With Halloween approaching, I decided to make him a WW2 Captain America costume similar to the one in Marvel's "Ultimates" timeline.
As you can see, it worked out well. Now we have our own little super soldier watching over our neighborhood.
Step 1: Materials
I still had to buy new items like: the shield (Amazon), a pair of red gloves (welovecolors.com), a toy army helmet, red and navy dye, blue and white spray paint (Walmart), a can of spray foam insulation, a tube of gorilla glue, and a can of red plast-dip (Home Depot).
Step 2: The mask
Pressing the mask's seams was a bear (particularly the eye-holes). And in the end, I had to resort to hot-gluing the seams to the underside of the mask. This was the only way I could keep them from poking into my son's eyes.
I decided to dye the mask (and enough white cloth to make the nessesary jacket stripes and boot anklets) outside, so there'd be less mess. However, I discovered that room-temperature dying doesn't produce colors as intense as stove-top dying.
After the dye-job, I finished off the mask with a chinstrap made from a piece of brown vinyl leftover from a previous project.