When reclaimed wood is cut, sanded or reshaped, the new surfaces lose the original patina. If the look and texture of the untouched material is desired, try distressing and weathering, using only natural materials and methods.
Add scratches and nicks in the wood with a chisel tip, scratch awl and even a chain beaten against the board. Again, study the appearance and patterns of distress in wood and do a test piece before proceeding.
Chemical weathering occurs over years of exposure to water, chemicals from the atmosphere, heat and UV light from the sun. Over time, colors fade and oils are pulled from the wood. Depending on the age of material, chances are the weathered surface is less than 1/4" deep. If the material is trimmed, cut or sanded it will lose its precious patina.
To add an ashy or gray hue (to mimic sun fading), fill a spray bottle halfway with white vinegar. Then shred one pad of steel wool and push it into the spray bottle. Let the bottle sit in a warm sunny area for at least 3 to 4 hours and then spray its contents onto the wood and allow to dry. Age, species, surface cut and sap content of wood will affect the process, so experiment with the amount of steel wool in the bottle, the amount of time the solution soaks and the number of coats applied. Always do a test piece first and stop applying solution when the wood achieves a color that is slightly lighter than the desired hue; the aging process will continue for a short while after drying.
To create a darker gray hue (think wood exposed to harsh elements and/or water), first spray the material with black tea, then follow the steps for a light gray hue. Black tea will add tannins to the open grains and react further with the steel wool and vinegar solution.
When different portions of a piece of wood are exposed to different conditions or materials, variations in patina and color occur. To re-create the look, mask off select areas and/or darken random areas by applying the previously mentioned solutions with a sponge. Wood with nails will also exhibit a blackening around the metal as it has already provided iron to the surrounding wood.
A final finish can accentuate the look of a newly distressed or weathered treatment. For example, wear distressing usually also came with years of use, hands and dirty shoes. This buildup of natural oils and dirt makes its way into the grain of the wood and causes joints, nicks and scratches to stand out even more. This can be re-created by first applying a light paste wax (or other non-hardening finish) to the bulk of the surface. Then specifically work a dark paste wax into the nicks, gouges or holes to darken them. Because the light wax serves as a base layer for the wood, you can wipe off the dark wax from flat areas as needed.