RSG: The back wall cover would be a good idea, but my cabinet has an open grate on the bottom to place parts on, and an inverted pyramid type funnel below that to return the blast media to the hopper. What's below that grate gets the worst of it, particularly when working with smaller parts. So at a minimum it would need to be protecting the back wall and 4 sided funnel. But I'm pretty sure that paint on the other walls would be short lived just due to bounce back and other hits. And if that gets abraded away, then I'm right back into the "it will rust out even in Phoenix" territory. I think the only way I'm going to feel fairly confident about moving it outside is to paint it well, and then line the entire inside with something to protect the paint. Then only the grating will be at risk, but it's much heavier and would last longer than the sheet sides, and also easier/cheaper/quicker to replace (plus, nothing is going to protect that grate for long).