How Bright Is a Welding Arc?

Written By: Liam Bryant

Reviewed By: Russell Egan

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Welding arcs can emit an intense amount of radiation and light. They’re bright and hot enough to cause significant eye and skin damage to long-term professional welders.

The hazards of being a welder include the risk of being exposed to both seen and unseen rays. It’s imperative to familiarize yourself with these welding hazards as a safety precaution.

How Bright Is a Welding Arc?

A small 90 amperes welding machine needs at least 3000 watts of power to run, and it’s more than capable of producing an extreme amount of visible light.

For reference, your LED light bulbs can produce around 2600 lumens at 27 watts. This lumen estimate gets brighter with higher wattage.

We can safely assume that your average welding arc can produce visible light many times more intense than your brightest LED bulbs.

bright mig welding arc

UV Radiation

Ultraviolet (UV) radiation is a type of electromagnetic radiation (EM) energy.

When you heat a matter to an incandescent level, it emits high-frequency energy. The wavelength of ultraviolet light is less than that of visible light. That’s why the human eye cannot detect it. You can only see this emission with specialized equipment.

Your welding arc emits visible light, infrared, and ultraviolet radiation. This happens when the electrode makes contact with the workpiece and creates an electric arc.

Which UV Rays Are Harmful to a Welder?

The welding arc emits the entire ultraviolet spectrum.

You can classify the UV rays produced by your soldering arcs into UVA, UVB, and UVC rays.

UVA (ultraviolet A) has the least amount of energy of the three. This ray has the ability to penetrate the dermis or the middle layer of your skin. It’s also linked to skin aging.

UVB has slightly more energy than UVA. It can reach the outer layer of your skin. Research has linked this UV to sunburns and cataracts.

Long-term exposure to both UVB and UVA rays can increase the risk of cell and genetic defects, such as cancer.

UVC rays are the most potent among the three types of UV. If you directly expose yourself to this radiation, it can cause burning on the skin and eye problems, like welders flash.

What Is Welder’s Flash?

Welder’s flash is the swelling of your eye’s cornea caused by extended and close exposure to ultraviolet radiation. 

It happens when you fail to properly protect your eyes from penetrating light from your arc. This condition is very common in welders and lasts 1 to 2 days.

They also call welder’s flash by several other names. You might hear people saying flash burn, arc-eye, snow blindness, UV burn, or photokeratitis.

Here are the typical symptoms to watch out for:

  • Headache
  • Sensitivity to light
  • Bloodshot eyes
  • Sensation of having “sand” in your eyes
  • Mild to moderate eye pain
  • Eye-watering
  • Blurry Vision
  • Inability to open your eyes

You can prevent developing a welder’s flash by wearing appropriate eye protection while welding.

Some professional welding industries even require welding screens and curtains to protect onlookers and passersby.

If you did contract welder’s eye, there are things you can do to cure or at least alleviate its symptoms.

Eye drops

You can try using non-steroidal anti-inflammatory eye drops to reduce the swelling of your eyes. Some physicians might also prescribe eye dilating drops to relieve and soothe eye irritation.


Rosewater contains antibacterial properties and is effective for eye conditions. It would help lubricate your eyes to boost the healing process.

Drip a few drops of rose water using a spoon or a cotton ball into the affected eye. Apply it twice a day for a few days until it heals.

Keep in mind that the rosewater remedy doesn’t eliminate the need for medicated drops.


You can also use your cucumbers as a remedy to alleviate your eye’s inflammation caused by the welder’s flash.

Take your cucumber and cool it inside your refrigerator for a few minutes. After cooling, take two moderately thin slices of the cucumber and place them over your eyes for a while.

This method will mostly soothe the area around the eyes. You might still need medicated drops.

Protect Yourself From UV Radiation

I know gearing up before starting the welding machine can be tedious, especially for smaller projects.

It’s still necessary if you’re a regular welder. This is to prevent the health risks that come with arc welding, like eye diseases and skin cancer.

Here are the items you must wear every time you weld:

Always Wear Your Welding Goggles

Your welding goggles are specifically designed to reduce the glare of the welding arc.

This means that the amount of ultraviolet and infrared light that reaches your eyes will significantly decrease.

Put On Your Welding Helmet

Welding helmets or welding hoods are made to protect both your eyes and your skin from the harmful effects of arc radiation.

They can cover a larger area than the goggles but can be uncomfortable for some welders.

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Wear a Welders’ Jacket and Apron

Welding aprons and jackets shield your body from burning caused by direct contact with heated metals or flying sparks.

It will also reduce the area of your skin exposed to UV radiation.

I personally prefer a welding jacket like this one by Lincoln Electric. It is designed especially for high-amperage welding and out-of-position welding. It has a two-part armpit design that actually allows you to move your arms which is much more comfortable than the old-fashioned leather jackets.

Lincoln Electric Welding Jacket

Apply Sunscreen Before Welding

Sunscreens protect your skin from sunburns and tanning from constant welding heat.

They are also well-known for their ability to deflect harmful UV rays that may penetrate your skin. This can minimize the possibility of developing skin diseases in the long term.

Make sure to put it 15-20 minutes before you start welding.


Learning the brightness of a welding arc is just the tip of the iceberg. Welders are already aware that arcs can generate powerful light fluxes.

Your welding machine also releases ultraviolet and infrared light as it creates the arc. Long-term exposure to the high levels of UV radiation generated by welding can cause welder’s flash and skin burns. It also puts you at risk of skin cancer.

Remember that proper protective welding gear consists of goggles, helmets, and aprons.