They clear and fill the holes, then use a roller or whacker to smooth the surface.

BBC: Jetpatchers at work

It was the tou the wide, well-honed, flat-edged whacker of a knife that Chinese cooks used for everything from butchering to dicing and fine slicing and the chopstick, which, in the Song era, came into common use.

NEWYORKER: A Fork of One��s Own

It is to rein in government spending and to lower taxes, for taking a weed whacker to excessive regulation and mandates, for putting a stop to tort windfalls and to stand up to the tyrannosaurus appetite of government unions!

NPR: Transcript: Mitt Romney At The RNC