Welding for Vehicle Restorers

Bruce Macleod

• Publisher: Crowood
• Year: 2020
• Print ISBN: 9781785006814
• eBook ISBN: 9781785006821
• Topic: Technology & Engineering
• Subtopic: Mechanical Engineering
• Index: Technology & Engineering

The techniques used in the welding of thin sheet metal as used on vehicle bodies are vastly different to those used in welding heavier structures. This book covers the various methods of welding used to make and repair sheet metal body panels. Whereas some forms of welding are straightforward, others require a significant amount of skill. The important thing for anyone wanting to achieve a good finish to body repair work is to start with the correct techniques: skill then comes with practice. When restoring a classic car of some value, it is worth putting the time and effort into becoming skilled in the use of all the techniques covered in this book in order to achieve a professional finish to your work. With nearly 200 colour photographs and illustrations, this book lists the equipment and materials required to achieve a successful outcome. It describes the different methods of welding and how to choose the correct method for the job and provides step-by-step practical guidance to achieve a professional result. Finally, it focuses on the welding of mild steel and aluminium alloy, with some reference to the welding of brass and stainless steel sheet metal.

CHAPTER ONE

HEALTH AND SAFETY

Health and safety should always be taken seriously, as severe injury and long-term health conditions can result from a lack of awareness and discipline in using protective measures. To reduce the risk of harm to yourself and others, it is always necessary to understand the risks and to use the appropriate protective equipment. It is important to develop safe working habits, as a momentary lapse in concentration when working on vehicles can cause serious injury. Tiredness plays a part in many accidents, so avoid carrying out any operations using power tools or other dangerous equipment when feeling fatigued. Working alone increases the risk of harm, as you are more likely to lift something that is too heavy for one person. You may also be unaware of other incidents in the workshop, such as a fire starting, if you are concentrating on a particular job. The environment you are working in can create risks, as many household garages have poor floor surfaces, leaky roofs and outdated electrics, all of which increase the chances of an accident occurring.

Always perform a quick visual risk assessment before carrying out any work on a vehicle so as to reduce the risk of injury or harm. The appropriate PPE (Personal Protective Equipment) should be used in order to reduce the risk of harm, as there are serious health issues that can arise from welding on vehicle bodies caused by:

•fumes

•heat

•electric shocks

•intense light created by the welding process

•sharp edges to metal panels

•trip and slip hazards

•movement of heavy objects.

Grinding metal is also a common cause of injuries arising from:

•sparks

•dust

•projectiles

•noise

•vibration.

List of equipment

The following PPE equipment must be worn:

•fume mask – designed to filter out metal fumes

•gloves – heat- and cut-resistant

•welding mask – of a type that is specific to the welding process

•face shield – polycarbonate full-face screen

•ear protection – ear defenders or ear plugs

FUMES

All paint and electroplating should be removed from the surface of the metal panels to avoid toxic fumes being produced when these are burnt. A fume mask should be worn, or fume extraction used, where there is any risk of fumes being produced during the welding process. Avoid welding close to rubber seals or other combustible materials that are likely to give off noxious fumes when heated.

Fumes created during the welding of metals have been found to cause cancer and there are no guidelines at present as to what is a safe level of exposure. An air-fed mask is the best option if carrying out any significant amount of welding.

A range of leather gloves used for welding. Left to right: rigger glove; TIG welding glove; and heavy-duty MIG welding glove.

HEAT

When welding, gloves should always be worn to protect hands and wrists from burns. It is also necessary to protect arms from any burns that may be caused by weld spatter or contact with a hot panel by wearing suitable clothing. Short-sleeved shirts and short trousers should not be worn whilst welding or working on vehicle bodywork.

Gloves used for MIG welding should have a high level of heat resistance with long enough cuffs to protect the user’s wrists from burns caused by weld spatter that is given off from the process. TIG welding gloves require some heat protection, though need to be flexible enough to operate the torch trigger effectively.

ELECTRIC SHOCKS

Welding machines pose a serious risk of electric shock. Never use in wet, damp or high humidity conditions. Ensure that all cables are kept dry and in good condition. Machines should always be connected to the mains current through an appropriately rated electrical circuit breaker.

It is not advisable to carry out any welding outdoors due to the risks of electrocution and the likelihood of dispersion of shielding gas caused by draughts, as these will result in a poor-quality weld.

Polyurethane-coated gloves should be worn when using chemicals to protect hands from chemical burns and ingestion of harmful liquids through the skin.

INTENSE LIGHT CREATED BY THE WELDING PROCESS

It is important to protect your eyes. The flash of light from the welding process may cause temporary blindness and long-term sight problems if subjected to regular exposure. A suitable face mask is an essential piece of equipment for use during welding. There is a range of varying shades available depending on what type of welding is employed and the amperage used; a higher amperage will produce a brighter flash during welding, requiring a higher level of protection. Metals such as aluminium are highly reflective and a brighter flash will be experienced during the welding process.

There is a wide variety of welding helmets available. For MIG welding, a helmet with a light reactive lens is best, as this enables a clear enough vision of the joint prior to starting the weld. For TIG welding, a helmet with a passive lens is more useful; this lens is always shaded, but has a non-shaded clear area at the bottom of the screen. This clear section of screen enables the welder to see plainly the tightness of the joint before attempting to weld panels together. More detail will be covered on the different masks used for each process in the relevant chapter.

SHARP EDGES TO METAL PANELS

Suitable gloves that offer protection from cuts should always be worn when handling sheet metal. Gloves are available in a wide range of different designs and materials. Some offer more protection against cuts; others more protection from burns or a better grip. The best material that I have found to offer all-round protection and give a reasonable degree of grip is leather. The standard leather rigger glove, which has a safety cuff to protect the wrist, offers better heat protection than thinner welders’ gloves. Their disadvantage is in having less control over the torch button. The best of all worlds is to use a rigger glove on the hand holding the panel being welded to protect against burns, and a thinner leather glove on the torch hand to allow for more control over the welding control switch.

CHEMICALS

Chemical-resistant gloves must be worn when working with acids, thinners or paint to protect against the ingestion of chemicals through the skin and to avoid contamination of other surfaces.

A full face screen should be worn to protect eyes and face from splashes and a fume mask should be worn to avoid breathing in harmful fumes.

TRIP AND SLIP HAZARDS

Cables from extension leads, earthing leads and welding torches create trip hazards and should be kept as tidy as possible and put away when not in use.

Any dust produced during the grinding of metals creates a slippery surface when it falls on to a smooth concrete floor. Sweep up dust and filings at regular intervals to reduce the risk of injury from slipping on any debris.

MOVEMENT OF HEAVY OBJECTS

Gas bottles should ideally be stored ...

Table of contents

• Cover
• Title
• Copyright
• Contents
• DEDICATION AND ACKNOWLEDGEMENTS
• INTRODUCTION
• CHAPTER ONE: HEALTH AND SAFETY
• CHAPTER TWO: EQUIPMENT
• CHAPTER THREE: GENERAL PRINCIPLES OF WELDING
• CHAPTER FOUR: METALS
• CHAPTER FIVE: SPOT WELDING
• CHAPTER SIX: METAL INERT GAS – MIG
• CHAPTER SEVEN: TUNGSTEN INERT GAS – TIG
• CHAPTER EIGHT: FITTING PANELS
• CHAPTER NINE: FINISHING WELDED JOINTS
• GLOSSARY
• FURTHER READING
• INDEX