The Craft: Avi’s Fuming Box

Oak contains tannins which, when exposed to ammonia fumes, darken the wood. Enclose an oak frame in a box with dishes of ammonia and you get 400 years of aging overnight. Paul Roehl paintingThis frame on Paul Roehl’s painting, “Spring Coast Range,” at right, is fumed. Oiled, the color is a cool brown, which as is frequently harmonizes perfectly with the painting, especially with a tonalist palette like Paul’s.

You can fume a frame in a cardboard box wrapped in a plastic bag, but it’ll start feeling makeshift after a few uses. Avi, who does our finishing, got tired of messing with that arrangement and made a simple plywood box with a clear acrylic lid. The bright red line is an old yoga mat he cut up for gasketing to seal the lid. He also sealed all the seams of the box with silicone sealant. Four draw latches secure the lid tightly. The ammonia’s three or four times stronger than your ordinary household stuff—you have to get it from an industrial chemical supplier—so, one reason you want the box well sealed is that if you get a whiff of the ammonia, it’ll knock you over. The depth of color and speed with which the wood darkens depends on the amount and strength of the ammonia, the amount of tannins in the wood, and length of exposure. The clear lid let’s you check the progress without having to open the box.

woodworker and fuming boxAfter fuming, we often just oil the wood and wax it (with solvent-free pure boiled linseed oil and linseed oil wax—from these guys or this guy), but if the color’s not quite right, the wood can still be stained—or dyed. We use water dyes rather than stains. Our dyes are very good quality and penetrate the wood well. But there’s nothing like the depth and mellow effect you get by fuming.

The frame you can see inside Avi’s fuming box is also for a Paul Roehl painting, one that we’re framing for Beloved California IX, our big annual show—opening just four weeks from today!

 

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