Needed an 8x10 printing frame and really wasn't up to waiting a week for mail order. So, started with a wooden picture frame and re-enforced the corners. Made a backing board that has black felt affixed to the inside. And then I made the "Great Discovery". Aluminum bar stock when bent into a curve retains the curve indefinitely (or for a very long time). So, I shaped the aluminum bar stock into a curve by hand using a coffee can as a form. Everything else is history.