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Achieving A Natural Wood Finish, Whilst Protecting Timber From The Elements

I want my timber to have a natural wood finish; but protected from the elements.

A natural wood finish is often desirable, when you require surface texture on the wood to maintain grip for decks for instance, or a natural wood finish look to garden furniture. Rotting of the wood will occur rapidly in unprotected timber however, so a finish is required that protects without showing.

It may be necessary to restore deteriorated decking or garden furniture, but at the same time maintain the natural wood finish appearance of the timber, to give that rustic look. A boat deck or decking will be too slippery if finished with Smiths CPES™ and then varnish, and a more grippy surface texture can be obtained by following the instructions below.

natural wood finish

Normal Use of CPES protects wood, but needs UV protection

If Clear Penetrating Epoxy Sealer (CPES) were applied to a surface in the usual manner, see full instructions here, a thin film of the cured epoxy resin system would be left on the surface. This would not leave you with natural finish wood. Further as CPES is prone to attack by the ultraviolet in sunlight, as all commercially available epoxy systems are, this residual film can yellow and flake off in the months to come. Such a breakdown of the surface resin film will give an unnatural appearance and jeopardize the life expectancy of a stain the owner might wish to apply.

Protecting the wood and leaving a natural wood finish

The desired natural wood finish, with the original surface texture, may be obtained by a different application of Smiths Clear Penetrating Epoxy Sealer™ (CPES).

Clear Penetrating Epoxy Sealer

This procedure will still protect the wood from rot, making it very water resistant. Smiths CPES penetrates deeply into the surface of the timber, providing a microporous breathable surface to the timber. This means that the wood does not get damp enough for rot to begin, and provides the protection required by wood to last outdoors. The Smiths CPES is mixed and applied to the surface of the wood as normal, applying enough coats that the wood stops absorbing more. these coats are applied over a period of a few hours typically.

A few hours after application of the CPES to saturate the wood, most of the solvents have evaporated, but the resin film on the surface has not yet cured. The resin system is a very special one, in that it cures very slowly. It is therefore possible to dissolve and clean up that surface resin film by wiping it with a rag or paper towel soaked with our Epoxy Cleanup Solvent. When the application is out of direct sunlight the resin system will be scarcely cured at all, even several hours later. The resin that has impregnated the porosity of the surface will not be dissolved in the brief time the surface is exposed to the solvent and wiped clean.
Epoxy Cleanup Solvent is a solvent blend that efficiently dissolves the resins that are used in CPES. Mineral spirits or turpentine will not work, and acetone or MEK evaporate too rapidly to be useful in this sort of application.

How Natural is The Wood Finish After CPES Protection?

The following photographs are of a section of reclaimed red cedar. This is to be commissioned as a staircase and of course is far to soft for there to be any long term durability to the treads.

Two thirds of the top surface of the cedar was treated with 4 coats of Smiths CPES, over a period of about 5 hours. This saturated the surface – leaving it with a shiny finish as expected of saturated timber. This porous timber consumed between 0.5 and 0.75 Litre / sq metre to saturate it fully.

A portion of this was then wiped with Smiths Epoxy Clean Up Solvent to remove the shine and leave a natural finish. This can clearly be seen and compared to the completely untreated timber next to it.

cpes treated cedar wood sample with natural wood surface achieved

The areas treated are marked below.

cedar sample treated with SMITHS CPES then treated to acheve a natural finish

An edge shot indicates penetration of the Smiths CPES through the cedar.

Smiths CPES penetration through timber sample

How good can this protected natural wood look?

Better than you may expect is the simple answer. The oak shaker doors below were finished, inside and out, in under two hours.

You can read more about protecting interior timber from stains and water here.

protected interior timber oak shaker doors

I want to stain and protect my wood, whilst keeping it with a matt natural wood finish

A stain may be applied a few days later. Oil-based stains with a mineral spirits solvent system will be compatible sooner than a waterborne stain, which may require some additional days drying time for the wood. Normally wood is stained before the CPES and a clear finish are applied. That is because stains need to bond to the wood surface fibers, and look unnatural when applied to wood with an epoxy film on the surface. Once the wood surface has been cleaned of the epoxy film as described above, then a stain may be applied as the final finish if desired.

Copyright Steve Smith and Stephen Dakin 1993 – 2017, All rights reserved