Yep one of my favorite songs and scenes.

I like it when the girl turned blue(berry).

was there ever a pictorial on how he built those mouths with leather?

Just a thought... Been flicking through a few threads. On some joints but mainly the mouth to add flexibility I find the plastic rings from holding beer cans together REALLY reliable.

top picture - http://emusingthings.com/2012/04/05/dangerous-disposable-devices/

Callum.... Makes a lot of sense.... how do you actually use them.  I can kind of understand since they seem impossible to tear apart when I do have to throw them in the trash. Better that they be used on a puppet then end up tangled in sea life.

The way I was shown how to make a mouth piece was two separate pieces of card... with tat in-between. then coated in Denim, then with rest of jeans I use either to belt loops or the hard seam pieces for the finger loops.

I get they are used as the hinge.  Yes very clever.

Wait ... what? I want to learn more about plastic pop can holders. I think I've got the general idea but lacking some details. SO - plastic rings go between layers of denim and plastic/card/etc. This serves as a mouthplate hinge, right? And the rest of the jeans can be used for finger tubes/holders?

I recently dismantled an old puppet I purchased.  The mouth board was... vinyl floor tile! The kind you peel the back off of and stick down.  Not sure it is what I would use (I prefer Sintra or a similar plastic), but it worked. The mouth plate was also sewn to the mouth fabric.  All I can figure is they must have used an industrial sewing machine and an ultra heavy duty needle to get through that stuff. Anyone ever used this material or have tips for sewing through something like that?

Wow... floor tiles! Guess it could work but in my experience, they tend to crack really easy. Not talking in puppet use but when I've used them for floors.   A good home machine and number 16 needle could very well get through them ok I would think. You would want a universal or chisel point. I've sewn through similar thicknesses of other odd materials before with that set up. The only thing is I would not go with the self adhesive tiles if you want to try this. Just like that sticky back Velcro, the adhesive is going to gum up your needle in about an inch of sewing and you'll be sorry!