Make walls thinner?

[joshpigford]

How would I make the walls of this solid body thinner? Right now the walls are roughly 10mm and I'd like them 5mm.

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That's in a sliced analysis view (the other half is a mirror of that).

I've attached the f3d file.

[joshpigford · Accepted solution]

Figured out how to do it. Had to manually select all of the outside faces (45 of them!) and then do a press/pull of 5mm.