I would like to put 4 sections of 4-foot cast iron railing up in a "C" shape on our small concrete patio. (see here http://www.lowes.com/lowes/lkn?actio...573&lpage=none for an example of the railing I'm talking about.) This configuration will give us some privacy for sitting on the patio, as well as provide a place for us to hang planters. For various reasons, I do NOT want this to be a permanent installation -- in other words, I will NOT be bolting the post flanges directly into the concrete. My original idea was to custom-make a concrete formwork and pour five 12 x 12 inch, 2-inch-thick concrete bases to bolt the flanges to. Another idea was to bolt them into pressure-treated 2 x 12s and then find some kind of metal plate to make the bases heavier. Home Depot folks don't really think "outside the box" so saying something like, "I need something to bolt these into so the railings don't tip over" basically elicits a lot of blank stares.
Any ideas? How heavy/wide do you think the bases would have to be so this thing doesn't tip over?