Much cheaper to buy electrical enclosures than build them.
I get mine from either:

Hoffman Engineering
or,
Saginaw Controls

A few other good ones out there also.

Generally for outdoor control stuff, one would use a NEMA 4X rated enclosure.
(IP ratings are open to interpretation by the mfg)
You can fry DC stuff just as easily as AC stuff.
Guess it don't matter tho.

It would be interesting to see what ya got so far. The controller and all the stuff.