You'll be using the oven and a hot glue gun, so please exercise caution when handling hot materials. I seem to enjoy hot-gluing my fingers together, but that's just me.
Step 1: Materials
Here you'll see 1" pin backs, 1/4" jewelry rings (two per ribbon), 1" wide ribbon, hot glue gun, don't forget to check your supply of glue sticks, scissors, clear plastic (more on this later). Not shown: cookie sheet, Spray paint (optional), single hole punch, needle nose pliers, ruler, and a Sharpie pen.
I collect those plastic containers from takeout, restaurants, bakery goods, etc. Don't keep the ones with labels, I've had no luck removing them for shrinky use.
Step 2: The Shrinkie Medal
The 2 1/2" drawing shrunk to about 3/4". I've used 3" as well. Printing words also works well since the shrinking process improves imperfections in tracing.
Trace the drawing using a large sharpie. Turn it as needed to make best use of your piece of plastic.
Cut each one out. Tedious, but remember the money you're saving. Cut on the outside of the dark line if you want this in your medal, I did. You can always add any with the sharpie that get cut off too much in the process.
Careful on inside corners where the scissors can break the plastic as you try to make the turn. I suggest coming into the corner from each side to avoid this possibility.
My trusty single-hole punch, what would I do without it? I leave at least an 1/8" from each edge to avoid the plastic melting away from the hole.
Step 3: Shrinking
I place the cookie sheet in a cold oven and set it for 350 degrees. You can see in the pictures that they will curl up in a 'cupping' fashion. Don't panic, they will flatten out. I've experienced some plastics that don't quite get perfectly flat, but that just makes them uniquely hand-made. Of course for my example, they turned out perfectly. Total time is around 5 minutes; keep an eye on them and take them out when they flatten out.
Slide the wax paper off the cookie sheet onto the counter and move each medal to prevent them from becoming one with the wax paper. Mine cool very rapidly. Be careful!
Step 4: Medal Prep
Using your needle nose pliers, attach a ring to each medal. Don't bend the ring closed just yet; we still want to attach it to the ribbon later.
Step 5: Ribbon Prep
Cut the ribbon 2 1/2" long. Alright, it's a little short in the picture. It'll work fine. Roll the ribbon lengthwise and insert it through a ring stopping not quite half-way.
Flatten out the ribbon and fold the short side up to within 1/4" of the top of the long side. A drop of hot glue will hold this in place and keep the front from pulling away while hanging. Then a bead of glue to fold the 1/4" flap down giving a nice clean top to the ribbon. Another bead of glue on top of the folded flap will be the seat for the pin-back. You can orient the pin for righties or lefties. I'm a rightie so I have the hinge on the right and clasp on the left.