Lesson 1Safe Pressure Ranges and Regulator Settings for Typical Mild Steel Plate CutsSummarises safe oxygen and fuel pressure ranges for mild steel plate, proper regulator adjustments, and gauge readings. Stresses avoiding overpressure, backfires, and poor cut quality through stable, balanced settings in local boilermaking practices.
Typical pressures by plate thicknessSetting and balancing regulatorsReading and interpreting gaugesAdjusting for preheat and piercingRecognizing unsafe pressure signsLesson 2Metallurgy Basics of Carbon/Mild Steel for Oxy-Fuel Cutting (Thickness, Oxidation, Heat-Affected Zone)Introduces basic metallurgy of carbon and mild steel relevant to oxy-fuel cutting. Explains oxidation, heat-affected zone behaviour, thickness effects, and how composition and microstructure affect cut quality and distortion in Namibian steel fabrication.
Carbon content and steel categoriesRole of iron oxidation in cuttingHeat-affected zone and hardnessThickness, mass, and heat flowEffects on distortion and warpingRecognizing metallurgical defectsLesson 3Cutting Technique for Straight, Square Cuts (Torch Angle, Travel Speed, Preheat/Run-On, Piercing)Explains torch handling for straight, square cuts, including correct torch angle, stand-off, and travel speed. Details preheat timing, run-on and run-off tabs, piercing technique, and maintaining a steady kerf line for accurate work.
Torch angle and nozzle stand-offPreheat time and puddle formationPiercing procedures and safetyControlling travel speed and kerfUsing run-on and run-off tabsMaintaining a steady hand motionLesson 4Edge Cleaning and Preparation After Cutting (Grinding, Slag Removal, Dimensional Checks)Details post-cut edge cleaning using chipping, grinding, and filing. Explains slag and dross removal, deburring, and dimensional checks with gauges and squares to prepare edges for welding, fitting, or further machining in boilermaking tasks.
Removing slag and dross safelyGrinding and blending cut edgesDeburring holes and cornersChecking squareness and bevelMeasuring length and straightnessPreparing edges for weldingLesson 5Marking, Layout, and Measurement Techniques for Cutting Rectangular Frame Parts (Scribing, Square, Templates)Covers accurate layout for rectangular frame parts using squares, scribes, and templates. Explains datum selection, transfer of dimensions from drawings, and marking methods that remain visible but minimise surface damage during fabrication.
Reading drawings and dimensionsChoosing datums and reference edgesUsing squares, tapes, and rulesScribing and center punching linesUsing templates and jigsChecking diagonals and squarenessLesson 6Pre-Use Inspection and Leak Testing Procedures (Visual Inspection, Soap Test, Flashback Device Checks)Outlines pre-use inspection steps for cylinders, hoses, regulators, and torch. Explains soap solution leak testing, checking flashback devices, and verifying valves and connections to prevent gas leaks, flashbacks, and equipment failure safely.
Visual checks of hoses and jointsInspecting regulators and gaugesSoap solution leak test methodTesting flashback arrestorsVerifying valve operationDocumenting and tagging defectsLesson 7Oxy-Fuel System Components and Maintenance (Cylinders, Regulators, Hoses, Torch, Tips, Flashback Arrestors)Describes oxy-fuel system components and their functions, including cylinders, regulators, hoses, torch body, tips, and flashback arrestors. Covers basic maintenance, cleaning, and replacement intervals to ensure safe, reliable service in workshops.
Cylinder valves and fittingsRegulators and pressure controlHose types, color codes, and careTorch body, mixers, and valvesTip types, cleaning, and wearFlashback arrestors and check valvesLesson 8Common Practical Troubleshooting and Quality Checks (Undercut, Taper, Dross)Focuses on recognising and correcting common cut defects such as undercut, taper, drag lines, and dross. Provides practical adjustments to speed, tip size, and pressures, plus simple quality checks for production work in Namibian settings.
Identifying undercut and washoutRecognizing taper and bevel errorsHeavy dross and drag line causesAdjusting speed, height, and angleCorrecting pressure and tip issuesSimple visual and gauge checksLesson 9Handling, Storage, and Identification of Cut Parts (Tagging, Stacking, Corrosion Prevention)Explains safe handling and storage of freshly cut parts, including identification, tagging, and orientation marks. Covers stacking methods, dunnage use, and basic corrosion prevention to protect dimensional accuracy and traceability in storage.
Tagging and part identificationMarking orientation and fit-up sidesSafe lifting and manual handlingStacking, dunnage, and supportsShort-term corrosion protectionShop storage records and labelingLesson 10Gas Selection and Tip Sizing for Common Plate Thicknesses (Acetylene vs Propane, Recommended Tip Numbers)Covers selection of oxygen-fuel gas combinations and tip sizes for common mild steel thicknesses. Compares acetylene and propane performance, and lists typical tip numbers and flow rates for efficient, economical cutting in local operations.
Comparing acetylene and propaneGas choice by thickness and dutyManufacturer tip charts and dataSelecting tip size and orificeFlow rates and preheat adjustmentEffects on cut speed and quality
