The use of welder's glass for the direct observation of a solar eclipse is a topic that encompasses various aspects, including the nature of solar eclipses, the need for eye protection, the properties of welder's glass, and how it can be used safely for this purpose.

Understanding Solar Eclipses:

A solar eclipse is a celestial event where the moon moves between the Earth and the Sun, partially or fully obscuring the Sun's light. This phenomenon can be awe-inspiring but also poses risks if viewed without proper protection. The intense solar radiation, even during an eclipse, can cause serious eye damage.

The Need for Eye Protection:

Observing a solar eclipse requires taking precautions to protect the eyes. The Sun emits powerful ultraviolet (UV) rays, visible light, and infrared (IR) radiation. Looking at the Sun without protection, even during an eclipse, can lead to "eclipse blindness" or retinal burns, known as solar retinopathy. This damage can be temporary or permanent.

Welder's Glass as a Protective Tool:

Welder's glass is a type of darkened glass used in welding helmets to protect the eyes from the bright light and harmful radiation produced during welding. This glass is designed to filter out harmful UV and IR radiation and reduce the visible light intensity, making it a potential tool for safely observing solar eclipses.

Shade Numbers and Safety:

Welder's glass comes in different shade numbers, indicating the level of darkness and the amount of light it can filter. For solar eclipse viewing, a minimum of shade number 14 is recommended. This shade is sufficiently dark to protect the eyes from the intense light of the Sun. Using a shade lower than 14 is not safe for viewing the Sun as it does not filter out enough light and radiation.

Advantages of Using Welder's Glass:

1. Effective Protection: It offers strong protection against UV and IR radiation.

2. Affordability: Welder's glass is generally less expensive than specialized solar viewing glasses.

3. Durability: It is more durable than disposable "eclipse glasses."

Limitations and Considerations:

1. Optical Quality: The optical quality of welder's glass may not be as high as that of specialized solar filters.

2. Convenience:Holding a piece of welder's glass can be less convenient than wearing eclipse glasses.

3. Inspection for Damage: Before use, the welder's glass must be inspected for any scratches or damages, as these can compromise its effectiveness.

How to Use Welder's Glass for Eclipse Viewing:

1. Ensure Proper Shade: Use only welder's glass that is shade number 14 or higher.

2. Inspect for Damage: Check for any cracks or scratches. Even a small defect can allow harmful radiation to pass through.

3. Use Securely: Hold the glass securely or mount it in a way that it stays in place while observing the eclipse.

4. Avoid Prolonged Viewing: Even with protection, it's advisable not to look at the Sun for prolonged periods.

5. Never Use with Optical Devices: Welder's glass should not be used in conjunction with telescopes, binoculars, or cameras as these devices can concentrate the solar rays and cause damage.


Welder's glass, specifically shade number 14 or higher, can be a safe and effective tool for viewing solar eclipses. It provides necessary protection against harmful solar radiation. However, it's crucial to ensure that the glass is undamaged and used correctly. While it offers a practical solution, it's important to be aware of its limitations compared to specialized solar viewing equipment.

Roger Sarkis
Tagged: eclipse glasses