The fumes the wood is treated with is ammonia vapours. The result is that heartwood gets dark brown and sapwood greyish. The ammonia vapours will form a base, the base will partly be neutralized by the acids, tannins, in the wood, and thereby colouring the wood. The heartwood contains a high amount of tannin and therefore becomes darkest. The process takes from 2 to 20 hours and is comparable to developing films in old times. After fuming I ventilate the wood for a couple of days, then wash the surface in water, dry it, sand it and give it the surface treatment I plan.
The Woodturner on Kronens Hede in National Park Thy
Ernst Kempf - Kronens hede vej 12, 7700 Thisted
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