50gm Polymorph Moldable Plastic
Polymorph is a plastic that melts at around 60 degrees Celsius and becomes mouldable and easily shaped.
All you need to do is pop some of the granules into hot water or heat them with a hair dryer and once they reach 60 degree you can shape them easily with your hands or put it into a mould ready to make complex shapes.
If you make a mistake just put it back into the water and start again.
This stuff really changed the way we tinkered and has been a life saver for our own projects. We've been working on automating curtains opening when the sun comes up and this stuff works wonders to make mounting plates for the geared motors we are using. The alternative would have been costly and ugly brackets that we'd have to bend to fit the shapes.
Documents:
Using polymorph to make brackets, mounts and sheets