On Thursday, February 13, 2014 6:39:33 AM UTC-5, John B. wrote:






Somehow I get the feeling that you've lost the thread. You tell me

that some sort of fancy glasses let you see the heat when you weld

aluminum; I ask you how that works, and now you are off and running

with non-UV lens.



But how does all this let you see the heat of aluminum when you are

gas welding it?

--

Cheers,



John B.

I think it is because the flux has sodium in it and when heated gives that yellow sodium vapor light. Cobalt lenses filter out the yellow sodium light and lets you see the aluminum clearly. So it is no miracle cure for welding, but it does let you see.

When you heat the aluminum, the outside oxidizes and the oxide covers the shiny melted aluminum. So you just keep poking at the aluminum with the rod and when you get some melted aluminum the rod pushes the oxide to one side and lets you see the melted aluminum.

Dan