Brush a heavy coat of chemical stripper on the surface of the redwood outdoor furniture. Allow it to sit on the furniture until the old finish bubbles and peels.
Remove the old finish by scraping the surface of the furniture with the putty knife. Scrub the stubborn areas of old finish off with steel wool.
Sand off remaining scraps of the old finish with 120-grit sandpaper. Sand the furniture again with 220-grit sandpaper.
Brush a coat of sanding sealer onto the redwood outdoor furniture. Wipe off excess with a cloth and sand again with 220-grit sandpaper.
Wipe even coats of stain onto the furniture with a cloth. Wait for the stain to absorb into the wood and wipe off excess with a cloth. Wipe on more coats to create a darker finish.
Brush a thin, even coat of polyurethane on the redwood. Sand the furniture again with 220-grit sandpaper and brush a second thin coat of polyurethane.