I just went to Google and entered pinterest tin can man and found tons of pictures that might inspire you on how to make one--some really cute ones! I have one half made--for more years than I care to think about--can't seem to make myself finish it!

i'd be afraid of getting cut, so be careful, those edges are pretty sharp yep-i think that's why they framed the top in the original plan. The edges are really sharp where i cut the tin so i faced them into the soil. The machine finished edge is a lot smoother so it is top side up. Carolynp and angela-thank-you! how exactly did you build it and what did it cost? had some 1.5" black PVC laying around. cut it into 24" lengths and pounded them a foot in the ground every two feet (you might be able to space them further apart). The tin panels were 2'x8'. I bought two and ripped them in half lenthwise and then ripped one in half crosswise using a jigsaw with a metal blade. (For my next bed i only need one panel since i have the ends left over from the first one.) Drilled some holes through the tin and PVC and bolted them together with galvinized bolts. I think tin was about $20 per panel but might be less in your area. Way cheaper than Trex which was the other material i was thinking about. The bolts were actually the most expensive part but you might be able to use only 1/2 as many as i did. One thing to remember is that the end panels have to be 1/2" lower or higher than the side panels so the corner bolts don't collide. Demeter-great idea!

this has a lot to do with if you can secure the new roof to the roof deck and that has a lot to do with how your house was built. Some metal roofing MUST be placed directly on top of a solid, smooth, roof material. Others can be installed with an air gap between the old roof and the new metal roof. Wood strips (purlins) are placed over the old roof and attached securely to the roof deck. The new metal roof is then attached to these wood strips. I think this would be possible for you to do. However, I would think that maybe removing the roof would be worth your while, as you may get some money for it because many metals are very expensive right now and companies are willing to buy and recycle it. Removing a metal roof would be easier than removing an asphalt roof also.

I stand corrected about tooth paste tubes. Presently, those are made of plastic or plastic with other material layers. I fault my memory. I'm too old. I do remember aluminum tooth paste tubes and according to several articles, manufacturers sought alternate materials for the tubes during WW2. http://www.intelligentdental.com/2011/09/18/about-toothpaste-tubes-made-of-metal/ Metal tubes did not entirely disappear. Those are used to hold materials that may be incompatible with plastic. I recall 2 yrs ago, getting a tiny tube of medication that was in a metal tube. In recent times, have seen lubricants, artist paints, and adhesives in metal tubes. The article below states that tooth paste tubes were made of a tin-lead alloy up to WW2. It was suspected that lead might have been bad for health (depending on how much leached into the paste) and by WW2, the tube material was changed to aluminum, some with coatings and other layers. During WW2, a push was made to eliminate aluminum in tooth paste tubes as the war effort restricted the supply of aluminum to the general public. Another tooth paste tube article. The link below shows that tooth paste type of tubes (for packaging) are are available in several materials including metal. https://www.alibaba.com/showroom/toothpaste-tube.html