How to Create the Perfect Epoxy Coating Over Wood

WEST SYSTEM® Epoxy is an invaluable resource for creating a clear coating that highlights the natural beauty of wood grain while providing four times the thickness of a single coat of polyurethane. In just a few simple steps, you can achieve a beautiful, bubble-free wooden surface using epoxy resin.

Bubbles are a frustrating side effect of epoxy coating that can make your clear-coated wood finish appear unattractive and rough. Therefore, it is important to remove all air bubbles before the epoxy gels, as trapped bubbles can create imperfections or pop and form sharp ridges.

Preparing the Surface

To achieve a clear coating, it is crucial to prepare the surface thoroughly. The surface should be clean, dry, and free from any contamination. Sand the surface and vacuum any residual dust to prevent bubbles, blisters, or other imperfections in the coating. Any contamination on the surface can cause the coating to bead up, a phenomenon known as reticulation, which results in dry spots.

For superior clear coatings, sanding with the grain enhances the aesthetics of the finished product. Naturally, oily woods such as teak should be cleaned with acetone and paper towels to remove surface oiliness.

The working environment plays a significant role in the quality of the finished coating. A dry, dust-free space will yield the best results. Additionally, the temperature of the workspace, the wood, and the epoxy should all be similar, ideally around 65°F (18°C).

Applying cold epoxy to a warm wood surface can cause air in the wood fibers to expand, leading to a phenomenon known as “outgassing.” This can result in trapped air bubbles, cratering, and pitting. Cold epoxy is also more difficult to spread evenly and may be applied too thickly, leading to an uneven finish.

Applying the Epoxy Coating

Once the surface is fully prepared, you can begin applying the epoxy. It is advisable to apply multiple thin coats rather than a single thick coat. The best results are achieved by applying the epoxy evenly using the “roll on and tip off” method—roll on a thin layer of epoxy with a foam roller and then “tip off” by dragging another roller (cut into sections) across the surface to level it and remove air bubbles. The WEST SYSTEM® 800 (7″) yellow roller sleeves are excellent for this application.

With coarse-grain timbers, the first coat may lift some wood fibers, creating a rough surface. If this occurs, allow the coating to cure, then sand the surface smooth before applying the next coat.

Once the epoxy is as tacky as masking tape, apply the next coat. If you cannot make a fingernail impression in the coating, wait until it has fully cured, then wash off any amine blush before sanding and applying the next layer. While the epoxy cures, gently apply a dry heat source, such as a hot air blower or propane torch (used with extreme care), to remove any air bubbles. Warming the epoxy reduces viscosity, making it easier for trapped air to escape.

For the Best Results:

• Prepare surfaces meticulously – Ensure your surface is dry, free of dust and contaminants, and thoroughly sanded.
• Use WEST SYSTEM® 207 Special Coating Hardener – This hardener cures with minimal blush in optimal conditions. The mixed epoxy flows smoothly, making it ideal for clear coating.
• Apply multiple thin coats – Use a foam roller and tip off after each application. You will typically need 2-4 coats, applied when the previous coat is tacky.
• Protect outdoor surfaces with a UV-resistant clear coat – While WEST SYSTEM® 207 Special Coating Hardener contains UV inhibitors, an additional UV-resistant topcoat is necessary to protect the epoxy from sunlight degradation.

By following these steps, you can achieve a smooth, aesthetically pleasing clear coating that is both bubble- and blister-free.