Smoothing Unfinished Flooring

• New, unfinished hardwood planks come roughly pre-sanded, but you'll need to smooth the natural grain further before applying wood stain. For this sanding, you can use a walk-behind random orbital sander or a handheld sander.
  
  A walk-behind random orbital sander features a large sanding disk that spins at high speed. In addition to the spinning, the head of the sander revolves rapidly, which decreases the risk of cross-grain sanding marks on the floor.
  
  You can also complete this sanding step with a handheld orbital or vibrating sander, but wear cushioning kneepads. Both of these handheld sanders do a good job, as long as you move the sander only in the direction of the flooring wood grain.
  
  If you choose the walk-behind sander, you can still use one of the handheld models for sanding at the edge of the floor and in the corners, where the large sander can't reach.
  
  

Stripping Off Old Floor Finish

• Refinishing old hardwood can breathe new life back into your floor. Old finish can dull or wear away after a few years, but you can sand away the surface layer and add new wood stain and wood finish.
  
  If the varnish or lacquer is thin, you can use a walk-behind random orbital sander to strip away the old finish. However, if the old finish is hard and thick, an upright drum sander might be a better choice. The drum sander features a large cylinder, covered with a wide sanding belt. When powered on, the drum sander quickly grinds away the old finish. You will pull the drum sander instead of pushing it.
  
  Use extreme caution when operating a drum sander. This type of sander can dig a depression in the flooring planks within a few seconds if you don't keep the sander moving constantly.
  
  

Sanding for Raised Grain

• Some wood finishing processes, like the application of wood stain or sanding sealer, go on wet and can cause the wood grain to swell. This creates surface roughness that you should sand before you proceed to the next finishing step. A small handheld vibrating sander is effective when fitted with a fine sanding paper, such as 180-grit. You may also sand with a foam sanding pad or plain sandpaper.
  
  

Finish Sanding

• The last type of sanding you'll do on your floor is finish sanding. This involves the buffing away of dust particles that settle on the surface of damp wood finish. No power sanding for this step. Use only a microgrit foam-sanding block or very fine, 400-microgrit sandpaper and use ultra-light pressure. The microgrit will not remove the finish coat, but it will polish the surface, removing the dust particles that can detract from your floor's finished sheen. Finish sand before you add each coat of wood finish.