A sanding stick helps smooth plastic parts after you cut them from the runner. Even with a good nipper, a small nub or rough mark can remain where the part was attached. Sanding removes that mark and gives the part a cleaner finish.
Sanding sticks are easier to control than loose sandpaper because they have a firm shape. This makes them useful for flat armour panels, edges and small areas. Different grits do different jobs: rougher grits remove material faster, while finer grits smooth and polish the surface.
For Gunpla builders, sanding is especially useful on visible parts. Nub marks can stand out on dark plastic, glossy plastic or clean armour pieces. A little sanding can make the finished model look much neater.
Sanding is also helpful if you plan to paint, because paint usually looks better on a smooth surface. You do not need a huge tool setup to begin. A few sanding sticks in different grits are enough for most starter builds.
Once you get used to sanding, it becomes a simple part of the building process. Kidultverse stocks sanding sticks and modelling tools for customers who want cleaner parts and better-looking finished kits.