Why is my wood not smooth after sanding?

Why is my wood not smooth after sanding? Even after sanding, many of these woods will feel fuzzy or slightly rough after the first coat of paint or varnish has been applied. This is because the coating wets the grain and causes the fibers to swell slightly, ruining what seemed to be a perfectly smooth finish before you started.

Even after sanding, many of these woods will feel fuzzy or slightly rough after the first coat of paint or varnish has been applied. This is because the coating wets the grain and causes the fibers to swell slightly, ruining what seemed to be a perfectly smooth finish before you started.