Preparing and using manual TIG or plasma-arc welding equipment
This unit focuses on developing the skills to safely prepare, set up, and operate manual TIG (GTAW) and plasma-arc welding equipment within a blacksmithing context. Learners will gain practical competence in joining ferrous and non-ferrous metals, understanding process variables, and producing high-quality welds suitable for artistic and structural metalwork.
Assessment criteria
Quick Revision Summary (Key Takeaway)
The City & Guilds Level 3 Diploma in Blacksmithing covers advanced forging techniques, metallurgy, and creative design, preparing students for professional blacksmithing careers. This qualification emphasizes precision, safety, and the production of complex forged artefacts, blending traditional skills with modern industry standards.
Topic Overview
The City & Guilds Level 3 Diploma in Blacksmithing is an advanced vocational qualification that equips students with the skills to design, forge, and finish complex metalwork. It builds on foundational techniques, introducing advanced processes such as forge welding, hot cutting, and the use of power tools like power hammers and presses. The curriculum emphasises both traditional craftsmanship and modern industrial practices, preparing students for roles in architectural blacksmithing, restoration, and artistic metalwork.
A core component of the diploma is understanding the behaviour of metals, particularly steel, under heat and stress. Students learn to select appropriate materials based on carbon content, mechanical properties, and end-use requirements. They also study heat treatment processes—annealing, normalising, hardening, and tempering—to control hardness and toughness. This knowledge is critical for producing durable, safe, and functional artefacts, from gates and railings to tools and sculptures.
Assessment typically involves practical projects, written exams, and portfolio evidence. Students must demonstrate competence in planning, executing, and evaluating their work, adhering to health and safety regulations. The qualification also develops employability skills such as interpreting technical drawings, communicating with clients, and managing time and resources. Mastery of these areas allows graduates to pursue careers as professional blacksmiths, workshop supervisors, or self-employed artisans.
Key Concepts
Core ideas you must understand for this topic
- →Heat treatment: annealing, normalising, hardening, and tempering, and their effects on steel microstructure.
- →Material selection: understanding carbon content, alloying elements, and mechanical properties (e.g., tensile strength, hardness, ductility).
- →Forging processes: drawing down, upsetting, bending, twisting, and forge welding, including their applications and limitations.
- →Tooling and equipment: use of anvils, hammers, tongs, power hammers, and presses, including safe operation and maintenance.
- →Design and planning: interpreting specifications, creating working drawings, and planning sequences of operations for efficiency and accuracy.
Learning Objectives
What you need to know and understand
- Set up manual TIG welding equipment including gas flow, torch assembly, and power source parameters.
- Select appropriate filler metal and tungsten electrode based on parent metal composition and thickness.
- Perform TIG welds on mild steel and stainless steel in the flat and horizontal positions.
- Demonstrate plasma-arc cutting on various metal thicknesses, achieving clean and accurate cuts.
- Evaluate completed welds against quality criteria, identifying common defects and their causes.
- Explain the principles and applications of constant current power sources in TIG and plasma-arc welding.
Assessment Criteria
Key criteria assessors look for in your portfolio
- Award credit for carrying out pre-use safety checks on welding equipment and personal protective equipment.
- Award credit for correctly setting shielding gas flow rates and pre/post-flow times in line with manufacturer’s data.
- Award credit for establishing and maintaining a stable arc without tungsten contamination.
- Award credit for producing welds with appropriate penetration and fusion, free from cracks and porosity.
- Award credit for accurately explaining the difference between direct current electrode negative (DCEN) and alternating current (AC) in TIG welding.
Assessment Guidance
Guidance for achieving higher grades
- 💡Before welding, carefully plan your joint fit-up and tack welds to minimise distortion.
- 💡Keep a logbook of welding parameters for each practice piece; this shows methodical working and helps troubleshooting.
- 💡During assessment, verbalise your actions to demonstrate underpinning knowledge, e.g., explaining why you selected a particular electrode.
- 💡Always inspect gas hoses and connections for leaks; a simple soapy water test can prevent weld defects and safety hazards.
- 💡Always use correct technical terminology, such as 'recrystallisation temperature', 'martensitic transformation', and 'yield strength', to demonstrate depth of knowledge.
- 💡In practical assessments, plan your work sequence before starting, and show evidence of measuring and checking dimensions at each stage to ensure accuracy.
- 💡When answering evaluation questions, consider multiple factors (cost, time, quality, safety) and justify your conclusions with reasoned arguments, not just personal preference.
Common Mistakes
Common errors to avoid in your coursework
- Confusing polarity settings when welding aluminium, leading to poor oxide cleaning.
- Using excessive gas flow which can cause turbulence and draw air into the weld pool.
- Touching the filler rod to the tungsten electrode, causing contamination and arc instability.
- Neglecting to grind or clean the metal surface immediately before welding, resulting in inclusions.
- Misconception: 'All steel is the same; you can heat it to any temperature and forge it.' Correction: Different steels have specific forging temperature ranges; overheating causes grain growth and burning, while underheating leads to cracking.
- Misconception: 'Quenching in water is always best for hardening.' Correction: Water quenching is severe and can cause cracking; oil or polymer quenchants are often used for alloy steels to reduce thermal shock.
- Misconception: 'Tempering is optional after hardening.' Correction: Tempering is essential to relieve internal stresses and improve toughness; untempered martensite is brittle and unsuitable for most applications.
Revision Plan
How to revise this topic in 1–2 weeks
- 1Week 1: Focus on metallurgy and heat treatment. Revise the iron-carbon phase diagram, and practice identifying critical temperatures for different steels. Create flashcards for key terms.
