Miscellaneous Welding Recommended Guide for Shade Numbers
Operation Electrode
diameter inches 		Arc
current,
amps 		Minimum
Protective
Shade 		Recommended
Shade
Number
Shielded metal arc < 3 < 60 7 ---
3-5 60-160 8 10
5-8 160-250 10 12
> 8 250-550 11 14
Gas-metal-arc
welding 		  < 60 7 ---
  60-160 10 11
  160-250 10 12
  250-500 10 14
Gas-tungsten-arc   < 50 8 10
  50-150 8 12
Air-carbon-arc
cutting 		  < 500 10 12
  500-1000 11 14
Plasma-arc
welding 		  < 20 6 6-8
  20-100 8 10
  100-400 10 12
  400-800 11 14
Plasma-arc cutting   < 300 8 9
  300-400 9 12
  400-800 10 14
Torch brazing       3-4
Torch soldering       2
Carbonarc welding       14
  Plate thickness, in.      
Oxyfuel welding < 1/8     4-5
1/8-1/2     5-6
> 1/2     6-8
Oxyfuel cutting < 1     3-4
1-6     4-5
> 6     5-6