In the Shop: Aqua Coat clear wood grain filler

Increasing demand for flawless glass smooth finishes on woods with open pores like oaks, ashes, and mahoganies presents a challenge for finishers. My first experience with this came a few decades ago when I started making stringed musical instruments. Achieving the perfect gloss finish was a painstaking and lengthy process using messy paste fillers that sometimes dulled the look of the wood and then moving on to many coats of lacquer.

With that experience behind me, I was ready to try the new Aqua Coat clear wood grain filler. It promised to provide not only an environmentally friendly alternative, but a more efficient one, too.

What it is

Aqua Coat wood grain filler is a water-based gel that is designed to fill wood grain pores so that top coats have less work to do in producing a level finish without the pockmarks of wood pores. The manufacturer markets the filler as the next step after staining and/or sealing to achieve a high gloss finish.

Opening the can, you immediately see some differences between Aqua Coat and more conventional grain fillers. First off, the can itself is a recyclable plastic tub with a metal twist-off lid. That’s much easier to use than the conventional pry-top metal paint cans. The look and smell of the filler is different, too. It’s a lightweight white gel that looks a little like the gel hand cleaners you can buy. There is no strong petroleum odor either.

How it works

Aqua Cote recommends that you apply their filler after staining or sealing. If there is to be no stain, applying over raw wood is acceptable. That’s how we tested the product, since filling the pores in raw wood presents the biggest challenge for grain fillers. Aqua Cote recommends using a rubber squeegee, soft putty knife or a soft cloth to apply the filler, working it into the pores in a circular motion, much like you would apply paste wax. It goes on quick and easy, and then you wait for it to dry 30 to 45 minutes before sanding.

I was impressed that the surface didn’t have that cloudy look that you sometimes get with old-fashioned paste wood fillers. I found two coats were plenty to fill the wood pores, sanding between coats as recommended with 320 grit. You can topcoat after letting it dry overnight. It’s a great way to get a head-start on that flawless gloss finish you are looking for. For more information, visit

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About the author
William Sampson

William Sampson is a lifelong woodworker, and he has been an advocate for small-scale entrepreneurs and lean manufacturing since the 1980s. He was the editor of Fine Woodworking magazine in the early 1990s and founded WoodshopBusiness magazine, which he eventually sold and merged with CabinetMaker magazine. He helped found the Cabinet Makers Association in 1998 and was its first executive director. Today, as editorial director of Woodworking Network and FDMC magazine he has more than 20 years experience covering the professional woodworking industry. His popular "In the Shop" tool reviews and videos appear monthly in FDMC.