# Asking For Feedback On A New Article On Wood Color Changes



## phinds

I would appreciate feedback on this new article that I've added to my site. It's a discussion of what kinds of natural color changes occur in woods, what causes them, and what (if anything) can be done to prevent them. I'll probably work on it a bit more, but it's close to finished.

http://hobbithouseinc.com/personal/woodpics/_color change/index.htm

I'd particularly like to hear if you think I have anything wrong or if there's something significant that I've left out in this discussion.

Thanks.


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## Blueglass

Informative article. The first picture is the first drum I ever made. It is still pretty much the same color. The second I took to the beach and worked on while my wife surfed on a semi-regular basis. The cherry comes from the same log. I see the second as being more red. I know the lighting is different but seeing these in person I see it the same way. I don't know it this helps any but I thought I'd throw it out there. Both finished in Tru-oil.


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## Mike Jones

I liked your article a lot, and appreciate the early/late pictures. I would add: Walnut (fades dramatically) and one of the most disappointing is the color change of manzanita and it's cousin, madrone. I have found boiling both of those species delays the fading and by a very noticeable margin. Perhaps the heat acts as a mordant on the natural dyes...just a guess.

I also was suspect regarding the UV blocker laced polyurethane. I was not aware that there was such a thing in the consumer marketplace. I did a quick search and turned up these "learned" responses on other forums.

_"As a hardwood flooring manufacturer which also operated a UV cured finishing line, the UV lamps in simulating sunlight enabled me to experiment with many UV protected finishes. In my experience there is no such thing. - See more at: http://www.hardwoodflooringtalk.com...ection-exist-t10523.html#sthash.F8Q1HEm0.dpuf" 

"Normal (interior) Polyurethane does not have these additives. Some protection is created simply from the film, but not much. Exterior PU's should have Hindered Amine Light Stabilizers (HALS) coupled with UV blockers called Tetratrazioles (If I can remember the name correctly). These additives can be added to any clear film finish - varnish, PU, Acrylic Urethane etc. but only for those designated "exterior", although some "exterior" finishes may not have these additives - they are expensive, and cheapo companies probably have very little loading of them. 
HALS are free-radical absorbers. Free radicals are sheared electrons that come off of a polymers molecular chains due to bombardment of UV light from sun. Enough electrons lost, and the chains breakdown. UV Blockers (tetratrazioles) are non-pigment (clear) blockers of the actual UV light. The best blockers of UV light is pigment itself, white being best, but in clearcoats, a little higher-tech additive is required (can't remember how it worked, but it blocked UV quite well).
Both types of additives are meant to be used together. 

I used them in 1-1/2% to 2-1/2% loadings and that is a lot - which is why certain clears are more expensive. You still need an elastic formula though, for longevity in a clear. These additives are great for protecting epoxy from blush, which is why you need to overcoat epoxy with marine varnish. "_


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## DKMD

Looks good to me, Paul.


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## phinds

Mike Jones said:


> I liked your article a lot, and appreciate the early/late pictures. I would add: Walnut (fades dramatically) and one of the most disappointing is the color change of manzanita and it's cousin, madrone. I have found boiling both of those species delays the fading and by a very noticeable margin. Perhaps the heat acts as a mordant on the natural dyes...just a guess.


 
Boiling ... thanks, I hadn't thought of that as a color stabilizer. Walnut and madrone are just a couple of the MANY woods that I did not name. As I said in the article, I wasn't trying to get all the woods that change color but all the types of color changes.


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## SENC

Good article, Paul. Heart pine is another wood that has a good color change. An 8-10 year old heart pine (longleaf) floor is much more colorful and attractive than a newly laid floor (even when the wood was milled from very old reclaimed heart pine beams).


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## Molokai

Good article. I have one question after reading. Does stabilized woods also darken over time or change color?


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## phinds

Molokai said:


> Good article. I have one question after reading. Does stabilized woods also darken over time or change color?



I've never used stabilized wood so don't know but I would think that the stabilization process surely must at least retard color change, if not prevent it completely.

Reactions: Like 1


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## SENC

Some stabilizers say it prevents... I suspect over the long run it retards. But between eliminating oxidation and providing (supposedly) uv protection, it is probably the best option.

Reactions: Like 2


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## Treecycle Hardwoods

Paul your article was a good one. I read it a day or 2 ago and am just getting around to posting some feed back. Starting off with the reasons for color change was good. The one reasons that resonates with me relates to initial milling of logs. We have a fair number of FBE fans on the site. We are often teased with great colorful pix of these beauties on the mill (yes I am a tease) Soon after milling those vibrant reds, oranges, and pinks fade. You covered the reason for this well in the article I hope it resonates with other members. I see some great looking FBE being past over when all it needs is a coat of polly (or any oil based finish) to get the color to pop again. Walnut is another quick color changer off the mill. Fresh sawn walnut is olive green! Quickly after milling(30-60 min) it is a nice chocolate brown.

Fbe is also a good one to discuss UV effects on wood.... 

Walnut is also a long term color changer...

Great info in the article. All woodworkers should have basic knowledge on the topic and your info is presented in terms that most can digest. Thanks for taking the time to write it and share with the group.


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## phinds

Treecycle Hardwoods said:


> Paul your article was a good one. I read it a day or 2 ago and am just getting around to posting some feed back. Starting off with the reasons for color change was good. The one reasons that resonates with me relates to initial milling of logs. We have a fair number of FBE fans on the site. We are often teased with great colorful pix of these beauties on the mill (yes I am a tease) Soon after milling those vibrant reds, oranges, and pinks fade. You covered the reason for this well in the article I hope it resonates with other members. I see some great looking FBE being past over when all it needs is a coat of polly (or any oil based finish) to get the color to pop again. Walnut is another quick color changer off the mill. Fresh sawn walnut is olive green! Quickly after milling(30-60 min) it is a nice chocolate brown.
> 
> Fbe is also a good one to discuss UV effects on wood....
> 
> Walnut is also a long term color changer...
> 
> Great info in the article. All woodworkers should have basic knowledge on the topic and your info is presented in terms that most can digest. Thanks for taking the time to write it and share with the group.


