Natural wood grain patterns are one reason makers opt for using lumber as a building material for projects. The unique designs and textures add an organic, visually appealing element to any creation. However, wood grain texture can also present compositional obstacles—knots and fibers often lead to voids or holes in the wood’s surface.
Wood grain filler is specifically used to fill in these gaps and depressions without diminishing too much of the raw wood’s aesthetic. This treatment solution helps to maintain the integrity of the wood, reinforcing structural weak points but keeping much of the grain pattern intact and visible. Some form of wood filler is crucial if you intend for the surface of your final project to have a high-shine finish (e.g., instruments or fine furniture.)
Wood Grain Filler Basics
Most often, woodworkers use wood grain filler on open-grained types of wood, such as oak or ash. These species normally have relatively large pores that must be filled prior to finishing in order to achieve an even, flat surface. Producing a glassy smooth finish, especially when using an open-grained wood, is nearly impossible without employing some sort of wood grain filler.
Oil-Based vs. Waterborne Fillers
While oil or petroleum-based filler has been the traditional choice for quite some time, waterborne wood filler is an innovation that’s hit the market more recently. The introduction of this solution creates the potential for additional finishing combinations for more specialized applications.
Here are a few general pieces of knowledge regarding the difference between oil- and water-based wood fillers:
- It’s best practice to pair oil-based finishes with oil-based fillers. Ensure all layers are completely dry before applying the next wood treatment.
- Meanwhile, waterborne fillers can typically be paired with either oil-based or water-based finishes.
- Waterborne fillers usually dry more quickly, making them less messy to work with but presenting more of a time crunch for application.
Wood Grain Filler vs. Wood Putty
Generally speaking, wood grain filler uses a non-shrinking binding agent to fill pores, while wood putty is intended to fill large cracks and voids in the wood. Wood putty is exactly that: a malleable, clay-like substance that’s much thicker than a wood filler, which has the consistency of a thin paste.
Wood Grain Filler Application Tips
Apart from having the foundational know-how to employ wood grain filler, it’s also important to have the right tools to accomplish the task. Wood graining tools usually resemble a baker’s dough scraper—a thin, flat manual tool made of durable plastic or metal with a grip on one edge. A grain filler spreader and leveler is a simple but essential tool for properly applying wood grain filler.
Before Application
Be sure to clearly outline the steps necessary for preparing your wood surface, including necessary supplies, techniques, and an idea of what your desired results are. Wood filler is a preliminary step in the wood finishing process—you can’t decide to use it later or change your mind about whether or not it’s necessary for the final look you’re going for. Review the ideal method for prepping wood surfaces to ensure best results.
After Application
It's important not to jump right into the finish application as soon as your wood grain filler is set. Wood surfaces often require additional sanding or treatments before you can apply a final topcoat. Depending on the look you’re going for, you may need to use wood conditioner, primer, or pre-stain solution prior to putting the finishing touches on your project.
Other Things to Note About Wood Grain Fillers
If your waterborne wood grain filler is drying too quickly, you can try re-wetting the filler using a spray bottle or towel, but be aware the solution can start to coagulate if this is done too much. It also may be helpful to work on smaller areas at a time.
Like any wood treatment solution, be sure to follow the manufacturer’s instructions for use. Not all fillers are created equal, and they tend to have different requirements set by their individual manufacturer. For specialized applications, consult with a finishing expert before deciding on a technique.
To Achieve a Fine Finish, Start with the Right Resources
With so many patterns, colors, and types of wood grain on the market, preserving the distinctive appearance of the wood is often a priority for makers. However, leaving open-grained wood exposed is not only a risk to the structure but also makes it nearly impossible to achieve a glassy finish. For an especially durable or high-shine finish, wood grain filler is nothing short of a necessity.
At FinishWorks, providing you with reliable access to the supplies, support, and knowledge necessary to complete your projects is our top priority. Download our guide, Why Your Current Wood Finish Brand Isn’t Cutting It, to learn how to make the most out of your manufacturer relationships and discover what puts FinishWorks a cut above all the rest.
