Oak can be darkened permanently by exposing it to the fumes of ammonia gas. Small articles made of the wood may be enclosed in a large box with well-fitting lid, along with saucers into which liquid ammonia – the gas dissolved in water – has been poured. The joint between be: and lid should be made as air-tight as possible by pasting paper along it.
The gas will soon fill the box. At the end of six hours the articles may be examined, and if not yet of the desired shade, fresh ammonia should be added and the box sealed up again. As soon as the requisite shade is attained, the wood should at once be rubbed over with lin seed oil, to prevent the gas leaving the wood. &
Should the fumigation have gone too far, however, oiling should be deferred until some has escaped and the shade lightened sufficiently. After the oil has dried, polish with wax polish .
Before use, test stains on pieces of wood similar to that to be stained. Allow the test stain two or three days to show its true colour, as some stains fade as they sink in.
Non-pigment stains should be rubbed over with a dry cloth immediately after brushing in. Pigment stains may be lightened, if too strong, by rubbing dark places while the stain is wet.
A scent spray is handy for applying water- and spirit-stains very evenly.