The traditional way to acquire a mirror finish on hardwood is to utilize a technique known as French polish, which basically consists of rubbing layers of shellac. This technique is time-consuming, though, and due to the stickiness of shellac, it can be tricky. A less demanding method is to rub a previously hardened finish, such as varnish or lacquer. Lacquer is a noncuring finish more akin to shellac than overcast, and because it dries quickly, it is possible to layer it more readily than varnish, which makes it a lot easier to get a glassy-smooth finish.
Sand the bare wood as needed to smooth it and remove the old finish. Complete the sanding procedure by hand-sanding with 150-grit aluminum oxide sandpaper, with the grain of this timber. Wipe off sanding dust with a dry cloth.
Fill the grain with an oil-or water-based wood grain filler. This measure is much more important if the timber is an open-grained selection, such as oak, but it makes it a lot easier to reach a mirror finish on all kinds. Use the filler having a paintbrush, scrape it flat with a plastic paint scraper, and let it dry for several hours. Sand it flat with 220-grit sandpaper, with the grain of this timber.
Spray one coat of lacquer. You may also brush or spray a coat of vanish. Wait for it to dry tack-free; lacquer takes approximately 20 minutes, whilst varnish may take one or two hours. Sand the lacquer or varnish with 320-grit sandpaper and wipe off the sanding dust.
Apply one more coat of varnish. If you’re spraying lacquer, apply two layers, sanding the first one before applying another.
Permit the varnish or lacquer to dry for one day, then level-sand with 400-grit sandpaper to remove bruises and bumps. This offers you a smooth substrate for the finish coats.
Apply one more wet coat of varnish. If you’re using lacquer, employ three additional coats, sanding each with 400-grit sandpaper prior to implement the following. Give the completes time to fully heal before rubbing them. Lacquer takes approximately a week, whilst varnish takes two weeks.
Wet-sand the surface with silicon carbide sandpaper, using water as a lubricant. Start with 400-grit paper to knock down gross imperfections, then sand the whole surface with 600-grit sandpaper. Rub until the surface shows a uniform dull sheen. Repeat the process with 800-, 1000- and 1200-grit sandpaper.
Scatter 4F pumice on the timber, spray some water or rubbing oil on it, and buff up the finish with a cotton cloth. It is a lot easier to find a full gloss finish with a power buffer than it is if you’re hand-buffing.