I used a quality marine spar varnish. After sanding the boards with 120 grit sandpaper, apply a coat of 50 % varnish and 50% thinner. Let dry,
and sand with 280 grit sandpaper,and wipe with a tack cloth. Apply a second coat of 50/50 thinned varnish. When completly dry resand with 280 grit sandpaper and wipe with a tack cloth. Apply a third coat of of 75/25 varnish to thinner. After dry, sand and wipe. For the fourth coat, use a fresh can of varnish(do not thin) and a fresh, clean brush, Do not shake or stir the varnish. To prevent bubbles,wipe of the brush as needed on an empty coffee can. On the last coat, apply to the edges, ends and backside,and allow to dry before applying the final coat to the face side.
