I'm taking an introductory costuming class this semester, and I made this head form in it! It's to practice for making a whole dress form, which we'll be doing soon.
I made it by wrapping a foam head in cling wrap, then ductape. Then you cut it in half so you can take it off the head, and fill each half with expanding insulation foam! Once that's hardened, you cave down the foam til the 2 halves fit together, and ductape it into one!
I'm super proud of it, even if it is a little uncanny valley 😬! I put my latest hat on there to stretch the crochet a bit so it's not too tight on my noggin!
A couple thumb tacks on the side for ears, and it can model masks too!