Matt is a professional painter who owns and operates his own painting business, specializing in interior and exterior house painting.
Why Use Grain Filler?
If you're painting grainy wood, you really should use filler to minimize the surface texture and improve your finish. I always use grain filler to smooth the surface of oak cabinets I am prepping for paint. Without filler, the deep cracks in oak grain are difficult to prevent from showing through paint, especially if you're spraying instead of rolling.
In my experience, most of the grain filler I've used, including Aqua Coat, doesn't completely remove the natural pattern of oak in one coat, but one coat does fill cracks in the wood, which makes them less noticeable through paint.
Aqua Coat is a clear, water-based gel that can be used on a number of wood surfaces, including kitchen cabinets, tabletops, mantels, and guitars. There is also a newer version too that's white in color and performs better than the clear gel version my review is based on. This product fills wood grain and helps seal it to help prevent tannin bleed in painted wood.
I have only used this product to prepare oak cabinets for primer and paint, so my review is based solely on my experience using it for that purpose.
Does Aqua Coat Wood Grain Filler Work?
I tried this product based on a recommendation from another painter. It's a water-based gel with a funky odor that smells like M&M's. It's messy to work with, but it's performed pretty good when I've used it to prep cabinets I'm spray painting. It doesn't completely mask the grain, but it fills the deep cracks that would otherwise show through the paint.
Applying this product on twenty-plus cabinet doors is very tedious, but worth the effort if you want a smoother finish. I apply two to three coats, which fills and reduces the grain. If you want to totally rid the surface of grainy cracks and holes, one coat is not enough.
Completely leveling out the grain pattern with the surface would take several coats because this product is very thin and shrinks a little as it dries. I have yet to find grain filler that totally levels out grain with the surface in one coat. The most important part is filling the cracks so you don't see dark spots when it's painted.
As of this writing, this product is only available through Amazon. The pricing for a quart of Aqua Coat is $45. The pricing is similar to other products I've used. Most of the cabinet jobs I've used this product on required two to three quarts to fill everything, but the amount you need depends on the number of coats being applied and the size of your project.
Applying Aqua Coat Grain Filler
The surface must be clean and dust-free. I wipe the surface with a tack cloth first to remove dust. The company itself suggests using a small squeegee, or putty knife, to apply the material, but an old credit card (or plastic taping knife) worked well for me.
A credit card makes it easy to work the gel into the tight corners. I don't recommend using a metal taping knife because that can scratch the surface of the wood. Wearing work gloves is a must because this stuff is very messy.
You must apply this product in very thin coats. Do not apply this product in thick layers or the sanding will be very difficult. Applying the material too heavily also extends the dry time.
The gel dries in a glossy film that must be sanded before top coating. You can sand the surface with a sanding sponge, or an orbital sander, using 220-grit sandpaper. If you apply a thin coat, sanding is easy. Depending on what you're using this product for, it could take three or more coats if you want to level out the grain more with the surface, but a couple of coats will get rid of the cracks and pores in the wood. When applied thin enough, the gel dries in about one hour.
When applying Aqua Coat, a little goes a long way, and you can waste the material very easily by over-applying it. The company recommends waiting twenty-four hours before top coating with primer, paint, or lacquer. I let the filler dry overnight before priming.
It's important to note that you cannot apply an oil-based polyurethane coating over this grain filler. The polyurethane won't bond well with the filler and could result in peeling and failure. When using a sealer, the sealer must be wax-free as well. You can coat this product with oil-based primer, or shellac primer, like BIN.
Read More From Dengarden
Is Aqua Coat Good for Cabinet Painting?
I primarily use Aqua Coat for prepping oak cabinets I paint and I do recommend it. There is a newer white paste version that's thicker and easier to work with than the gel version this review is based on. The product starts to fill the grainy cracks in wood in two to three coats, but if you want to smooth out the grain on your oak cabinets even more, you'll need to apply additional coats. Most of my customers want to reduce the grain without visible cracks in the paint, so two to three coats is good enough for that purpose.
Most grain filler, at least the products I've used for oak, require more than one coat to reduce all visible grain cracks in the paint. The white paste version of this product is a nice improvement over the previous gel version. The white paste makes it easier to see the product in the grain during and after application. I use the white grain filler now instead of the clear gel.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: Could you use aqua coat on the face frames of installed oak cabinets or would the material run or sag too much?
Answer: Yes, you can use it on the wall boxes and the doors. It won't sag. Be careful not to leave heavy edges, or globs in corners, otherwise it's difficult to sand.
Question: Can you use Aqua Coat Clear Wood Grain Filler as a topcoat if you’ve already paint but want to hide grain?
Answer: This product is a filler that should be used to fill the grain before applying paint. While you could use it to fill the grain on an already painted surface, doing so will alter the finish of the paint because the filler's glossy. Aqua Coat is also meant to be sanded and top coated with either a protective finish, coat, or paint.
Question: Do you sand oak cabinets prior to the first coat of wood grain filler?
Question: Can you apply after 1 coat of primer as well?
Answer: Yes. Priming first makes it easier to see the cracks when it's white. Prime a second coat over the filler.
Question: I’m using Aqua Coat clear wood grain filler on a Northern Ash guitar body. How much do you thin the gel with water? Is pancake batter consistency correct, as I’ve seen with other fillers?
Answer: I've never thinned this product. It's very thin out of the container so I'm not sure you'd need to for your application. I recommend reaching out to the manufacturer.
Question: What are your thoughts on how well this product might work on teak interior stair nosings to match the prefinished teak flooring I'm using for the treads?
Answer: I have only used Aqua Coat for filling the grain on oak cabinets. I would contact the manufacturer.
© 2017 Matt G.
Matt G. (author) from United States on August 16, 2020:
Tannin is hard to stop without the right primer. Extreme Bond primer is latex and it won't seal oak to stop tannin bleed. You can prime over and over with latex and the yellow stains will reappear. You need to use oil primer, or BIN (shellac primer) to seal the oak then problem solved. I have articles on primer and cabinet prep. Check out my article list.
Melissa Christianson on August 15, 2020:
What do you Recommend to stop tanning coming through your primer and paint?
I use Sherwin williams extreme bond and Sherwin williams Emerald Urethane paint .
I clean with TSP , sand etc... but still get tan stains that are very hard to cover..
I spray doors and drawers . I think I have this problem with oak cabinets more then other woods ..
thank you, mel
Matt G. (author) from United States on October 08, 2018:
Honestly, I'm not sure because I've only used it under shellac primer. It should be fine, but a quick call to their customer service doesn't hurt.
Shane on October 07, 2018:
Will this grain filler bond with acrylic alkyd water based primer?