This is a good way to use recycled items and add color to your yard or flower pots.
Step 1: Select Cans From Your Recycling Bin
You can use any cans such as beverage or cat food/tuna cans. It is easiest and least dangerous with aluminum cans rather than "tin" (actually steel) cans used for canned vegetables. You can cut the aluminum cans with heavy ("kitchen") shearers, and handle them without getting cut on the edges (not really any more dangerous than getting paper cuts from paper). The tin cans are a whole other story needing tin snips and the edges are always sharp and dangerous.
Step 2: Make Yourself a Marking Guide
Wrap a strip of paper around a can and mark the circumference. Divide this by the number of petals you want, typically 5 or 6 and mark the paper at that interval. For the standard 12 oz beverage can or pint cans of the same circumference, that would be an interval of 1-3/8" (with the last petal being slightly narrower, but this is not critical). To make marking easier, I also make the paper strip height equal to half the can height. This makes it easy to to the next step of marking the can around its equator.
Step 3: Mark Beverage Can Around the Equator
Mark both the equator and the petal markings (e.g., 6 equally spaced locations around)
Step 4: Cut Can Around the Equator
Using a box knife, cut the can around the middle. Towards the end, the can will be losing its structure and may become difficult to cut.You can switch to the heavy shearers to cut the last bit, if necessary. Note, this cut does not have to be neat or precise. None of this edge will survive to the final result as petals will be coming to a point at this cut. Also, one doesn't have to cut precisely around the middle, as shown in this example. Some flowers look better with stubbier petals.
Note, for flat cans like those for tuna or cat food, you actually just mark the petal locations along the top edge of the can, rather than in the middle.
Step 5: Cut Petals
Using heavy shearers cut straight down to the base at each marking around. Then, cut the petals to shape. (Two different examples of petal shape are shown. These are not the only options. Be creative.) One shaped, bend the petals back to open up the flower. Optional at this point would be to curl the tips a little.
Step 6: Spray Paint the Flowers
First spray the backs, let dry a few minutes and spray the fronts. I prefer a glossy paint for these. Also, you can be creative and use multiple colors, applying a different color to the center of the flower or to the tips of the petals.
Step 7: Paint Flower Centers
I use a flat finish acrylic black for my flower centers, applying it with a brush. the can bottom/tops give you a guide to make perfect circles.
Step 8: Make Stems From Wire and Attach to Flowers
You can make stems from florist wire you get from a craft store, old wire coat hangers or my favorite is drop-ceiling hanging wire from my favorite craft supply house, Home Depot. I like to bend in the shape of a leave or two in the wire, plus a loop at the end where it will attach to the flower.
Attach the stem to the back of the flower using tape. I like to use metal foil tape, again from my favorite craft supply house.
Step 9: Display Your Flowers
Stick flowers in a bed around the house, or in a house plant pot. The examples show some possibilities with different size cans (e.g., the cluster of three yellow flowers are made from kitten food cans).