On a recent trip to Craftsman Farms I had a conversation with the docents about fuming oak. We agreed that there were varying opinions about why Gustav Stickley fumed his oak–some thought it was to “Pop” the ray fleck pattern from the surrounding grain, while others believe he was trying to deaden the appearance of the ray fleck patterns. The more I thought about the contrasting views, the more curious I became. So I decided to do a little poking around and see what I could find.

Gustav Stickley did a great deal of writing about his furniture, including building and finishing techniques. In this quote from the Craftsman Magazine he hints at his thought about finishing oak:

“There are many varieties of oak in this country, but of theses the white oak is by far the most desirable, both for cabinetmaking and for interior woodworks. One reason for this is the deep, ripened color it takes on under the process we use for finishing it-a process which gives the appearance of age and mellowness without in any way altering the
character of the wood.”

“Mellowness.” Hmmm reminds me of high school in the 70’s, where I was always trying to “mellow out, man!” Anyway, Gus later offered clarification on what mellowness was all about when he wrote:

“In my experiments, however, I decided that a far more pleasing and beautiful result would be obtained by softening rather than heightening the distinctiveness of the flakes. So for months I persisted in my endeavor to discover a way by which I could “bring together,” harmonize, as it were, these two markedly contrasting features in the same piece of wood.”

From those two passages, I’ve concluded that Gus’ intent was to try and minimize the contrast between the ray fleck, or flakes as Gus called them, and the surrounding grain. But I have to admit I have seen examples of fumed wood that appear to have a “pop” effect to the ray fleck pattern. A technical explanation of fuming, I think explains this
phenomenon.

“Fuming turns the wood some shade of brown depending on the tannin content of the wood, ammonia strength [used in the fuming process], and how long the wood is exposed to the ammonia fumes. So the ray-fleck pattern AND the surrounding grain do get darker. However, the ray-fleck patterns still reflect light at a different angle than the surrounding wood. At certain angles the contrast between the darker wood and the
ray-fleck patterns look more dramatic and is the reason people describe the effect as “pop.” From the opposite angle, the same rays and flecks will blend in.”

So there you have it. I think Gus’ intent was to bring the ray fleck pattern and surrounding grain together, but the physics of light would only allow it from certain angles.