What the shade number means
A welding filter is graded by shade: the higher the number, the darker the lens and the less light reaches your eye. OSHA sets a minimum shade for each kind of work in 29 CFR 1910.133, from Shade 2 for torch soldering to Shade 14 for carbon arc welding, and it requires that a filter lens carry a shade number that fits the job.
The minimum is a floor, not a target. OSHA's own note to the table says to start with a shade too dark to see the weld zone, then go lighter until you can see it well, without going below the minimum. If two welders run the same machine at the same current and one sees the puddle better at Shade 11 than at Shade 10, Shade 11 is the right lens for that welder.
Arc welding and cutting: the OSHA minimums
Find your process, then the current you run. Electrode sizes for stick welding are the ones OSHA lists beside each current band.
| Process | Current | Minimum shade |
|---|---|---|
| Stick (shielded metal arc), electrode under 3/32 in | Under 60 A | 7 |
| Stick, electrode 3/32 to 5/32 in | 60 to 160 A | 8 |
| Stick, electrode 5/32 to 8/32 in | 160 to 250 A | 10 |
| Stick, electrode over 8/32 in | 250 to 550 A | 11 |
| MIG and flux core (gas metal arc, flux cored arc) | Under 60 A | 7 |
| MIG and flux core | 60 to 500 A | 10 |
| TIG (gas tungsten arc) | Under 50 A to 150 A | 8 |
| TIG | 150 to 500 A | 10 |
| Air carbon arc cutting, light | Under 500 A | 10 |
| Air carbon arc cutting, heavy | 500 to 1000 A | 11 |
| Plasma arc welding | Under 20 A | 6 |
| Plasma arc welding | 20 to 100 A | 8 |
| Plasma arc welding | 100 to 400 A | 10 |
| Plasma arc welding | 400 to 800 A | 11 |
| Plasma arc cutting, light / medium / heavy | Under 300 A / 300 to 400 A / 400 to 800 A | 8 / 9 / 10 |
| Carbon arc welding | Any | 14 |
Gas welding, cutting and brazing
Oxyfuel work runs much lighter than an arc. OSHA grades it by the thickness of the plate, and adds that a filter which absorbs the yellow sodium line of the flame is desirable for this work.
| Work | Plate thickness | Minimum shade |
|---|---|---|
| Torch soldering | Any | 2 |
| Torch brazing | Any | 3 |
| Gas welding, light | Under 1/8 in | 4 |
| Gas welding, medium | 1/8 to 1/2 in | 5 |
| Gas welding, heavy | Over 1/2 in | 6 |
| Oxygen cutting, light | Under 1 in | 3 |
| Oxygen cutting, medium | 1 to 6 in | 4 |
| Oxygen cutting, heavy | Over 6 in | 5 |
This is where a Shade 5 IR face shield window or a Shade 5 IR goggle lens fits: torch work, brazing and cutting with a flame. None of them is a lens for an electric arc, where the minimum starts at Shade 6 for the smallest plasma arc and at 7 for stick, MIG and flux core.
Helmet, hand shield or goggle
OSHA 29 CFR 1910.252 asks for a helmet or a hand shield in all arc welding and arc cutting except submerged arc, and goggles or other suitable eye protection for gas welding and oxygen cutting. A helmet or hand shield has to insulate against heat and electricity and keep the arc off your face, neck and ears.
A passive helmet carries a fixed filter plate in the window: the shade on the plate is the shade you weld at, and you lift the front or the whole helmet to see the work before you strike. An auto-darkening filter stays light until the arc strikes, then darkens to the shade you set. A fixed-shade auto-darkening filter darkens to one number, a variable one lets you pick inside a range such as Shade 9 to 13, which covers stick, MIG and TIG at most currents in the table above.
Plates, cover lenses and magnifiers
The filter plate does the protecting, the clear cover plates in front of and behind it keep spatter off the filter. Covers are the part you replace most: once spatter pits the outer cover, the view clouds and a new cover costs much less than a new filter. Size matters more than brand on these parts. The common window sizes are 2 x 4-1/4 in and 4-1/2 x 5-1/4 in, so measure the opening of your helmet before you order a plate.
A magnifier plate is a clear lens with a diopter rating that sits behind the filter. It helps you read the puddle up close; it is not a filter and adds no shade.
Each helmet, filter plate and cover plate for these shades has its own page in the Sellstrom lineup, with the shade and the plate size printed on it.
