The simplest way to create a weathered finish on painted wood is to break a few of the rules. The standard instructions for wood refinishing are designed to produce a smooth finish that will make the wood look like new. By selectively violating those guidelines you can, instead, raise the wood's grain to give it a subtle, weather-worn texture that evokes the appearance of driftwood. The key is to expose wood to water during the stripping phase of your project.
Off With The Old
Apply NMP paint stripper paste to the wood's surface using a disposable paint brush, and leave on for at least 3 hours. If there are several layers of paint and primer, the paste should be left on the wood overnight.
Scrape off the paint stripping paste using a carbide blade paint scraper. Start by scraping in the direction of the grain, then remove any residue by scraping perpendicular to the grain. This may create small scratches or nicks in the wood.
Rinse off any leftover paint and stripping paste using a hand-trigger spray bottle to thoroughly wet down the wood. Wipe off the excess moisture using a cotton cloth.
Soak a fresh cotton rag with denatured alcohol. Wipe down the wood and allow the alcohol to thoroughly penetrate the surface. Refresh the rag with alcohol as needed.
Spray the wood with water again, then wipe off any excess moisture with a cotton rag and allow the wood to dry completely.
Sand the wood, rubbing 180-grit sandpaper in the direction of the grain to smooth down any rough surfaces.
On With The Not-So-New
Dilute an all-purpose water-based white paint primer with water, using a ratio of 3 parts water to 1 part primer.
Brush the primer mix in the direction of the grain onto a roughly 2-foot-square section of the wood. Using a clean cotton rag, rub the primer into the wood and wipe off any excess. Repeat until the entire surface of the wood has been treated.
Wait 2 hours for the surface to dry.
Sand the wood gently with 180-grit sandpaper to smooth off any roughness. Wipe off any sanding residue using a tack cloth.
Apply a thin coat of flat-sheen water-based varnish using a lint-free cotton rag. After 3 hours, apply a second coat.