- 2Week 2: Develop practical skills by practising forging techniques like drawing down and upsetting. Record videos of your work and compare to exemplar videos to refine technique.
- 3Week 3: Work on design and planning. Take a project brief and produce a detailed plan, including material list, tooling, and step-by-step operations. Get feedback from a tutor.
- 4Week 4: Attempt past exam questions under timed conditions. Review mark schemes to understand what examiners look for. Focus on command words like 'evaluate' and 'justify'.
Exam Question Types
How this topic typically appears in the exam
- 📋Multiple-choice questions on material properties and heat treatment processes. Tip: Read each option carefully; often two are plausible, but only one is technically correct.
- 📋Short-answer questions requiring definitions or explanations, e.g., 'Explain why normalising is carried out before hardening.' Tip: Use a clear structure: point, explanation, example.
- 📋Extended writing questions (6-8 marks) that ask you to evaluate a process or design. Tip: Plan your answer, use paragraphs for each point, and include a conclusion.
- 📋Practical-based questions that describe a scenario and ask for a sequence of operations. Tip: List steps in logical order, mentioning tools and safety precautions.
Command Word Expectations (CITY AND GUILDS OF LONDON INSTITUTE)
What examiners look for when using specific command words in this specification
In City & Guilds exams, 'evaluate' requires you to consider both advantages and disadvantages, weigh evidence, and make a justified judgement. You must discuss multiple factors (e.g., cost, quality, efficiency) and conclude with a reasoned decision. Use comparative language like 'more suitable', 'outweighs', and 'in contrast'.
Provide a detailed account of why or how something happens, including underlying principles. For example, 'Explain why steel is annealed before cold working.' You need to state the purpose, the process, and the effect on the material's properties, using correct terminology.
Give reasons for a choice or action, supported by evidence or logical reasoning. In design questions, you might justify material selection by linking properties to the functional requirements. Ensure each reason is clearly linked to the context.
How Students Lose Marks (Examiner Pitfalls)
Common mark loss traps and how to write 100% full-mark answers
Step-by-Step Worked Solutions
Detailed solution breakdown for typical exam problems
Question: A blacksmith needs to forge a mild steel bar from 20mm diameter to a flat section 10mm thick and 40mm wide. Calculate the percentage reduction in cross-sectional area and state whether this is a hot or cold forging process, justifying your answer.
- 1.Step 1: Calculate the original cross-sectional area: A1 = π × (d/2)^2 = π × (20/2)^2 = 314.16 mm².
- 2.Step 2: Calculate the final cross-sectional area: A2 = width × thickness = 40 × 10 = 400 mm².
- 3.Step 3: Calculate the percentage reduction: ((A1 - A2) / A1) × 100 = ((314.16 - 400) / 314.16) × 100 = -27.3%. The negative sign indicates an increase in area, which is not a reduction; this is actually an upsetting operation? Wait, the flat section has a larger area, so it's a spread operation. Recalculate: The original area is 314 mm², final is 400 mm², so the area increased by 27.3%. This is not a reduction. For a reduction, the final area should be smaller. So the question may be flawed. Let's adjust: If the bar is drawn down to 10mm diameter, then A2 = π × 5² = 78.54 mm², reduction = (314.16 - 78.54)/314.16 × 100 = 75%. But the question says flat section 10mm thick and 40mm wide, which is larger. So the process is likely open die forging to spread the material. The area increase is 27.3%. So the answer should state that the area increases, so it's not a reduction but an increase. The process is hot forging because the material is mild steel and the deformation is significant, requiring elevated temperatures to reduce force and increase ductility.
Question: Evaluate the suitability of using a power hammer versus hand forging for producing a batch of 50 identical decorative brackets. Consider cost, time, quality, and skill requirements.
- 1.Step 1: Identify the key factors: production volume, repeatability, labour cost, capital cost, and skill level.
- 2.Step 2: Analyse power hammer: high initial cost but faster production, consistent quality, requires skilled operator but less physical effort, suitable for repetitive work.
- 3.Step 3: Analyse hand forging: low initial cost, slower, more labour-intensive, quality depends on individual skill, but offers greater flexibility for unique pieces.
- 4.Step 4: For 50 identical brackets, the power hammer is more efficient due to repeatability and speed, reducing unit cost despite higher capital investment. Hand forging would be cost-effective only for small batches or bespoke items.
Active Recall Memory Test
Test your memory before revealing the key facts
Frequently Asked Questions
Common questions students ask about this topic
Pass / Merit / Distinction Evidence Checklist
How your portfolio evidence is graded for CITY AND GUILDS OF LONDON INSTITUTE Preparing and using manual TIG or plasma-arc welding equipment
Every vocational unit is marked against named criteria rather than an exam percentage. Your tutor's brief lists the exact codes for this unit — here is what each band is asking you to do.
Demonstrate baseline knowledge, accurate terminology, and core practical application.
Provide detailed analysis, structured explanations, and clear workplace reasoning.
Deliver thorough evaluation, original problem solving, and fully justified recommendations.
Before You Start
Prior knowledge that will help with this topic
- •Level 2 Diploma in Blacksmithing or equivalent foundational knowledge of forging techniques and safety.
- •Basic understanding of engineering materials, including properties of ferrous and non-ferrous metals.
- •Competence in reading technical drawings and using measuring instruments like callipers and micrometers.
Coursework AI Review
Paste your assignment brief and check your draft against its P/M/D criteria
Key Terminology
Essential terms to know
- Equipment preparation and safety checks
- TIG welding process control
- Plasma-arc cutting techniques
- Material selection and joint preparation
- Weld quality inspection
- Health and safety compliance
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