 
Thanks Greg. I've updated the article since you read it and now mention FBE and have added pics of purpleheart and a couple of others. I'm planning to add a pic of FBE but haven't taken the "after" pic yet.

So many people have mentioned walnut that I guess I'm going to have to add it. Left it off originally because although I've used a fair amount, I'm not familiar w/ the color change. Thanks for the info.


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## Mike Jones

Walnut's color change is unique. Where most wood gets darker with age or exposure to sunlight, walnut gets lighter, fades, bleaches, or whatever you want to call it. I have not found this to occur except with direct exposure to sunlight.


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## phinds

Mike Jones said:


> Walnut's color change is unique. Where most wood gets darker with age or exposure to sunlight, walnut gets lighter, fades, bleaches, or whatever you want to call it. I have not found this to occur except with direct exposure to sunlight.


 
That is hardly unique. I've already discussed in the article two woods that fade rather than getting darker. Those are redheart and aromatic red cedar (Eastern red cedar). The fading in those two is much more severe than walnut's.


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## rob3232

Walnut and cherry both develop a patina after ageing. (Out of direct sunlight)
In my humble opinion the patina (darker and more warm color) can not be duplicated?? 
Direct U.V. will bleach them both. Also, turn hard maple yellow. 
I'm no expert just my nickle


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## phinds

rob3232 said:


> Walnut and cherry both develop a patina after ageing. (Out of direct sunlight)
> In my humble opinion the patina (darker and more warm color) can not be duplicated??
> Direct U.V. will bleach them both. Also, turn hard maple yellow.
> I'm no expert just my nickle



I'm not experienced w/ the color change in walnut, but I absolutely agree w/ you on cherry and have said so both in the article and on the cherry page of my site.


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## barry richardson

Paul, please disregard, and don't flame me, if I repeat something, or it disagrees with something you have already said, here is my input; 
Color change tends to occur in wood primarily by two different processes, oxidation and photoreactivity. Oxidation seems to have the most effect on oily woods, darkening them. Desert ironwood, Cocobolo, Zirc, Bocote, and all the other rosewoods, lignum vitae, teak are some that come to mind. To my knowledge, Teak is the only oily wood that benefits in appearance from this, becoming a nice rich brown. All the others I'm aware of darken and loose their chatoyance over time, and eventually appear 'dead as a mullet' (excuse my technical terms). Desert ironwood is the most extreme of the oxygen reactive woods I am familiar with, it is interesting to observe the stages of oxidation in different pieces of diw, dead for different periods of time. It is much more like iron rusting than conventional wood decay. It progressively darkens, becomes brittle and looses it elasticity, and eventually turns to a black crumbly dirt-like material. I read a blurb on Gilmer Hardwoods' DIW page that says "The best colored material comes from dead trees/logs that may have lain on the desert floor for decades". This is nonsense, don't know where this story started but I have seen similar statements elsewhere. The longer it lays dead in the dessert, the more it oxidizes and the darker and less chatoyant it becomes.
On the other hand, many photoreactive woods tend to benefit from change, some already mentioned, i.e. cherry, the oaks, mesquite, African sumac, Carob, and probably several others. It was mentioned before about maple darkening which I think is important to note since it is such a widely used wood. Fresh cut (sapwood) is usually quite blond, but it turns golden brown with time, as a piece of antique maple furniture will show. Hmmm, about typed out, hey! lets look at some pictures! 
This is African Sumac. The bowl was made about a year ago, with a fresh cut piece of the same wood inside:



These pictures are of a mesquite piece with diw as trim. The color change may vary with the type of mesquite, but in Arizona, or Velvet Mesquite, like this one, it is significant, starts out kinda gray, but turns a nice rich red-brown. The ironwood on the other hand started out with nice color, but has dulled and darkened. I made this at least 5 years ago and don't recall the finish, but I think it was a light oil finish, then waxed. Had I used I used a finish that provide a better oxygen barrier like lacquer, the diw would have preserved better.


 


Paul, please use or discard as you see fit..


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## phinds

Barry, thank you for all that. I'll add that African sumac pic for sure and probably some of the other info as well. As I said in the article, I'm not trying to make a list of what happens to every single wood, just describe the kinds of color change that happens. Did the finish you used contribute anything to the color change on the African sumac or was that all due to the UV exposure?


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## barry richardson

phinds said:


> Barry, thank you for all that. I'll add that African sumac pic for sure and probably some of the other info as well. As I said in the article, I'm not trying to make a list of what happens to every single wood, just describe the kinds of color change that happens. Did the finish you used contribute anything to the color change on the African sumac or was that all due to the UV exposure?


Sumac change is all uv, unfinished wood turns the same color....


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## phinds

barry richardson said:


> Sumac change is all uv, unfinished wood turns the same color....



Thanks, Barry. I've just added the African sumac to both the web page and the color change article (and given you credit in both places)

By the way, I see a LOT of desert ironwood used as pistol grips. Do these deteriorate over time or does a good finish keep that from happening?


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## barry richardson

phinds said:


> Thanks, Barry. I've just added the African sumac to both the web page and the color change article (and given you credit in both places)
> 
> By the way, I see a LOT of desert ironwood used as pistol grips. Do these deteriorate over time or does a good finish keep that from happening?


I'm certain they will darken over time, but a good finish will slow it down. They wont deteriorate otherwise...


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