Care & Maintenance of Clear Wood Finishes

Clear finishes are usually specified for window and door applications in order to retain the natural appearance of the wood used in fabrication of Woodstone's windows and doors. Natural appearances vary from a high gloss finish to a semi gloss finish to a natural weathered appearance. When products leave Woodstone's shop, the clear finish is typically applied to freshly milled lumber. Freshly milled lumber demonstrates wood grain coloration that has not been oxidized by sunlight (usually darkened, i.e. mahogany & cherry) or weathered gray by rain or water splash. The natural weathered appearance of wood grain is therefore dependent upon the wood species, the extent of exposure to the natural elements, the number of coats of finish applied before the weathering process begins and the frequency of refinishing. Weathered wood can usually be restored to its original appearance by sanding the weathered surface, exposing fresh wood grain and applying the appropriate number of refinish coats.

Extreme weathering can result in open grain wood checks that allow dirt and bacteria deep into the wood causing typically black discoloration. This discoloration is especially typical at egress door sills and is virtually impossible to remove without professional services using bleach and other chemical solvents to penetrate into the open grain of the wood.

White Oak and Mahogany are typical open grained hardwood species that demonstrate a high resistance to decay but are prone to deep discoloration when allowed to weather. Cherry, on the other hand, also has a high resistance to decay but is a much tighter grained wood species and is not as prone to open grain. However, Cherry is not as hard as White Oak or Mahogany and will wear more in egress sill conditions. Cherry and Mahogany are prone to accelerated oxidation (darkening) by direct sunlight. For example, freshly milled Cherry and Mahogany will show visible darkening in minutes when exposed to direct sunlight.

Pines and Cedars are also typically used to fabricate windows and doors. However, Pines and Cedars are softwoods and typically not used when a clear fresh wood appearance is required. Only hardwoods are used for egress door sills.

Woodstone recommends clear finishes with Tung Oil as the primary ingredient including Ultra Violet Light (UV) inhibitors to protect the finish from breaking down in sunlight. Currently Woodstone recommends and uses Waterlox Marine Finish for units specified with clear finishes.
(continued on reverse side)

Clearly, there can be no set rule of thumb established for the maintenance of a given appearance.

Typically, Woodstone recommends at least one coat of Waterlox Marine Sealer followed by two subsequent coats of Waterlox Marine Finish applied during the fabrication process. Woodstone applies the first coat of Marine Sealer and the first coat of Marine Finish before the window and door units are fully assembled. This practice insures that all sides and ends of each wooden component receive a coat of finish protection. Subsequent coats should be applied as frequently as required to produce and maintain the natural appearance desired.

For high gloss finishes intended to maintain as closely as possible the appearance of freshly milled lumber, the more coats applied the better. For example, wooden yacht manufacturers often recommend as many as 8 or 9 coats of finish initially followed by 2 or more refinish applications per year. Windows and doors that are exposed to extreme water and sunlight conditions require more finish than those installed in protected areas. Sills typically require more maintenance than other parts of a window or door, especially door sills that are subject to egress conditions.

If natural weathering is not an issue, Woodstone's typical factory application of one coat Marine Sealer with two coats of Marine Finish is sufficient to protect the integrity of the window or door assembly and function for at least one year. Some movement in the wooden components may occur. But the wood joinery and operating function should not be compromised.

Again, there can be no set rule of thumb established for the maintenance of a given appearance.

The advantage to Waterlox Marine Finishes and other Tung Oil derivatives is the flexible nature of the product. Unlike urethane, Waterlox Marine can be spot refinished. Light sanding to exposed areas with the application of additional coats of finish can be blended into the existing finish without having to strip the entire unit. In extreme conditions compatible oil based stains can be added directly to the Waterlox Marine Finish to achieve the desired coloration.

The attached Waterlox Product Bulletins are enclosed for your consideration. If you have any questions, please don't hesitate to contact Waterlox or Woodstone's Customer Service Department. For more information on finishes, please refer to Woodstone's Installation Procedures, Paint Service and Prime Paint Service documents.

Filename: product\finishes\clear1
Last Update: 7/12/96 HJE