Straight answers to the questions people ask most when choosing and using a welding helmet.
What is the difference between a passive and an auto-darkening helmet?
A passive helmet has a fixed dark filter, so you flip the helmet down or lower the visor just before you strike the arc and lift it afterwards. An auto-darkening helmet has a filter that is clear when you are not welding and darkens in a fraction of a second when the arc starts.
Auto-darkening helmets let you see the work before you weld, so you can position the electrode or torch accurately without lifting the helmet. Passive helmets are simpler, lighter and have nothing to fail electronically, and some people prefer them for heavy or fast work.
What do the optical class ratings on a helmet mean?
Many helmet filters are marked with four numbers that grade optical quality, covering clarity, light scatter, evenness of darkness across the lens and how the view changes when seen from an angle. Lower numbers are better, and the best possible rating is shown as 1/1/1/1.
A higher grade gives a clearer, less tiring view, which matters when you weld for long periods or do fine work such as TIG on thin material. Check the markings on the filter and the maker's instructions for what they mean.
What is the difference between a fixed shade and a variable shade filter?
A fixed shade filter darkens to one level, for example for one particular job. A variable shade filter lets you set the darkness within a range, so one helmet can be used for several processes and currents.
Variable shade is the usual choice if you do different kinds of welding, or welding at different currents, because you can adjust the shade to suit the arc and your eyes. Fixed shade is simpler and suits repetitive work that is always the same. The shade you need depends on the process and the current, so follow the maker's guidance.
Does it matter how many sensors the helmet has?
The sensors detect the arc and tell the filter to darken. More sensors can help in awkward positions, where a single sensor might be blocked by your hand, the workpiece or a fixture, so the filter fails to darken.
This matters most when you weld in tight spaces, out of position or at low current. For general work in the open, a helmet with fewer sensors is often perfectly good. Whatever the number of sensors, always check that the filter darkens before you weld.
What do sensitivity and delay controls do?
The sensitivity control sets how much light it takes to make the filter darken. Setting it high helps with low-current work such as TIG, where the arc is dim. Setting it low stops the filter from reacting to bright light from other welders nearby or from the sun.
The delay control sets how long the filter stays dark after the arc stops. A longer delay protects your eyes from the glowing hot metal after a high-current weld, and a shorter delay lets you see the work again quickly between tack welds.
Can I wear glasses under a welding helmet?
Yes. Most helmets leave enough room for ordinary glasses, but check that the helmet fits comfortably and that the glasses do not push the headgear out of position or let light leak in. Some people find it works better to adjust the headgear so the helmet sits slightly further from the face.
If you find it hard to see the weld clearly, a magnifying lens, often called a cheater lens, fits behind or inside the filter in many helmets. Make sure the lens is made for your helmet and is fitted as the maker describes.