So much for testing “freshly cut” wood. Seems like any external additive would alter the test conditions. Chuck
Sunlight aging
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Right, good point. You'd have to let the color change take place and then sand off the shellac and hope the color change goes deep enough that it doesn't come off too. Porous wood would be a problem.
Simple vacuum system for food would work fine for this
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- #44
I have something like that. I will put this in the to-do list of experiments...
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- #45
Back to this cherry...
We measured chatoyance on 6 samples like the one on top and on 4 like the one on the bottom. Then we sanded them and repeated the test.
Impressively, chatoyance survives weathering and it is even highlighted by it!
This is one sample before and after sanding:
Before sanding
After sanding
[more details here: https://www.chatometry.com/case-studies/sunlight-weather/sunlight-weather-exposure-on-sweet-cherry/ ]
We measured chatoyance on 6 samples like the one on top and on 4 like the one on the bottom. Then we sanded them and repeated the test.
Impressively, chatoyance survives weathering and it is even highlighted by it!
This is one sample before and after sanding:
Before sanding
After sanding
[more details here: https://www.chatometry.com/case-studies/sunlight-weather/sunlight-weather-exposure-on-sweet-cherry/ ]
Nice
I used to know a guy who made rustic picture frames. He'd come into the yard and buy 10-15 1x4 and 1x6 ( I don't remember lengths) rough cedar every month. (He'd also weed out all the split or damaged stuff too at a discount. He'd take it and lay it out on his barn roof. He'd make his frames out of the boards he'd pull down making room for the new stuff. He'd let it sit up there for about a year. This was in Freer Texas and nobody built privacy fences. The rough cedar we sold was mostly for facia. Around here a guy can get all the weathered fencing he want for the hauling.
Alan
Alan
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- #48
Thanks, this is interesting. I will pay more attention to weathered wood from now on!
So this little end table had caning that failed. I planned to redo it. Well, after sitting outside for 8 years, I decided to convert to BTU's. 'American Black walnut' slightly weathered. Here are a few pieces as I deconstruct.
Still good inside.
Here is a piece of walnut that was stored in the attic above a garage. House was built in 1990's, no clue how long it has been there. Cold in the winter and likely very hot in the summer. The wood looks kind of orange / brown...
Still good inside.
Here is a piece of walnut that was stored in the attic above a garage. House was built in 1990's, no clue how long it has been there. Cold in the winter and likely very hot in the summer. The wood looks kind of orange / brown...
Last edited:
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- #50
So gray is definitely related to weathering.
I have a cumaru outdoor table which turned gray after 2-3 years; I followed somebody's suggestion and applied some sort of "teak oil" this summer (no sanding at all), and I was amazed at how it went back to brown!
I have a cumaru outdoor table which turned gray after 2-3 years; I followed somebody's suggestion and applied some sort of "teak oil" this summer (no sanding at all), and I was amazed at how it went back to brown!
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- #51
Back to our aged maples samples...
I found three more boards from the same company and compared their color to these samples (photos below).
My personal conclusion is that those samples above received a lot of sunlight, but that's it. I will ask the company as a double check, but I can't really see why they would paint a leftover board as their business really is veneer.
I found three more boards from the same company and compared their color to these samples (photos below).
My personal conclusion is that those samples above received a lot of sunlight, but that's it. I will ask the company as a double check, but I can't really see why they would paint a leftover board as their business really is veneer.
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- #52
We ran chatoyance tests on these nice "aged" maple samples. Shortly, it appears that sunlight exposure significantly increased chatoyance (from PZC~13 to PZC~20)
As received, front:
As received, back:
More details here:
As received, front:
As received, back:
More details here:
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- #53
We had a bit of discussion on this.
We measured chatoyance and brightness on 3 samples straight after sanding and then after about 3 weeks (air exposure only - no light)
The average of 9 measurements says:
7% reduction in brightness
0.0 PZC change in chatoyance (practically no change)
Below an example, just after sanding and then after 26 days (sample from @2feathers Creative Making , whom I thank)
Nice stuff, but definitely exotic here :(
Good test Paolo. I must be wrong about it being the air that does in ERC and it's all (or almost all) the UV. Good info. Thanks.
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- #55
I don't know, my sample was dry. Maybe something different happens on fresh cut wood, as you mentioned. I am now testing an elm piece, from very fresh (few hours after tree felling, few minutes after log splitting) to fully dry. In the first few hours I noticed an evident darkening of the wood surface, and no light was involved... More details when I finish the tests.
Well, the change is definitely most obvious in freshly cut wood. It goes from a brilliant purple to much duller and over a long time it fades to a dull tan
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- #57
I guess I will never see fresh cut ERC here
But if I stumble on some London Plane I will surely get it tested!
I see that this is a bit older thread but both interesting and timely for me. I have a bit of a unique perspective to lend, for what it's worth. Given my carvings are done from green wood as well as using very traditional methods that I feel give me a little closer relationship to my work and material, I have the opportunity/time to see things as I'm carving. Just recently I made some notes in my Greenwood Carving thread regarding the properties of the Black Locust I was working with. I finished that and moved to another carving with a piece of Almond and have been pondering the differences I'm observing, stuff I've been making note of for quite some time and cataloging for a rainy day. It's been raining a lot here lately...
