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Aging Redwood

S. Clark

S. Clark

Joined
Sep 30, 2005
Messages
201
Likes
1
Location
Santa Rosa, CA
Website
www.ispinwood.com
Does anyone have any pointers on how to age redwood? I'm after that nice gray color which occurs after it has been outdoors for a few years. A particular piece I'm working on has some naturally aged areas which I'd like to match. I have achieved the necessary texture through the use of a torch and wire brush. And I've tested samples using a baking soda solution to darken the wood. This works for darkening (blackening) but I'd like the gray surface effect too. Any thought?

- Scott
 
Hereabout, that aged look comes from surface leaching and high-energy UV bleaching. I've used acid on a few pieces to try and simulate barnwood after kicking out the soft grain with a wire brush with indifferent results. I'd buy a UV and get it real close to my sample, spraying the surface every day and letting it dry. One sample could use muriatic acid, if you're careful.
 
Mmmm... Hadn't thought about UV. I think my wife has some lights that are high in the UV spectrum. She grows a lot of house plants and cactus and has different plants sitting under various light (only inches away). Acid sounds dangerous but I'll investigate that idea too. I tried household bleach to no effect but maybe I should try repeated applications or soaking the wood. Thing is, I only want to treat certain areas of the piece I'm working on. Spraying is a good idea. I could mask out the areas I want to leave alone. I have a temporary sanding sealer on those spots right now.
 
There's actually a 2 part wood bleach out there designed to lighten or remove color. Unfortunately, I'm guessing the only way you'll get that nice gray color is through UV bleaching, which will likely take quite a while, even with the lamps. The only other option I can think of other than just trying to get a consistant color other than the gray, would be sticking with it the way it is and using the grayed parts as a feature and as part of the slowly evolving and changing nature of a wood piece.

Good Luck,
Dietrich
 
Scott,
Muriatic acid is not too bad. Yes it is an acid and you have to be careful - but in small amounts - used outside. Never hurts to have a base around in case of a spill - something like baking soda. Muriatic acid is used in swimming pools to control the acid level in pool water. Many years ago - my father and I used to use it for flux when soldering. As with any chemical - be careful of the fumes (do it outside) - watch for spills (water will dilute and baking soda will nutralize). Let us know what happens and what works.
Hugh
 
Scott,

Rather than Muriatic, I'd suggest you get some Oxalic acid which is used as a 1-part wood bleach and brightener. It's usually available in paint stores in crystal form, and you can vary it's effect by how you mix it. I doubt that anything will be a real substitute for the combination of Time and The Elements.

You might get closer to the weathered texture by a little light sand blasting if you have a compressor available.

Mark
 
Don't remember when or where I read it, but the grey "weathered" color in Cedar is actually caused by organisms... I would suppose that to be true for other woods as well.

I guess you could refer to them as "elements"....

Can anyone substantiate this random memory?
 
Organisms must be on the Perodic Table of Rejected Elements.

If you will supply me with new deck boards, you can have my nice gray ones. Some of them in shady areas even have a wonderful green patina -- no extra charge.

Bill
 
underdog said:
Don't remember when or where I read it, but the grey "weathered" color in Cedar is actually caused by organisms... I would suppose that to be true for other woods as well.

I guess you could refer to them as "elements"....

Can anyone substantiate this random memory?
Click to expand...

Nope, but I can direct you to a great wood site where you can look up weathering, its causes and consequences.

http://www.fpl.fs.fed.us/ Where searches on weathering indicate that it's sunlight and oxidation which are the culprits. Thus the use of strong acids - oxidizing agents - and sunlight-simulating lights to accelerate the weathering.

Black stains from mildew can form on less-resistant woods than cedar, and moss and lichens do grow on the north sides of barns, even those made of cedar. White rot fungi require longer periods of moisture above 18%, but they can certainly degrade the lignin and create cubical checking. That stalwart of western privacy fences "pecky cedar" is a good illustration of it.
 
After my last post on this subject, I remembered a short ditty my father used to say - this about the use of acid - - Little Willie was a chemist, Little Willie is no more, For what he took to be H2O, was H2SO4. Sorry - I had to do it. Pops would have loved it.
Hugh
 
Thanks to all for the ideas. I've got some sample boards started now to test some of these. I'll post up what I learn. Maybe I can photograph the samples?I'm going to check out the site that Michael listed and see if there is something there that will give me a clue. In the end, I might have to concoct some sort of gray stain that'll simulate what I want. I don't know? I'll keep you posted.

- Scott
 
I have successfuly "aged" cherry using Red Devil lye. In a pinch even crystal Draino will work. Don't know about redwood but might be worth a try. You control the aging by how soon you rinse off the lye. Be careful of these products also, they can produce some nasty burns.
 
Lye, Mmmm... I'll look into that. I was testing oxalic acid this weekend without result. I also purchased a couple different types of stain to attempt a simulation and have some samples in progress. So far, baking soda is the only thing that leads the right direction. I found that it darkens the wood substantially but begins to build a dusty gray residue if a strong solution is applied several times. Still not really the silvery, driftwood color I'm after though. I'll give lye a try. Thanks.
 
S. Clark said:
Lye, Mmmm... I'll look into that.
SNIP
I'll give lye a try. Thanks.
Click to expand...

Don't bother. Dangerous, and what lye does to "age" cherry is darken it. It's high pH cousin, ammonium hydroxide, the aequous solution of ammonia, is often used to darken woods with sufficient tannins. Arts and Crafts furniture was made of fumed oak.

Above all, even if you try, avoid use of drain cleaners which have aluminum or magnesium in them to cause hydrogen gas evolution to loosen grease by mechanical action. You want lye alone.
 
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