David Billington wrote:

Sounds about what I would have said. I found there is a subtle change in
the surface of the aluminium before it drops on the floor, I learned to
recognise this and all went fine. I have never used anything other than
standard OA welding googles for Al and never had an issue with being
able to see what I was doing clearly. People mention using special
lenses to cut the flare from the glowing flux but I have never
experienced this. I have never welded Al with OA extensively and these
days would typically use TIG unless I had a benefit from using OA,
typically it leaves a more ductile weld which may be beneficial if you
are doing panel work.

You might want to try out the special lenses. They make a night and day
difference if you are Al welding (I couldn't imagine doing .025-.035
well without them). I don't find it as necessary brazing Al.