Category Archives: Coating

Applying Epoxy on Vertical Surfaces

By Greg Bull — GBI Technical Advisor

Why can’t I apply epoxy to vertical surfaces? This is a question Gougeon Technical Advisors are asked all the time. Our response? Why, sure you can! You just need to apply it in thin coats using a foam roller. I’ll provide some tips for preventing sags or runs when coating vertical surfaces, achieving a thin coat, and choosing the best hardener for your working temperature.

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Several small parts coating by Russell Brown

Coating Small Parts

By Russell Brown — Port Townsend Watercraft

Pre-finishing parts with WEST SYSTEM® Epoxy before installation is a technique that was popularized by guess who? The Gougeon brothers. It can save time and increase the quality of the finish. Coating small parts can also be a challenge, but it’s much easier if the parts are held in a way that provides good access for roller and brush coating. Continue reading

Water beading on a bright finish topcoat.

The Art of Choosing a Topcoat

By Rachael Geerts – GBI Composites Materials Engineer

You’ve just finished your epoxy project and it looks great! But you don’t want the sun’s UV rays to start degrading the epoxy. So, like the smart individual you are, you look into applying a UV stable topcoat over the epoxy so your project will last for years to come. You look at your options, go down a few rabbit holes, and come out much later asking why is it so difficult to select a UV stable topcoat for my epoxy project? Continue reading

varnish over epoxy

Clear Coating with 207 Special Clear Hardener

By Terry Monville — GBI Technical Advisor

Not that long ago, clear coating with epoxy meant that you were finishing a natural wood canoe or kayak, or the teak toe rails on your boat. Today, WEST SYSTEM 105 Resin and 207 Special Clear Hardener is used for clear coating in many different ways. Regardless of the project, there are some basic techniques to follow when epoxy coating and a few pitfalls to avoid. Continue reading

Tom's canoe hanging in the tech shop

Refinishing a Wood Strip Canoe

By Tom Pawlak — GBI Technical Advisor

About 30 years ago, I built an 18′ wood strip canoe. At the time, my family was young and I could only work on it intermittently. Over the course of six months, I had faired my mold frames, applied the redwood strips, faired the outside of the hull with a keen eye and applied the fiberglass cloth. Two months later I decided to take it off the mold to fair and fiberglass the inside. To my horror, the exterior hull bottom had a big dimple in the middle when removed from the forms. I immediately knew the cause. The humidity in my garage had skyrocketed since the outside of the hull was finished with fiberglass and epoxy. The unsealed inside of the hull had probably gained 4-5% in moisture content since the outside was fiberglassed. Continue reading

rudder and dagger board

Sunfish Wood Restoration

By Don Gutzmer – GBI Technical Advisor

During the fall of 2016, I took a technical call from a customer who owned a Sunfish Sailboat. He lived in the area and was looking for help repairing a few minor gel coat cracks and restoring his wooden daggerboard and rudder. I told him I would be happy to help because this would be a good opportunity to write an article about using WEST SYSTEM 105 Resin and 207 Special Clear Hardener for the wood restoration part of his project. The mahogany daggerboard and rudder had weathered over the years because of only being varnished. Continue reading

Sparks is a great example of good sealing and priming.

Sealing and Priming

Lesson 4 in our series on Strip Planking

By Ted Moores

Sealing and priming a surface prior to applying the final finish affects how it ages, and how it ages has everything to do with the way the finish is anchored to the wood. Sealers and primers are often taken for granted; we simply read the can and follow directions. There are so many reasons for using a sealer and many methods for applying them. Let’s look at what we learned while sealing Sparks, the electric launch I built. Continue reading

Bubble-Free Epoxy Coating

By Mike BarnardDon Gutzmer

WEST SYSTEM® Epoxy has long been a popular choice for clear coating tabletops, and for these applications, you’ll want a bubble-free epoxy coating. Epoxy works great as a buildup coat and a moisture barrier. It also showcases the beauty of wood grain and fiber weaves. Formulated with boat building in mind, WEST SYSTEM Epoxy is not intended as a final finish coating. You may find it a bit more difficult to achieve a perfect surface with epoxy than with a coating formulated specifically for final finishing, such as varnish. Here’s how to make sure your epoxy coating is bubble-free.

However, WEST SYSTEM offers some distinct advantages. It builds up quickly: a single coat of 105 Epoxy Resin® with 207 Special Clear Hardener® offers about four times the thickness of a typical coat of polyurethane varnish. WEST SYSTEM epoxy is also an excellent moisture barrier, stabilizing the surface so your final finish coat will look beautiful longer.

When coating a surface that will be used outdoors, it’s important to put a UV-resistant clear coating over the epoxy. While 207 Special Clear Hardener contains a good UV inhibitor, it will still need additional UV-resistant coats to withstand the degrading effects of sunlight on epoxy.

Since you will need to sand down the epoxied surface and coat the epoxy with varnish, getting a perfect coating isn’t strictly necessary. But the better shape it’s in, the more easily you will achieve a beautiful, bubble-free finish. The key is creating the smoothest, flattest epoxy surface possible. This will save you a lot of sanding later.

Last summer here at the Gougeon shop, we laminated a 35-year-old conference table with carbon fiber and WEST SYSTEM 105/207. We experimented with different methods of achieving a smooth, even, bubble-free epoxy coat to reduce the need for sanding prior to the final finish coating. (Editor’s note: 10 years after this article was written, that carbon-fiber conference table still looks terrific.)

