1superhero t-shirt(Instructions above for making your own)
2yardspolar fleece(Red for Superman, Blue for vintage Batman) For a large child or adult, you may need more fabric. For a small child, you can probably get away with less.
1yellow belt(You can make your own from yellow cloth.)
1pairtights or leggings(Royal blue for Superman or gray for Batman)
Instructions
Make the cape
Measure out the width of the shoulders of the person who will be wearing the costume and the distance between their shoulders and their knees.
Cut out a trapezoid shape of the polar fleece with a height equal to the the distance between the shoulders and the knees (or desired length of the cape). The top width should equal the width of the shoulders plus a few (4-6) inches and the bottom width should be that width plus a few more inches (4-6 inches more).
Gather the top of the cape. This can be done by making pleats, sewing a running stick across the top and pulling on the free end to gather the fabric, or by sewing it over elastic while pulling on it. You want to end up with a width that is similar to the width of the shoulders of the person who will be wearing the cape.
If making a Batman cape, fold the cape down the center lengthwise (to make symmetrical cuts) and cut scallops into the bottom of the cape.
Attach the cape to the shirt with pins or by hand sewing it on.
To Make the Boots
Follow the tutorial for making superhero boots out of polar fleece. (Linked to in notes)
To Make the Fingerless Gloves
Cut 2 rectangles out of the polar fleece. The height should equal the desired length of the gloves. The width should equal the distance needed to wrap the fabric around the arms of the person who will be wearing them.
Fold the rectangles in half lengthwise (right sides facing).
Sew down the long open ends of the rectangles.
Turn the tubes right side out.
Try the gloves on and mark the area between the thumbs and the rest of the fingers.
Hand-sew a few stitches at that point to separate the thumb section of the glove from the section for the rest of the fingers.
Make the Trunks
Using a pair of underwear as a pattern, draw out the shape of the trunks onto the polar fleece (using chalk or a fabric marking pencil). Draw the shape 1-2 cm larger than the underwear all the way around them, except for at the waist area. At the waist, make the trunks 2-3 inches taller than the underwear. (This is to leave room for a belt.)
Cut out 2 identical pieces of the marked design.
Place the two pieces together with the right sides facing each other.Sew down both sides and across the bottom (crotch area).
Turn the trunks right side out.
Cut 2 slits for the belt on each side of the waist. Run a yellow belt through the slits.
Make the optional Batman mask
Use a ski-type hat as a pattern for the main shape of the mask. Place it on the polar fleece and trace around it. Make it longer than the cap by extending it down a few inches longer than the ski cap. (This is because it will be worn over the eyes.)
Flip the cap right side out and try it on.
Batman's mask has horn-like projections coming up from either side. Draw them on your pattern freehand.
Cut out the drawn pattern twice. You want 2 identical pieces.
Place one piece over the other and sew around all edges except for the bottom.
Mark where the eyes and nose are when the mask is worn.
Cut out holes for the eyes and cut out the bottom of the mask, leaving room for the nose.
Fill the "horns" with fabric scraps so that they will stay up when the mask is worn.
Putting it all together
Put on the tights or leggings and the t-shirt.
Put the trunks on over the tights or leggings. Fasten the belt.
Put the polar fleece gloves on over the sleeves of the long-sleeved shirt. Pull the polar fleece boots on over the leggings.
Put on some athletic shoes and pull the boots down over the shoes to cover them. You can use some double-sided tape to help hold them down in place.
Put on the optional Batman mask.
Go Save the world!
Notes
Polar fleece is strechy yet lightweight making it very forgiving to work with.
If using a short-sleeved t-shirt, consider making polar fleece sleeves that are hand sewn to the bottom of the sleeve vs. making the gloves as shown. (You can make the "tubes" for the arms in the same way and just omit the step of sewing the stitch between the thumb and the area for the fingers.)