Different Types of Welding
Light electric spot welding requires a lower shade lens than arc welding, so be sure to choose your shade lens based on the exact type of welding you will be performing. For light gas cutting and welding, around a number 5 shade should be sufficient, but even low amperes arc welding requires a shade rated around 10 or 11.
Amperes are another factor in what shade lens you should use. For up to 30 amperes, you should use shades rated up to 7. For 30 to 75 ampheres, use shades rated 8 or 9. For 75 amperes and above, you should use a number 10 shade lens or higher.
Testing the Shade Lens
It is important to test your shade lens to make sure you have chosen the right grade. To do this, place the lens in the helmet and look through it as if you were welding. To make sure the shade lens will be sufficient, look at a bare light bulb which has been switched on. If you can see the light bulb's outline, use the next shade darker and repeat the test again.
Shade Lens Safety
Never view the welding arc without sufficient eye protection. The first purpose of the shade lens is to diminish the visible light that you will see through the welder's helmet so there is no glare, but the other purpose is to protect your eyes from harmful infrared and ultraviolet radiation.