New(ish) Enclosure builder Looking for some Advice

[The Serpent Merchant]

That was pretty much my plan as well, to build a frame though I was thinking a bit more along the lines of using angel ( was thinking 2 inch angle, 1/4" stock) dropping 1/8" pvc sheets into each "window frame" but the cost of the aluminum and the extra work required seemed like over kill.

I build competition robots, and all of the robot frames that I use are welded 3/4" 6061 Aluminum... so I already have the stuff laying around. Plus I'm talking about a cage for a retic/6 foot + monitor lizard, so the extra strength might be nice lol

For a BP, I would go with angle aluminum as well, riveted together.