Tuesday, February 5, 2008

Some thoughts on an Arts and Crafts Finish

Most of the recipes for the "authentic" Arts and Crafts finish that I've found in the modern literature are concerned with making the medular rays in the Quartersawn White Oak "pop", that is, highlight the flakes. During my reading of "The Craftsman" at the digital archive I came across this passage by Stickley.

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 flake. 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. This was finally effected by the use of ammonia, either by direct application or by fumes. The ammonia combines with the tannic acid in the oak to produce a chemical change, and thus "tone down" and color the flake to the desired shade. As far as I know this is the only practically successful method yet discovered to cope with the difficulties offered by the ray flake. Pigment applied to the surface of the flake has no appreciable result, as it is almost as hard and impenetrable as glass. In what I have written above I would not have it thought, because of this somewhat lengthy description of my own experiments, that I make any claim to the discovery of the use of ammonia. Many others have used it, and still do so, and others may have produced the same results on oak, but in my case it was the outcome of personal experimentation.

Now this leaves me in kind of a dilema, my favorite finishing recipe are all centered around making the flakes "pop". I think that part of the beauty of the Arts and Crafts style if they distinctive look of the quartersawn oak. The method I prefer is dying the wood with a concentrate disolved in water, to give the base color for the wood, followed by a coat of shellac, a darker gel stain, more shellac, and finally a dark wax. But from the reading and talking to a few professionals I've found that the most authentic way to achieve an authentic Arts and Crafts Finish is by fuming the quartersawn white oak with aqueous ammonia (NH4OH), this is the method that Gustav Stickley popularized.

The fuming is not an especially difficult process, but it requires a good deal of care, for the piece must be put into an air-tight box or closet, on the floor of which has been placed shallow dishes containing aqua ammonia (26 per cent). The length of time required to fume oak to a good color depends largely upon the tightness of the compartment, but as a rule forty eight hours is enough. When fuming is not practicable, as in the case of a piece too large for any available compartment or one that is built into the room, a fairly good result may be obtained by applying the strong ammonia directly to the wood with a sponge or brush. In either case the wood must be in its natural condition when treated, as any previous application of oil or stain would keep the ammonia from taking effect. After the wood so treated is thoroughly dry from the first application it should be sandpapered carefully with fine sandpaper, then a second coat of ammonia applied, followed by a second careful sandpapering


Some pieces fume much darker than others, according to the amount of tannin left free to attract the ammonia after the wood has been kiln dried. Where any sap wood has been left on, that part will be found unaffected by the fumes. There is apt also to be a slight difference in tone when the piece is not all made from the same log, because some trees contain more tannic acid than others.

So with this in mind I'm going to attemp an experiment, I've obtained some aqueous ammonia from a local blueprint supply house and after consulting with my friends that us it, I'm going to fume some samples to different darknesses and finish them, then I'm going to compare them to my samples of the recipes I have been following and decide which is more, a. authentic, and b. more visually pleasing to the modern eye. Stay tuned for the process, details of each recipe, and the results.

Fine art is that in which the hand, the head, and the heart of man go together.

John Ruskin

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