.
Related dot points
- Wastage and addition processes: shaping by removing material (sawing, drilling, turning, milling, laser cutting) and by joining material together (adhesives, mechanical fixings, welding, soldering), and choosing the right process for a material.
A focused answer to OCR GCSE Design and Technology J310 on wastage and addition processes: shaping by removing material and by joining material together, and matching the process to the material.
- Quality control and accuracy: tolerances and how to read them, quality control checks during production, and using jigs, templates, patterns and CAM to ensure accuracy and consistency in batch and mass production.
A focused answer to OCR GCSE Design and Technology J310 on quality control and accuracy: tolerances and how to read them, quality checks, and using jigs, templates and CAM for consistency.
- Metals: ferrous metals, non-ferrous metals and alloys, the difference between them, their physical and working properties, common examples, and typical uses.
A focused answer to OCR GCSE Design and Technology J310 on metals: ferrous metals, non-ferrous metals and alloys, the difference between them, their properties, common examples and typical uses.
- Timbers: natural hardwoods and softwoods and manufactured (manmade) boards, their physical and working properties, the difference between hardwood and softwood, common examples, and typical uses.
A focused answer to OCR GCSE Design and Technology J310 on timbers: natural hardwoods and softwoods and manufactured boards, their properties, the hardwood and softwood difference, examples and uses.
- Polymers: thermoforming (thermoplastic) and thermosetting polymers, the difference between them, their physical and working properties, common examples, and typical uses.
A focused answer to OCR GCSE Design and Technology J310 on polymers: thermoforming and thermosetting plastics, the difference between them, their properties, common examples and typical uses.
Sources & how we know this
- OCR GCSE (9-1) Design and Technology (J310) specification — OCR (2017)