I've made a couple of different animal heads for costumes over the past few years and each time I learn a little more! Here's my latest: a bear to do battle with Teddy Roosevelt!
What you'll need:
2x4' of 4" foam (I used upholstery foam)
3/4 yard faux fur
small pieces of accent fabric
2 glass eyes
Step 1: Sketch and gather materials
The first step is to sketch out your design. I roughly drew out my plan and took measurements based on proportions I wanted, although in the end the final product ended up being a little smaller. Use your sketch and rough measurements to figure out how much foam you'll need to purchase. I used 1 piece of 2x2' foam that was 3" thick and 1 piece that was 4" thick because that was what I had on hand - but you can use a variety of foams for the structure. Whenever you're layering up foam be sure to use the correct adhesive for your material as some glues will eat through certain kinds of foam or won't adhere properly. I used the adhesive pictured below and was very happy with the results!
If there are any areas of your mask that stick out - like the nose, ears, horns, etc - plan on constructing those elements separately to help minimize the size of the foam you need to purchase. For example, I carved my bear's muzzle separately and then glued it back onto the head.