Most people hate sanding. Power sanders are noisy. They blow dust everywhere. Hand sanding is tiresome. It’s slow. So do-it-yourselfers search for alternatives (and the main alternative these days appears to be chalk paint…).
I don’t use a power sander for the two reasons above. I sand by hand. I sand to help remove old finishes, to smooth out blemishes, to smooth out repairs, and to remove the little touch of roughness between all coats of paint and all coats of varathane. My finished product is smooth and gleaming. I don’t think sanding takes a huge amount of time unless you’re in a huge hurry. And I am not.
A combination of paint stripper and coarse sanding removes old finishes – paint, varnish, general grime. Sometimes it takes a bit of elbow grease to get everything cleaned off, but it means I start the renewing process with a clean slate, plus the surface is roughened for better adhesion of new finishes. Sanding may even expose a defect that wasn’t obvious before. I also use it to take the sharpness off edges, rounding them out a wee bit to make them smooth and less scratchy.
Sanding may be all that’s necessary to remove flaws or little nicks in wood. It assists in preventing sap or stain bleed-through (though it can’t do it alone), and it smooths out modifications when applying wood filler – as this filler step moves along, I move from coarse to fine sandpaper, matching the surface to undamaged areas.
Priming and Painting
When primer or paint is applied over raw wood, and to a lesser degree over surfaces just painted, it raises fibres sheared by previous sanding now standing randomly on end (this is known as “raising the grain”). Smoothness is restored by removing these bits.
Light sanding after each coat removes flecks transferred to the surface by brush or paint. It can correct small mistakes like drips or brush strokes, though it depends upon the depth of the error. It’s even useful between coats of varathane to remove specks and smooth the surface more.
A Final Note of Caution
ALL SANDING LEAVES A FINE, SOMETIMES UNNOTICEABLE, LAYER OF DUST. Therefore, every time it’s completed, the surface should be vacuumed and lightly wiped with a damp or tack (wax impregnated) cloth.
If you take the time to do all of this, the end result will dramatically improve. It is SO worth the effort.