Revealing mistake: After the toy car crashes, the group falls down a hole, but their clothes don't react to gravity, revealing the green screen trick.
Revealing mistake: When the group is riding the toy car, in the wide shots of a real toy car, they disappear.
Answer: Epoxy resin is sometimes sold in two seperate tubes. You have to mix the contents of both for the epoxy to harden into plastic. It also shows how weird he is, as epoxy tends to smell pretty foul.
Grumpy Scot