I love listening to these old effects legends and being a stop motion animator myself it's always a treat to hear people like Phil Tippet talk about how things were done back then.
Here's an old thread I put up on here about when I went to meet him - https://starwarsforum.co.uk/viewtopic.php?f=7&t=13642&p=185662&hilit=phil+tippet#p185662
Ian