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Why TIG needs careful sensitivity adjustment
TIG arcs can be dimmer than the arcs from MIG or stick welding, especially at low amperage. A helmet set to low sensitivity may fail to darken reliably, or it may flicker between light and dark as the arc starts and stops. That is distracting and can expose your eyes to an uncomfortable flash. Setting sensitivity too high has its own drawback: the helmet may darken in response to nearby welding, bright sunlight, or reflections.
Sensitivity controls how readily the helmet’s sensors trigger the darkening filter. It does not set the shade level. Shade controls how dark the lens gets after it triggers; delay controls how long it stays dark after the arc ends. Adjust each control for its job.
Start with the right setup
Before changing sensitivity, check the helmet’s manual for its adjustment method and sensor requirements. Place the helmet in its welding mode, set the correct shade for your process and current, and make sure the battery is fresh or the solar-powered unit has had enough light to charge. Inspect the outside and inside cover lenses: spatter, scratches, or grime can obstruct the sensors or make the view harder to judge.
For a starting point, set sensitivity around the middle of its range. With many helmets, that is roughly halfway between low and high, but dial markings and behavior vary. Start the TIG arc on scrap at the current you intend to use, with the helmet in its normal working position. Do not test by staring at an unfiltered arc or deliberately exposing your eyes to flashes.
Adjust sensitivity step by step
If the lens does not darken consistently at arc start, raise sensitivity a little and repeat the test on scrap. Continue in small steps until the filter triggers reliably. If it darkens from another welder’s arc or bright reflections when your own arc is off, lower sensitivity one step at a time. Aim for reliable triggering without nuisance darkening—not the highest setting.
Keep the helmet and workpiece in the positions you will use on the job. Sensors can be blocked by the torch hand, a tight joint, or the edge of a fixture. If the lens fails only when your head is turned or the sensors are partly covered, adjust your position or use a helmet with sensor placement and sensitivity suited to the work. Do not assume a higher setting can compensate for every blocked-sensor problem.
After sensitivity is stable, set delay to suit the job. A short delay helps when making quick tack welds; a longer delay can be more comfortable at higher current, where the weld remains bright after the arc stops. If the lens clears while the pool is still bright, increase delay. If it stays dark longer than useful between short welds, reduce it.
Settings by welding situation
These are starting points, not guaranteed dial positions. Helmet controls are not standardized, and sensor design, room lighting, and arc conditions all matter. Check the helmet manual and use the manufacturer’s shade guidance for your amperage. Never lower the shade below the level recommended for the current and process just to get a brighter view.
| Situation | Sensitivity starting point | What to watch for |
|---|---|---|
| Low-amperage TIG, roughly 5–40 A | Medium-high to high | Missed starts or flicker; raise sensitivity if the arc is not detected consistently. |
| General TIG work, roughly 40–150 A | Medium | Confirm reliable triggering from your actual torch position and working angle. |
| Several people welding nearby | Medium-low, if your arc still triggers reliably | Nearby arcs may cause unwanted darkening; reduce sensitivity only as far as dependable triggering allows. |
| Outdoor work or strong reflected light | Medium or lower, after testing | Sunlight and reflections can trigger some helmets. Change your orientation or block the reflection if needed. |
Amperage ranges are broad examples, not a promise that every helmet will behave the same way. A small, low-current arc is generally harder for sensors to detect than a brighter one. If you often TIG at low amperage, compare helmets with adjustable sensitivity and multiple sensors; a basic fixed-sensitivity helmet may be less dependable for that specific work.
Common problems and practical fixes
The lens stays light at arc start: Raise sensitivity, confirm the helmet is in weld mode, and check batteries and sensor windows. Try again on clean scrap. If it still fails, stop using the helmet for welding until you have corrected the fault or replaced it.
The lens flickers during the weld: Check whether your hand, torch, or a narrow joint is blocking a sensor. Clean or replace dirty cover lenses, make sure the helmet sits securely, and test with the workpiece positioned as it will be in use. Raise sensitivity only if the sensors have a clear view and triggering is still unreliable.
The lens darkens when someone else welds: Lower sensitivity slightly, move away from the other arc, or change the helmet’s angle. If your own low-current TIG arc then fails to trigger, restore the setting and use a different position or helmet rather than accepting missed starts.
The view feels too dark: Check the shade setting, not sensitivity. Also inspect the cover lenses and make sure the helmet’s shade range suits your work. If you cannot see the joint clearly at the required protective shade, improve task lighting and fit-up instead of reducing protection.
Choosing a helmet for TIG
If you TIG occasionally at moderate current in a quiet shop, a correctly functioning entry-level auto-darkening helmet can be enough. Pay attention to shade range, a reliable manual, replaceable cover lenses, and available replacement batteries—not just extra features. For frequent low-amperage TIG, a TIG helmet with adjustable sensitivity gives you more control over difficult starts and nearby arcs.
Multiple sensors can improve detection when a sensor is partly obstructed, but they do not make a helmet immune to every blocked view or bright reflection. A larger viewing area can make joint tracking easier, at the cost of greater weight or price on some helmets. If your helmet repeatedly misses the arc despite clean sensors, good batteries, and correct settings, stop using it and replace or service it. Sensitivity adjustment is not a substitute for a dependable lens.
Before each session, check that the helmet is in weld mode, the correct shade is selected, the sensors are clean and unobstructed, and the lens darkens reliably in a controlled test on scrap. If you see a flash or the filter behaves unpredictably, stop, identify the cause, and do not continue until the helmet protects consistently.