Welding safety

Welding arc eye

The light generated by MIG welding is extremely bright. Looking directly at a welding arc even for a split second causes arc eye when the bright flash from the arc burns the cornea. The cornea is very sensitive. Expect to be awake all night with the sensation that someone is sticking pins in your eye.

Even reflected light from the arc can cause arc eye under long exposure. Weld all day in a room with white painted walls and you could experience arc eye from light reflected against the walls going into the back of the helmet. Welders caps aren't just to stop sparks.

Be very careful to warn anyone else in the area when you are about to start welding, and use a welding screen if welding in an area where there might be passers by. Be especially careful with pets.

Metal vapor and your lungs

MIG welding and angle grinding results in metal vapors.

Aluminium alloy vapour and fumes from zinc coatings are poisonous. Exposure can result in heavy metal poisoning (welding shivers) - flu like symptoms that can persist for a few days, but can cause permanent damage. The zinc coating should be removed from galvanised steel before welding, and wear a proper charcoal welding mask when you go anywhere near zinc.

There's more detailed information about zinc fumes on the American Welding Society (see the pdf) and those with existing lung conditions might want to read about Jim's death by metal fume fever before welding galv.

It doesn't stop there - the fumes from flux cored gasless wire and ARC welding are nasty. Stainless gives off chromium, MIG and TIG arcs give off ozone. Welding should be carried out in a well ventilated area. Professional workshops normally have extraction systems. My approach is to leave the garage door open when welding. For prolonged welding It's a good idea to wear a vapour mask.

Protection from UV light and molten metal

The light from MIG welding has a strong ultraviolet content and causes sunburn (and of course skin cancer). Make sure that all of your skin is covered.

The weld is also likely to spit small blobs of metal out. Thick welding gauntlets protect the hands and wrists, and it is sensible to wear cotton overalls and take care not to leave gaps in your clothing or shoes where a blob of metal could enter.

The metal you weld stays hot for a while. Most of my burns have been caused by forgetting this and picking up a hot piece of metal in my bare hands.

Fire safety

Molten metal can spit several feet from a weld. Grinding sparks are even worse. Any sawdust, paper or plastic bags in the area can smolder and catch fire so keep a tidy area for welding. You think you'll notice flames but often you don't.

Keep a fire extinguisher beside the exit door from your workshop. CO2 is the best type for welding. A bucket of sand is also a good idea - it could save the expense of having the fire extinguisher refilled.

The photo shows a foam extinguisher (it contains water so it's not safe for use near electrical equipment like ...err... electric welders). It's since been replaced by a 2kg CO2 extinguisher. Don't squirt water or foam extinguishers anywhere near electricity for obvious reasons.

My extinguisher sits ready to use with the plastic tie removed. You'd be amazed how long it takes to figure out how to remove the plastic tie when you really need to. Fires spread quickly and you will be in a panic (been there)!

Angle grinding

Workshop tools are noisy and will damage hearing. I was lucky enough to be given some good advice by an almost completely deaf mechanic at the start of my career. He shouted "always wear ear protection when using a grinder, a hammer or even a drill".

Eye protection is important for grinding. Make sure you buy the expensive goggles with high impact lenses and without direct air breathing holes. The cheaper ones can let sparks in. Also always make sure the sparks are directed away from you as you grind.

Keep fire in mind as well. I've never started a fire due when welding, but have done a couple of times by not paying attention to where grinding sparks were landing. Clear up grinding dust too - aluminium dust mixed with steel dust burns so well it's actually used as a welding power source (thermite).