Adding Age to CherryComments (0)
This article is from Issue 35 of Woodcraft Magazine.
A side-by-side test compares six ways to make new wood look old.
By Craig Bentzley
Cherry is revered not just for its impressive working properties, but for the way that the wood naturally turns from pink to deep, reddish brown, and continues to get better looking with each passing year. Searching for an easy way to accelerate the look of old cherry without the wait, woodworkers have tried all sorts of “time in a bottle” treatments. Having experimented with many different techniques, I was happy to get a chance to pit the time-adding treatments in a side-by-side test in order to separate fact from fiction.
I started my myth-busting mission by weeding through several decades’ worth of written and anecdotal evidence, including countless threads on the Internet. After identifying six “sure-fire” recipes, I applied each to a single cherry board. Knowing that sunlight would play a part in the final color, I masked off half of each sample and arranged the boards in a south-facing window for four months. While the outcome will be more conclusive after a year (or 10), I think the jury is officially in. (To see the samples, turn to the chart on page 40.)
Choosing a winner in the cherry race is more than just a photo-finish. In addition to color, there are other factors that warrant careful consideration. Several of these treatments are so dangerous that they might convince some to wait for the wood to change on its own. Here’s a rundown of what matters most so you can pick the right treatment for your next project.
Speed vs. safety
Like many other woodworkers searching for an instant-aging formula, I’ve experimented with all sorts of chemical cocktails and, in my opinion, the risks outweigh the benefits. Chemical agents—sodium hydroxide, potassium dichromate, and potassium permanganate—might be fast operators, but they are also dangerous. Check the MSDS sheets. If you’re not prepared to don splash-proof goggles, rubber gloves, and a vapor respirator (Photo A) to defend yourself from burns, blindness, or worse, don’t do it. To make matters worse, these chemicals are potentially explosive. In order to control the chemical reaction, they must be added to water; reverse this simple step and you might be headed for the hospital.
Treating cherry with sodium hydroxide is akin to a chemistry experiment. If you don’t have the safety gear, don’t do it.
Boiled linseed oil (BLO) and polyurethane are reasonably safe, but they shouldn’t be taken for granted (Photo B).
Each year, oily rags start scores of woodshop fires. To avoid the risk of spontaneous combustion, discard oily rags in a pail of water or lay them outdoors to dry before tossing.
Dye offers a reasonably safe middle ground. Wipe it on, let it dry, and you’ve got a cherry look that’s ready for a topcoat. Admittedly, dyes are carcinogens, but they’re not explosive. Gloves and common sense keep risks to a minimum.
Consistency, control, and colorfastness
Color can be broken down into the three Cs: Consistency (from one board or project to the next), Control (ease of application), and Colorfastness (how long the color stays that way).
Chemical treatments are the most unpredictable in all three categories. These treatments can react differently even when using boards cut from the same log. They’re also difficult to apply uniformly—drips, runs, and lap marks can be impossible to correct.
Surprisingly, the “instant” color change is short-lived. From personal experience, I’ve found that, in a few years, chemically treated pieces are impossible to distinguish from wood treated using safer methods. As shown on the following page, the chemically treated samples have already started to fade.
Aniline dyes win points for consistency and control. These attributes can be helpful when matching boards to make a top, or coloring sapwood to blend with darker heartwood. Unfortunately, dyes aren’t colorfast. The camouflaged sapwood will fade over time, while the heartwood will continue to darken, revealing the lighter sapwood streaks.
Because they enhance color more than change it, boiled linseed oil and polyurethane are the most consistent and easiest to control. But this also means that they won’t change the color of sapwood. On the plus side, fading is not a problem; each looks better with every passing year.
Topcoats take time
With the exception of wipe-on polyurethane, all of these treatments require an additional topcoat. Since this step adds time to your finishing, it’s something you need to consider when time is short.
Aniline dyes and boards that you chemically treat can be topcoated with any
finish as soon as they’re dry. I apply a seal coat of dewaxed shellac to prevent dye from bleeding into subsequent topcoats.
Linseed oil will add the most time to your finishing schedule. The oil needs three to five days to dry before topcoating. Once it’s fully cured you can use any finish, but shellac or alkyd varnish will avoid compatibility problems.
After comparing the various treatments, I don’t think any woodworker needs to turn his workshop into a chemistry lab.
If you need to add color quickly, use dye. If you can build the project ahead of time or can convince the recipient to be patient, go for polyurethane or BLO and put the finished piece in a sunny spot to let nature do the work.
Truth be told, “aged cherry” color is a moving target. What oxidation and ultraviolet give, they will take away. Eventually, the deep reddish brown cherry will fade to light reddish gold, but the problem will be something for your grandkids to figure out.
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