TIG welding problem 1

[Trulli]

I'm TIG welding a steel trellis structure. When I weld in areas with good access I have no problem, but SOMETIMES, when I'm welding an inner joint with not very good access, the light from the tungsten electrode is much more intense than normal till the point that I must stop because I feel that the light would damage my eyes.
This never happens when the access to the welding area is good.
I use an autodarkening helmet that seems to work perfectly.
Is that normal? Why does it happen? Is there any way to avoid it?
Thank you.

 

[rd400guy]

Short answer, turn up the sensitivity on your helmet! It isn't recognizing the arc and so you're welding through a shade 3. It will damage your eyes if you keep doing this.

Most auto darkening helmets have a "normal" shade 3 or 2.75 that darkens when welding to anywhere from a 9 to 13 (if it's adjustable). I don't know what amperage you have your welder set at, I'm guessing pretty low (maybe ~25-30A?). When you're in a tight spot, sometimes the arc is long and you're not drawing full current. Or because of access, the arc is partially obscured from the helmet's sensor(s). Depending on the helmet, you may or may not have multiple sensors, or the helmet may not be designed for low amperage GTAW (TIG). In any case, it's not recognizing the arc. If you have a sensitivity adjustment, turn it all the way up, so that it will darken if you look at any bright light. This should solve the problem. If it doesn't you may have to use a conventional helmet with a 9 or 10 shade.

Hope this helps.

 

[Trulli]

Yes, the tube is thin wall and I use a low amperage.
You are right, I didn't realize that the problem was that the helmet didn't recognize the arc (probably because the bad access, because in normal weldings it works ok).
Thank you very much rd400guy, your anwer has been a big help!