Authentic Fume Wood Finish for Oak

A fume-finish is a techinque used to color the wood. This type of finish is was started in the 1920 as has been used for all types of arts and crafts. This portion of the project requires industrial-strength 26 percent aqua-ammonia solution. The vapors from the ammonia will darken the wood and help bring out the grain pattern

Materials:

Plastic tent made from scrap lumber and clear-plastic sheeting
26 percent aqua-ammonia solution (available from chemical suppliers)
Glass container for ammonia solution
Tung oil
Paintbrushes
Rags
Protective gloves and goggles

Safety Alert: Always wear safety glasses and gloves when working with wood-finishing chemicals and solvents.

Steps:

A plastic "tent" is constructed from scrap wood and clear plastic. Place the unfinished item inside the tent (figure A).
With the item inside, seal up the tent. Place a container of the 26 percent aqua-ammonia solution inside the tent (figure B), then seal up the opening. Left overnight, the ammonia vapors react with the tannic acid in the oak, giving the wood a dark, aged, silvery-brown color and helping bring out the medullary ray fleck pattern in the wood grain.
Important: The fume-finish process requires 26 percent, industrial-strength aqua-ammonia, which is available from chemical supply houses. Don't attempt to use ordinary household ammonia for this process, as ammonia at that strength will not work.
After the ammonia treatment, apply of a couple of coats of tung oil using a paintbrush, then rub the oil into the wood with clean rags (figure C).
Hand-rubbing brings the wood to its final lustrous finish (figure D).
The silvery effect from the ammonia-fume process provides an appropriate wood tone to this classically styled arts and crafts piece and works nicely with the understated detailing.

Figure A

Figure B

Figure C

Figure D