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3 Great Ways to Hide Sapwood in Walnut

by Mark Stephens | January 1st, 2014

Even colored walnut lumber

Look close. This piece of walnut is not only finished with a clear lacquer but the light colored sapwood has been evened out to nearly match the heartwood. Woodworking with walnut today means dealing with the sapwood. Here are 3 ways.

Few people approve of pale sapwood in their walnut lumber,  but in the words of  Jim, a salesman at one of our faithful walnut suppliers back east, “When people ask me for a 100% heartwood face in walnut, I just tell them they’re dreaming.” You may be tired of hearing that sapwood isn’t considered a defect when it comes to grading lumber, however it is an industry fact. Lumber grade is a mathematical computation of the amount of clear wood in a board – so says the National Hardwood Lumber Association, the organization responsible for defining the rules of the lumber trade.

“But it’s a defect to me,” says the woodworker.

So what’s a woodworker to do? Fortunately, lumber producers separate their walnut inventory not just by grade but also by color. The good news is 100% heartwood walnut can be had; the bad news is few can afford it. For the most part, about the best balance between color, cost, availability is called 90/70 heart: that means 90% heartwood on the face, 70% heartwood on the back. Remember, lumber has two broad sides, a face and a back, and when building furniture and cabinetry, only one side is displayed in the final product.

Sure, it’s possible to find some 100% heartwood boards from time to time, but on a consistent basis and in large quantities? Not really. And therefore, when you visit your nearest lumber supplier, you’ll never have a perfect pile of full brown walnut to select from. Full heartwood boards are the exception to the rule, so it’s time to look at how woodworkers are using walnut in today’s woodworking.

You’ll find a number of discussions and blogs about this topic, and a good one in particular is this found at Lumber Jocks, www.lumberjocks.com/topics/10565, which discusses three ways woodworkers overcome sapwood.

3 Ways to Deal with Sapwood in Walnut:

  1. Cut sapwood off, and/or hide the sapwood on parts that will not be seen frequently
  2. Live with sapwood in your finished project
  3. Use a dyeing and staining process to make the color even

Those first two are straightforward.

Dyeing and staining needs some explanation, though. Since you’re not going to be able to go the woodworking store and buy a bottle of Sapwood Hider right off the shelf – alas, no such miracle exists – there are a couple of steps involved, but they’re easy.

Walnut board

Walnut board clearly shows a sapwood edge until the piece is dyed, sealed, stained, and finished. A saw kerf line separates the two sections.

For this method, we’re specifically talking about dye and there are a number of dyes on the market, usually mixed with water or denatured alcohol. Dye is different from stain, as dye doesn’t obscure the grain, which is pretty important when using walnut.

The basics:

1. Apply a very diluted dye in a color of your choice to the entire piece, heartwood and sapwood. The dye used in the pictures here is Behlen Solar-Lux™ medium brown walnut color. Solar-Lux™ is UV resistant and fade resistant, which is great because when walnut is left natural, it eventually turns very tan. Walnut ought to be dyed or stained anyway to retain a pleasing color. Note: Medium brown walnut Solar-Lux™ dye will appear orange when you apply it, but that’s okay. The next steps will bring the color back to dark brown.

2. Seal the wood with a light coat of sanding sealer or shellac. This needs to be thin to allow for the next step to have some effect.

3. Apply an oil-based stain on top of the sealer. Wipe it on, wipe it off. This adds a touch of pigment to the pores equally to you get a consistent color across the board.

4. Apply your clear finish of choice. Varnish, lacquer, etc.

It should go without saying that you should always test your dye process on a few test pieces before committing the dye to your final product. You’ll need to test different dilution ratios of your dye before you get the color you want.

Dyeing walnut is not very difficult, but it will take some time. However, you’ll greatly increase your yield of wood and you’ll make the beautiful walnut color last much, much longer than you would if if were to leave the wood natural.

Sapwood stripe along the edge of a walnut board

This part of the board is finished with just a clear coat of Zinsser Sealcoat and lacquer. The sapwood strip stands out. Eventually the color of this board will lighten.

Closer, showing the change in sapwood color

Closer, you can make out where the sapwood is nicely colored and very nearly matches the heartwood color thanks to the dye process

Even colored walnut lumber

The end result is a pleasing walnut color that will last a lifetime.

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This entry was posted on Wednesday, January 1st, 2014 at 6:20 pm and is filed under Tips and Tricks, Wood Conversations. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

13 Responses to “3 Great Ways to Hide Sapwood in Walnut”

  1. Andy Pensavalle says:

    I just received my shipment of the thin walnut featured in last week’s email. Wow, what a buy! The wood is just beautiful!!! Any of you guys that make boxes or small craft projects should jump at this one. Thanks, Mark.

  2. J. Griffith says:

    I have only purchased Mesquite once. It was a dark color and it did not resemble the pictures I have seen on the net. Is the source a determining factor if I wish to find the darker mesquite lumber for furniture ? Perhaps darker mesquite is from more equatorial regions? Please assist. Thank you!

    • Mesquite changes color quite drastically with time. Freshly cut, it’ll be very light tan. But as it ages it goes to a rather dark brown, you’ll see a slight difference within a couple of weeks. Exposure to light accelerates the change. Additionally, the finishing process one uses on a piece of mesquite has a drastic effect, so that’s a very important variable that should be considered. The source region plays a role, but it’s nuanced.

  3. Edison says:

    Hi, how to hide sapwood in oil finish?
    Still using staining underneath the 2nd layer?
    Will waterbased or NC based staining will help?

    • Can you be more specific about the oil finish? What kind of oil finish?

      Something like tung oil or boiled linseed oil will not work as the top coat in the process above because those need to penetrate into the wood. The washcoat of shellac or sealer (the step between the dye and the stain) prevents that. However, you can apply a varnish instead of a lacquer for the top coat after the stain. But maybe that’s not what you’re asking.

      It’s important to have a grip on what role the different products play. The dye establishes, as much as possible, an even-colored base layer upon which to build, and you can do any number of coats of dye or any dilutions to suit your tastes. The thinned sealer prevents the next step from coloring the wood too much and obscuring the grain. The oil stain delivers colored pigment to all the tiny pores in the wood without coloring the surrounding wood (much). The overall effect appears to blend the sapwood and heartwood. The bottom line, an oil finish just doesn’t fit into this equation.

      With that, it’s possible to tint oil and perhaps arrive at nicely blended heart and sap. For example boiled linseed oil can be tinted with linseed oil-based artists paints. You could try that for the first step instead of the dye I used. Maybe it’ll do what you want. Let it fully dry. Then continue with the steps above — apply the thin coat shellac or sanding sealer, then wipe on/off the stain. That works too, though the results can differ obviously, perhaps you’ll like that look more. That would be the only advantage (that I can think of) over using dye.

      Also, a water based stain miiiight work in place of the dye in the first step . . . but I don’t know. But stick with the oil-based pigment stain in the third step.

  4. Doug says:

    Hey Nick,

    I must be weird too; I like sapwood (and its variegated look) as well.

    So I’d like to maintain the original look of the wood while preventing the fading that you indicate will occur. Can you do that? How?

    Thanks for the tips!

    Doug

  5. Yavuz B. says:

    Looks awsome tough.whats the stain color ya use?

  6. Tom H. says:

    You must have read my mind. I am in the process of building a walnut bench and have been trying to figure out how to properly “cover” the sapwood. I just got my answer. Many thanks.

  7. Nick says:

    I must be weird, I LOVE sapwood.

  8. Joe Tripodi says:

    Do you think this method will work to darken a light colored batch of veneer?
    !