March 14, 2018
I see a lot of fellow welders comment about how the headgear always fails on the plastic knobs and this must be a design flaw, etc. However, I am under the impression after reading all of these reviews that most of the commentators actually do not know how to correctly use their Speedglas hood, nor did they obviously read the manual the hood came with (I know, who reads those things?).
I just wanted to comment that the knobs on the Speedglas 9100 series, and I believe most other series, have 2 separate functions. That is to say that the 2 knobs each do something different, and I think most people just blatantly over-tighten them in order to make the hood stay up, when in fact it is not being used correctly.
The knob on the left side of your head when the hood is on controls the force it takes to lock the hood up and open or closed and down. Making this left knob tighter makes the hood harder to click up into the locked position, and making it looser makes it easier for the hood to fall down. Too loose, and the hood will just always slide down, and not lock up at all. So first you must make sure your left knob is adjusted correctly and that the hood can go up and lock up, but that it's not too stiff to not close when you nod your head to strike an arc.
The knob on the right side controls the friction resistance of the sliding action of the hood as it moves up or down. This means that the tighter the knob, the harder it is to slide the hood up and down relative to the headgear while its on your head. Too tight and you cannot get the hood to come down without grabbing it and pulling, and too loose and the hood falls too fast when you unlock it to lower it.
I believe most people just crank the right knob down until it is tight enough to almost hold the hood open, and possibly do the same with the left knob thereby making it impossible to actually lock up the way it was designed. I hope this helps some fellow welders out there, because its a shame to hear people are misusing something that is actually so well made and better than anything else I have ever used, and owning a welding shop, I've used a lot.