How do you take off the keyboard from the top case?

I know that the late 2010 MacBook Air's such as the A1369 13" model and the 11" A1370 model both have the keyboard welded or soldered on to the top case. I know there are screws holding some part of the keyboard. I dont even know why they even bother putting screws on, they might as weld/solder it all the way through.

My question is does anyone know how to properly remove the keyboard off the top case assembly or how to un-weld or desolder the keyboard off the top case? Also, how would one get it back on. This kind of manufacturing is also seen in apple's wireless keyboard where the keyboard is also welded to the chassis.

No thanks to apple for allowing such a restrictive manufacturing design . Wasting all that aluminum just because the keyboard goes bad.