ESAB G40 Air 90 x 110 Parts FAQs
Spare lenses, gaskets, headgear, sweatbands and shell parts for an air-fed welding helmet, and how to choose and look after them.
What is the difference between the outer lens and the filter lens?
The filter lens is the dark glass that cuts the arc's light and ultraviolet and infrared radiation to a safe level. The outer lens is a clear, easily replaced sheet in front of it that protects it from spatter, pitting and scratching.
The outer lens is meant to be changed often so the filter lasts. Some helmets also have a clear inner retaining lens behind the filter. A cover is not a substitute for a filter, and a filter must never be left out. Check your manual for which lenses your helmet uses and in what order they fit.
How do I choose the right shade of filter lens?
A higher shade number means a darker filter that lets less light through. Passive welding filters are graded by shade number, and the requirements now sit in a newer international standard series, which replaces the older European filter standard for new certification. Older helmets may still carry the older markings.
The shade you need depends on the process and the welding current. Shade charts give higher shades for higher currents, with plasma cutting covering a wide range. A common tip is to start with a shade slightly darker than you think you need, and move lighter within the recommended range only if the weld pool is hard to see. Follow your helmet manual and risk assessment.
How do I check that a replacement filter lens will fit my helmet?
Filter lenses are made in set sizes, written as width x height in millimetres, so the replacement must match the size your helmet's holder was made for. Check the thickness and shade as well as the nominal size.
Read the markings on the old lens and on the helmet. Helmet frames used to be covered by an older European standard, which has been replaced by a newer international standard series for new certification, so older helmets may still show the old marking. Lens markings show details such as the shade and manufacturer. If markings are worn off, use the helmet manual or measure the old lens, and ask our team if you are unsure.
What are the lens gasket and lens cradle for?
The lens cradle is the frame or holder that the filter lens sits in inside the helmet front. The gasket is a thin seal that usually sits between the glass and its holder so the lens is held without rattling and without being stressed.
If the helmet uses a gasket, it should be replaced periodically, and whenever it is flattened, torn or missing. Check that the lens sits flat and secure, with no gaps that could let stray light reach your eyes. Do not use a cradle that is cracked or deformed. Which parts your helmet has, and how they fit together, is shown in the manual's parts diagram.