A while back, somebody jokingly proposed that I make a pair of chainmaille sandals. This is what I came up with - I replaced the straps on a pair of flip flop with elastic, and then sewed on strips of chainmaille. Of course, you could put anything on the straps, or leave them plain.
Step 1: What You Need
First, you need a pair of flip flops. Importantly, the straps must be the type that is made of plastic and held onto the sole by plastic disks. The straps need to not be glued into the sole, because you're going to remove them. If you look at the picture, you can see that the plug at the bottom of the strap can be pulled out.
(I got 2 pairs for $5 at Old Navy.)
Next you need some elastic. You'll want the elastic to be narrow and soft enough that you can easily tie it into a knot. I'm using black fold-over elastic which I happened to have sitting around.
You'll also need some glue. I'm using Gorilla super glue, which seems to work. (I don't know that much about glue, though, so if you have other suggestions, please comment.)
Step 2: Make New Straps
To make the new straps, first cut off the old ones. Keep the plugs - you'll need them later.
The new strap arrangement has a long loop which will go from between your toes to behind your heel, and a short strap which goes across the middle of your foot. For me, the long strap was about 14 inches, plus each side needs 1/2 inch for the thickness of the sole, so 15 total. The short strap is about 5 1/4 inches plus 1/2 inch on each side, so 6 1/4 inches total. However, you will need extra length for tying knots, and you may need different strap lengths.
I recommend that you take a long length of elastic and tie off the length for the long loop (folded in half mine was 7 1/2 inches). Do not cut it off yet! Now, thread it through the hole at the toe of the sandal and try it on your foot. If the strap seems long, undo the knot and try a shorter length. Keep doing this until you are happy with the length of the main strap. Now, cut the elastic off just below the knot.
For the short strap, tie a knot in the end of the elastic. If your elastic is very long, cut a length that is longer than you will need (mine was 11 inches or so). Now feed the elastic through one of the holes at the side of the sole (from bottom to top), and then feed it through the other hole (from top to bottom.) At this point, put your foot through the strap, and pull it until it seems tight enough. Keep hold of the point where the elastic goes into the hole (or attach a safety pin). Take the strap off your foot and tie a knot at the point you just marked. Now you can cut off the elastic below this knot.
Try the sandal on with both straps, and adjust the length if necessary. Then make two straps the same length for the second sandal. (You'll have to measure the strap from the point where it goes into the sole, and then add double the thickness of the sole.)
Step 3: Glue It!
Once you have all the straps constructed and threaded through the holes in the sandal, it's time to glue them down.
Find those plastic plugs from the ends of the straps. If there's any strap left attached to them, cut it down so you have just a disk. (It doesn't have to be very accurate - I just cut it as close as I could with an ordinary pair of scissors.)
Push each knot down as much as you can without pushing it through the sole. Cover the knot in glue, and push a disk down on top of it. Push down really hard until the glue sets. (You'll probably want to use a piece of cardboard or something for this so that you don't glue your fingers.)
Step 4: Add Embellishments
At this point, you can go ahead and wear the sandals. The long strap goes behind your heel, but it can go either on top of or underneath the short strap.
However, you can also add anything you like to the straps. I attached 4 strips of helm chain with a needle and thread. (I sewed a line down the middle of the elastic, doing several loops around the sides of the rings at the ends and the sides of each orbital ring. This does mean there's a line of stitching on the back of each strap which is visible if you look closely, but the back of the strap isn't visible while you're wearing the sandals.) Because the chainmaille extends past the short strap, I'm wearing them with the long straps on top.
Some other ideas: sew on beads, sew on strips of decorative ribbon, add eyelets, sew on fake flowers... The possibilities are endless!