Bondo is a paste, then you add a couple of drops of hardener and mix it in. It is pliable enough to work into a simple mold, hardens pretty fast and easy to sand. Magic sculpt is a 2 part epoxy but not available locally, unless you live near a vendor. Portland and Seattle have Tap plastics and they sell it. Aves is also available online. Hardware stores sell a 2 part plumbers putty thats easy to use. The world is your oyster.