I had a very busy day today documenting the various stages the dome panels have to go through. Today I witnessed a wedge-shaped piece of aluminum-lithium go through a process called chem-milling. Basically it's using a caustic chemical to "remove" metal from certain areas instead of grinding or milling. This is done to shave weight from the item without sacrificing strength.
I am about 30 feet in the air on a manlift...
Here is the piece about to go in the tank.
The green is the masking agent
The silver part will be slightly eaten away
In the tank...
Whole lotta bublin' going on