I had some 18 gauge 304 sheet and started putting together a glove box for an inert environment. The box is roughly a 30" cube with a slanted front for viewing. As I feared the sheet is too thin for the large size of the box. Even when it was just tacked it was sagging and wobbling. I decided to do the corner welds anyway. I didn't use any filler and they looked pretty good.

Now that I'm going to be spending some pretty good money on sheet, what gauge would be recommended for this size of box? There may be a slight vacuum applied when purging so it must be fairly sturdy. Also just don't want it to warp at all.

I was thinking 11 gauge, any thoughts?