Propellant
KNDX
KNDX stands for potassium nitrate-dextrose, and is a easy-to-make rocket propellant that is popular with hobbyist rocketry. The most common ratio is 60% potassium nitrate, 40% dextrose (by weight).
Melting
Not melted.
Half melted.
Fully melted.
The End Result
The propellant grains in this image have been made rather poorly, notice the cracks and uneven surface!