Long-term effects of lye on oak?

D

Dan D'Silva

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May 31, 2020
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Has anyone done this? I was trying out bleaching white oak with lye and peroxide, and I found that the first step turned the oak much darker and more brown -- grey-brown when dry, sort of an orangeish medium-brown when wet or oiled. As it happens, I'd been looking for a way of staining oak darker brown that would be appropriate for 18th-century cutlery grips, and since sodium hydroxide has apparently been used since the Middle Ages I thought it might be an option. However, I have to wonder whether it would have negative long-term effects on the wood itself or perhaps the finish. For instance, if I finish with linseed oil, is it going to saponify, and could that prevent subsequent applications of oil and varnish from adhering? Any thoughts would be much appreciated.

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When I have used commercial wood antiquing mixes, I always neutralized it with a white vinegar and water solution. Once the wood has oxidized/colored the desired amount wash well and rinse many times. Let dry completely and brush off with a wire brush. Rinse with the vinegar solution and let dry. Give one more freshwater rinse and let dry well for a few weeks.
 
Thank you! Don't know why I didn't think of neutralizing it. Is there a way of checking that the lye is more-or-less neutralized without making the wood too acidic?
 
Good advice above that will serve you well. A little faster more effective way is just to rinse with a solution of ammonia, a couple of ounces in a pint of water. The actual ratio is not that important, just rinse with the ammonia water mixture, then rinse with clean water (not even really necessary, but it makes people feel better🙂) and let it dry overnight. You can finish the next day.

Sam
 
Also, I would recommend something other than linseed oil as a finish. Although popular, it doesn't do much in the direction of protecting the wood or the color. It is popular primarily because it is almost impossible to mess it up.

Sam🙂👍👍
 
Thank you. I'll give it a test today.

I shouldn't have said "finish," really. I'm just using linseed oil to enrich the color, but I intend to give all my 17th- and 18th-century woodwork coats of oil-rosin varnish on top of the plain oil.
 
Sam Wilson said:
Good advice above that will serve you well. A little faster more effective way is just to rinse with a solution of ammonia, a couple of ounces in a pint of water. The actual ratio is not that important, just rinse with the ammonia water mixture, then rinse with clean water (not even really necessary, but it makes people feel better🙂) and let it dry overnight. You can finish the next day.

Sam
Click to expand...

Look up Fuming wood.... again with ammonia, I believe they used to darken white quartersawn oak furniture this way in the Arts & Crafts period.
They put the furniture in a sealed box with an open container of ammonia, and the fumes would react with the tannins and darken/blacken the woods.

works with other high tannin woods i heard, too.
 
Been reading up a little about fuming. It looks like it's not documented prior to the 19th century, although it should've been possible in the 18th using "spirit of hartshorn" or maybe stale urine (don't know if that would be strong enough).
 
Crag the Brewer said:
Look up Fuming wood.... again with ammonia, I believe they used to darken white quartersawn oak furniture this way in the Arts & Crafts period.
They put the furniture in a sealed box with an open container of ammonia, and the fumes would react with the tannins and darken/blacken the woods.

works with other high tannin woods i heard, too.
Click to expand...

Yes, it does work, with oak and other woods. Just not very well with department store ammonia.

Sam
 
Ammonia darkens oak, it reacts with the tanines in oak.
That's why oak beams used in stables get so dark, it's the fumes from animal urine.
As said, it's the fumes not the liquid that works.
 
Agreed. That being said, D Dan D'Silva the ammonia solution you use to neutralize the lye won't have any adverse effects on your color job or the finish. Have used this process many, many times. Good luck with it.👍

Sam🙂
 
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