How to Re-Varnish Chairs
Varnish is a clear topcoat that dries hard. Unfortunately, it’s more prone to yellowing and cracking than polyurethane is, meaning it must be removed and reapplied. Removing cracked or yellowed varnish takes a bit of elbow grease, but the resulting tough stabilizer lasts for many years if it’s properly cared for.
Cover your work surface with a drop cloth, and place the chairs on top of it. If you can lift the chairs upon a work bench or table, then it is going to be easier on your back to work on them.
Use a screwdriver to remove the upholstered chairs of the chairs, and set them away in a secure location. If the chairs do not come off, wrap them in plastic trash bags held on with painter’s tape to protect the cloth from your refinishing process.
Scrape away any obviously loose, peeling or cracked varnish with a long-bladed scraper. Take care not to gouge the seat with the corners of the scraper.
Wear safety goggles and a painter’s mash, and sand off the old masonry with 180-grit sandpaper. This might take awhile, especially if the seat has any ornate scroll function, but with a power sander of any kind risks damaging the finish underneath the masonry.
Go over the seat with a tack cloth to remove all traces of the sanding dust.
Apply a thin coat of varnish with a paint brush. Work slowly to make sure you’re applying a thin, even coat with no thick borders wherever your brush strokes overlap.
Let the varnish dry in accordance with the directions on the label. This can take 24 hours or even more depending on how humid the day is and what kind of varnish you’ve used.