Epoxy Putty is an amazing product.
It's Play-doh that hardens up in 5 minutes and sticks hard to whatever you glom it on to.
Need a replacement for a broken plastic part? Make a mold from the broken part in RTV silicone, then use steel filled epoxy to make a replacement part.
It's in the Glue section. Next time we'll be covering using canvas and Great Stuff expanding foam to make a waterproof tent.