| Operations | Electrode Size 1/32 in. | Arc Current | Minimum* Protective Shade
|
|---|
| Shielded metal arc welding | Less than 3 | Less than 60 | 7
|
| 3-5 | 60-160 | 8
|
| 5-8 | 160-250 | 10
|
| More than 8 | 250-550 | 11
|
| Gas metal arc welding and flux cored arc welding | | Less than 60 | 7
|
| 60-160 | 10
|
| 160-250 | 10
|
| 250-500 | 10
|
| Gas Tungsten arc welding | | Less than 50 | 8
|
| 50-150 | 8
|
| 150-500 | 10
|
| Air carbon | (light) | Less than 500 | 10
|
| Arc cutting | (heavy) | 500-1000 | 11
|
| Plasma arc welding | | Less than 20 | 6
|
| 20-100 | 8
|
| 100-400 | 10
|
| 400-800 | 11
|
| Plasma arc cutting | (light)** | Less than 300 | 8
|
| (medium)** | 300-400 | 9
|
| (heavy)** | 400-800 | 10
|
| Torch brazing | | | 3
|
| Torch Soldering | | | 2
|
| Carbon arc welding | | | 14
|
| Operations | Plate thickness- in. | Plate thickness- mm | Minimum* Protective Shade
|
|---|
| Gas Welding:
|
Light| Under 1/8 | Under 3.2 | 4
| Medium| 1/8 to 1/2 | 3.2 to 12.7 | 5
| Heavy| Over 1/2 | Over 12.7 | 6
| | Oxygen Cutting:
| Light| Under 1 | Under 25 | 3
| Medium| 1 to 6 | 25 to 150 | 4
| Heavy| Over 6 | Over 150 | 5
| | | | | | |
Source:29CFR1910.133(a)(5).
* As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade which gives sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding or cutting where the torch produces a high
yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light of the (spectrum) operation.
** These values apply where the actual arc is clearly seen. Experience has shown that lighter filters may be used when the arc is hidden by the workplace.
