Hi David,
some ideas / questions:
> I was thinking about using sheet metal for everything
Pardon my ignorance, but how are you going to see what you are doing in there? Did you mean that one side is still acrylic? Front or top?
> airlock
If this is on the side wall, then it is probably hard to reach with your hands. On the other hand, the back wall (opposite of the gloves) is the most precious space you have and "wasting" it for the airlock is not good either...
A quick idea would be to attach the airlock at the bottom, with the outer door facing towards you and the inner door being a "trap door" in the bottom of the box.
> tools
If everything happens inside the box, space is even more precious. You'll need storage for the materials and chemicals, illumination stage, hot plate, spin coater, furnace, ... A rotating shelf on the back side might be a solution for that.
OTOH, an unsolved problem is be what the residual heat of the furnace is going to do to the acrylic box...
> gloves
Gloves always bring the danger of trapping hazardous chemicals *inside*, right next to your hands. You'll probably need a material that withstands *all* of those chemicals, otherwise you might have the piranha etch make the gloves porous and then HF leak through them... A simple warning not to spill anything over the gloves is probably not enough because these things just happen anyway.
Greetings,
Martin