Prepare the surface

Proper surface preparation is one of the most important steps in using epoxy. Make sure the surface is clean of contaminants such as wax and paint. Sand the surface smooth. Avoid using solvents immediately before applying the epoxy.

Eliminate dust

Getting a perfectly smooth surface starts with clearing the air of small particles. These particles may seem harmless, but once they are on a glossy surface it will not look nearly as good as it could. Avoid using tack rags. Vacuum the surface before coating.

Understand outgassing

Before coating bare wood, heat the wood and apply the epoxy while the wood is cooling. During cooling, the air in the wood contracts, drawing the epoxy in for a bubble-free epoxy coating. The opposite happens if you coat wood as it’s warming (such as in the morning, in the sunlight, near a heater or anytime ambient temperature is rising). The air in the wood will expand and “outgas” while the wood’s temperature is rising, resulting in bubbles in the curing epoxy coating.

Applying over stains

Be careful when using WEST SYSTEM Epoxy over commercial stains. Some stains prevent epoxy from penetrating into the wood. The result can be epoxy that fisheyes or peels off after final cure. Always perform a test before using epoxy over a stain.

Avoiding blush

It’s easy to avoid the inert, waxy residue that is sometimes a byproduct of the curing process and is commonly called “blush.” Simply use WEST SYSTEM 207 Special Clear Hardener. It cures blush-free. It’s also formulated for excellent wet out and self-leveling. It cures extremely clear and without color.

If you are using WEST SYSTEM 205 Fast, 206 Slow, or 209 Extra Slow Hardener, blush might develop on the surface, depending on working conditions. It’s easily removed after the epoxy cures with plain water and a light scrubbing with a Scotch-Brite™ pad. These hardeners are not normally recommended for clear coating.

Rolling and tipping

The only recommended way to coat vertical surfaces with epoxy is the roll and tip method. Roll the epoxy on with a foam roller, then “tip” by dragging another roller across the surface to smooth the epoxy layer.

Tip off wet epoxy with a roller cover brush using long, even overlapping strokes. This will leave a bubble-free epoxy coating.

Tip off wet epoxy with a roller cover brush using long, even overlapping strokes. This will leave a bubble-free epoxy coating.

Flow coating

This is the best method for encapsulating items in a bubble-free epoxy coating. The fewest bubbles result if epoxy is poured from the bottom of a container. A word of caution: Never pour a single layer of epoxy thicker than ¼”. Thicker amounts can quickly overheat or “exotherm” during cure, resulting in quite a mess on your lovely surface. If you want a final thickness greater than ¼”, wait until the first layer is cured to the point where it’s firm and about as “tacky” as masking tape then apply the next coat on top of that.

If encapsulating items such as coins, medals, bottle caps and photos on a flat surface, affix them in place with decoupage glue such as Mod Podge® (readily available at craft stores). It’s compatible with epoxy and will prevent your items from floating around. Use it to pre-seal photos and other paper items.

Propane torch

This method of achieving a bubble-free epoxy finish has been used for years by technical advisors at Gougeon Brothers. Not only is it effective for removing air bubbles from the surface, it also lowers the viscosity of the surface and flattens it out a bit. Be very careful when using this technique because leaving the flame over one spot for too long could cause bubbles to appear. We don’t recommend using a propane torch over epoxy-coated bare wood. Doing so may cause outgassing into the epoxy layer.

A thick coating of epoxy with bubbles in the coating.

A thick coating of epoxy with bubbles in the coating.

Pass a torch flame quickly over wet epoxy to warm the surface, reduce the surface tension, reduce viscosity slightly and release air bubbles, resulting in a bubble-free epoxy finish.

Pass a torch flame quickly over wet epoxy to warm the surface, reduce the surface tension, reduce viscosity slightly and release air bubbles, resulting in a bubble-free epoxy finish.

After a quick pass with a torch, the bubbles are released and the coating begins to flow out.

After a quick pass with a torch, the bubbles are released and the coating begins to flow out.

Denatured Alcohol

Spraying a fine mist of denatured alcohol over the surface will pop air bubbles as well as lower the viscosity of the surface and flatten it out. There is little risk in this method because denatured alcohol evaporates fairly quickly and does not cause air bubbles to propagate. A fine mist is critical. To get the fine mist we purchased a bottle of hair spray with a push button pump (a Windex™ sprayer is not fine enough) and replaced the hair spray with denatured alcohol.

A fine mist of denatured alcohol will reduce surface tension and release air bubbles, resulting in a bubble-free epoxy coating.

A fine mist of denatured alcohol will reduce surface tension and release air bubbles, resulting in a bubble-free epoxy coating.

An S hook will save your foam roller frame.

Saving Your 801 Roller Frame

by Captain James R. Watson

Photo at top: How a simple S hook can save your 801 Roller Frame.

When you’ve completed a coating task using an 801 Roller Frame and 800 Roller Cover, what next? The frame is reusable. But if you leave it resting in the pan while the residual epoxy cures, you‘ll probably ruin both the reusable pan and the frame. If you lay the roller and frame on a workbench, it will be stuck there the next day. Here is a simple solution to this problem that will allow you to reuse your frame again and again.

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