For those of you familiar with me on here, I appreciate you sticking around to help.

New project, new problem.

I've been given some (full-sized) models by a company. I'm supposed to scale them down, but also make them printable through FDM.

Not too big a deal I figured, scale it down, and go with it, but none of these pieces are thick enough to be worked with. I'm trying to thicken them up, but the thicken command won't stop being grayed out.

I've even attempted an outward shell (just as a thought), but that causes the program to crash before I can even get a preview.

I've attached a few pieces of the model (the whole thing is way too large to attach sadly). I'm on 2017.

Thanks in advance for any help guys.

edit: I added a few parts instead of an assembly, due to size constraints on uploads.