Welding is the process of fusing metal together at high temperatures so that individual pieces of metal become a simgle piece of metal. Thermoplastics that can also be fused together with welding processes.
Types of Welding
Gas Welding
Oxyacetylene welding uses acetylene gas and oxygen that combine together in a torch to create a very hot and concentrated flame. This flame is hot enough to melt steel and provides some protection from atmospheric impurities. An oxyacetylene torch is also commonly used for Brazing and the cutting of thick pieces of metal.
Electric Welding
Stick Welding Mig Welding TIG-Welding uses a hand held electric torch with Tungsten electrode to heat and melt the metal. A filler rod is used to complete the weld.
Cleaning Metal for Welding
If metal to be welded is not clean then the weld will not be sting and may need to be redone or the entire fabricated part might need to be discarded in mission critical situations such as aviation or nuclear power plants. In other less technical welding applications it is still necessary to properly prep and clean surfaces before welding. This will ensure proper penetration of the weld and fusing of the base metals.
Metal can have paint, oil, mill scale, rust, contaminates, weld spatter and many other imperfections that will prohibit a proper weld.
Cleaning mild steel with acetone can remove many contaminates. Metal should be cleaned of contaminates before sanding so the contamination is not ground deeper into the material. Aluminum requires special precautions to avoid weld contamination including keeping a set of prepping tools only used on aluminum and not other metals.
Removing rust and paint can be done with sandpaper, sandblasting, a wire wheel, or an angle grinder. Only use a grit that is just course enough to remove unwanted material without making deep grooves. Finer grits should be used to make the surface smooth since scratches and grinding groves can trap contaminates that will ruin a weld.
When TIG welding it is also important to wipe down and clean the filler rod before welding.
Weld Mistakes to Avoid
- Cold Lapped Welds
- Undercutting of Base Metal
- Incomplete or Too Deep Weld Penetration
- Incorrect Weld Bead Width
- Cracks in the Weld
- Contaminate Inclusions in Weld
- Incorrect Filler Rod
- Incorrect Gun Angle
- Too much stick out or distance from the material to the mig gun
Vertical Welding Mig Tips
- position material so where you are welding can be seen the entire time you are welding, putting the piece a bit lower can help
- Keep the MIG gun close enough to the weld
- Keep the MIG gun angle correct since the tendency will be to have gravity and and your desire to see the weld puddle to pull the gun angle down
Welding Safety
- Always Inspect Welding Equipment Before Use to ensure it is in proper working order and all safety devices and materials are in place and not damaged.
- Always wear safety glasses in addition to a face shield when grinding, one or the other is not enough, use both. Small bits of metal can bounce off you then your face shield and then your eye.
- Avoid touching random pieces of metal and assume that everything is extremely hot and sharp
- Clean metal before welding to make better welds and to remove harmful contaminates that might vaporize and be inhaled
Respiratory Safety
Welding creates very fine particulate matter when the base material and filler material are vaporized and melted. Exposure to airborne manganese has been linked to neurological disorders with symptoms similar to Parkinson’s Disease. The smallest particles and fumes produced from welding can remain suspended in the air for hours or even days in shop air after all welding has stopped.
PPE is a secondary defense after environmental ventilation controls.
- Keep your head out of and away from the smoke plume created from welding
- Wear a minimum of a P100 respirator at all times to reduce fume inhalation
- Have adequate venting of the work area
- Keep fume extractors as close to the plume as possible
- Store respirators in closed containers away from dust sources
- Clean and disinfect respirators regularly
- Change filters on a schedule or when breathing becomes impaired
Workspace Safety
- Watch for trip hazards caused by the numerous cords and hoses required for metal work
- Pause to clean up and organize loose cords, hoses, tools and materials as soon as a task is finished to minimize tripping hazards and dangerous environmental hazards
- Don’t allow cables to wrap around your body
- Keep everything dry to avoid electrical shock
- Know where the grounding clamp is connected at all times
- Treat all welding equipment as if it were energized
- Remove any and all chlorinated solvents from the work area to prevent deadly phosgene poisoning
- Use only rubbing alcohol, acetone, or water based alkaline cleaners
Radiation and Burn Safety
- Always completely cover all skin when welding to prevent arc burns and skin cancer
- Always wear gloves when welding
- Never wear gloves when using rotating power tools or other rotating equipment, glove will get caught and pull your hands into the mechanism
- Always be aware of your surroundings, especially when working in a shared environment
- Never wear synthetic materials such as nylon or polyester since these fabrics will melt with enough heat and then stick to your skin causing severe burns
- Never wear synthetic shoes or open toe shoes, leather shoes with high tops offer the best foot protection, from spatter and molten slag droppings
- Wear long pants
Grinding Safety
- Never remove the guard or handles from an angle grinder
- Always use the handle with your second hand
- Never exceed the rated RPM of the grinding wheel
- Inspect every disc or wheel before use or mounting. Never use dropped or damaged grinding wheels
- Wear proper safety glasses AND a full face shield, glassed protect your eyes and a shield protects your face
- Wear hearing protection
- Wear leather gloves
- Wear proper respiratory protection
Welding Safety Articles
Welding Safety for Students: The Complete Guide to Staying Alive in the Shop . The Weld Room, Cooper Bridge USA, March 10, 2026.
Controlling Hazardous Fume and Gases during Welding OSHA Fact Sheet.
Bhandari, Tamara. Low levels of manganese in welding fumes linked to neurological problems . Washington University School of Medicine, December 28, 2016.
Guerrero, Rafael. Are Nonwelders in Your Shop at Risk from Welding Fumes? The Welder, January 26, 2024.
Brouk, Tim. Purdue Health Sciences researchers spark importance for welder safety from toxic particles in fumes . Purdue University, February 6, 2025.
Welding Symbols
Welding symbols are used to communicate the desired weld process, location, and technique for a particular design. They allow an engineer or designer to accurately communicate to the welder what needs to be done.