Hunter Cummins
Gordons posts explains it well but yea, its a putty and many more things lol

John Van Kooten
Filling holes & gaps or smoothing out irregular surfaces is exactly the one thing I do NOT use Mr. Surfacer for 😉 😄

I use it to create cast iron texture on a turret, for instance. Simply apply it to the surface (with a regular brush) and rework with a brush (or other suitable tool) in a dabbing motion, until the desired textured effect is achieved.

It's a very fine grained and easily workable, thin putty, which allows you to create all sorts of textures. It is, however, not suitable to create zimmerit. For that, it is too thin.

Btw: be very careful when using this stuff because it is laquer based (contains solvents). The hazardous fumes welcome you the moment you unscrew the cap (and it's VERY obvious)!