I've noted from the beginning when I carve. wood that is green, when you take a slice of wood, exposing fresh, green wood, the color is bright and vibrant as if you just oiled a dry piece. The Black Cherry I've carved lots of would stay looking nice for a bit but if I went back over an area a bit of time later you would notice it had lost some of it's vibrance restored by the fresh cut. This goes on throughout the roughing phase until I let it dry, then make finish cuts which restores the vibrance and gives the wood a polished appearance, better then you can get from any sanding. I came to the conclusion early on that there was oxidation at play. Also the dry wood, being harder, takes a smoother cut as opposed to the somewhat fuzzy surface left when cutting it green, even with a very sharp knife. Black Walnut very similar, Birch maybe a little more dramatic but the level of oxidation always seemed to be dependent on the moisture level.
When I use the drawknife to clean the end grain for identification under a loupe, I've noted that some woods haze over with oxidation very fast while others are very gradual and mostly it is moisture level that is the primary factor.
Recently carving the Black Locust I made several observations as I was working and ended the post about that with some discussion about some properties that appear somewhat unique. The Black Locust starts out with very little moisture content to begin with and when cutting into it there is very little of that "fresh cut" color change. Similarly, very little if any change going back over it after it's dried, very little oxidation... Interesting to me was that Black Locust is a well know very durable wood, virtually impervious to rotting. I think a primary factor in it's durability is the presence of significant amounts of silica, which may also be a factor in it's starting low moisture content. I'm sure silica also has it's own unique optical properties but that may be a tangent too far. But... now this thread got me thinking. I know, Danger Will Robinson!!! The Almond I'm presently working on was sopping wet green. Very hard wood, very hard but green it's quite pliable to cut through with a knife. When I split the log, it had really beautiful color inside and working it I was very enthusiastic but noted right away, slice a shaving, revealing extraordinary color but it would oxidize over to near grey almost instantly. As it's been drying more,, reworking sections shows the color then it hazes over again, not quite as bad but still very noticeable. Also noticeable is that it is drying much more slowly than other woods. I started thinking about the moisture and the lack of durability that the Locust has and the silica... So, what minerals does Almond have and how much may the evaporation of water at the surface, depositing minerals that were in solution, play into the hazing over/oxidation effect? Similar question goes for sugar content. Each also having an effect on optical properties. Even more so, how much is the actual wood oxidizing and how much is the minerals deposited on the surface that are oxidizing?
The preceding has been the rantings of a lunatic mind, that is running out of break time. Have fun chewing on all of this. I'll see if I can post some pictures or video of the effects I'm talking about.
I've noted from the beginning when I carve. wood that is green, when you take a slice of wood, exposing fresh, green wood, the color is bright and vibrant as if you just oiled a dry piece. The Black Cherry I've carved lots of would stay looking nice for a bit but if I went back over an area a bit of time later you would notice it had lost some of it's vibrance restored by the fresh cut. This goes on throughout the roughing phase until I let it dry, then make finish cuts which restores the vibrance and gives the wood a polished appearance, better then you can get from any sanding. I came to the conclusion early on that there was oxidation at play. Also the dry wood, being harder, takes a smoother cut as opposed to the somewhat fuzzy surface left when cutting it green, even with a very sharp knife. Black Walnut very similar, Birch maybe a little more dramatic but the level of oxidation always seemed to be dependent on the moisture level.
When I use the drawknife to clean the end grain for identification under a loupe, I've noted that some woods haze over with oxidation very fast while others are very gradual and mostly it is moisture level that is the primary factor.
Recently carving the Black Locust I made several observations as I was working and ended the post about that with some discussion about some properties that appear somewhat unique. The Black Locust starts out with very little moisture content to begin with and when cutting into it there is very little of that "fresh cut" color change. Similarly, very little if any change going back over it after it's dried, very little oxidation... Interesting to me was that Black Locust is a well know very durable wood, virtually impervious to rotting. I think a primary factor in it's durability is the presence of significant amounts of silica, which may also be a factor in it's starting low moisture content. I'm sure silica also has it's own unique optical properties but that may be a tangent too far. But... now this thread got me thinking. I know, Danger Will Robinson!!! The Almond I'm presently working on was sopping wet green. Very hard wood, very hard but green it's quite pliable to cut through with a knife. When I split the log, it had really beautiful color inside and working it I was very enthusiastic but noted right away, slice a shaving, revealing extraordinary color but it would oxidize over to near grey almost instantly. As it's been drying more,, reworking sections shows the color then it hazes over again, not quite as bad but still very noticeable. Also noticeable is that it is drying much more slowly than other woods. I started thinking about the moisture and the lack of durability that the Locust has and the silica... So, what minerals does Almond have and how much may the evaporation of water at the surface, depositing minerals that were in solution, play into the hazing over/oxidation effect? Similar question goes for sugar content. Each also having an effect on optical properties. Even more so, how much is the actual wood oxidizing and how much is the minerals deposited on the surface that are oxidizing?
The preceding has been the rantings of a lunatic mind, that is running out of break time. Have fun chewing on all of this. I'll see if I can post some pictures or video of the effects I'm talking about.
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- #59
Very interesting... But a very complex subject I guess. Maybe the book "wood and cellulosic chemistry" can tell something.
Unfortunately, I am not familiar with fresh wood. I only cut some elm, which seems light brown when just cut, and then it quickly oxidizes (?) to medium dark brown.
However, I am very curious about this:
I ask because I hear that a very sharp cutting tool provides a better finish (and chatoyance) than any sanding. This is confirmed by some of our tests on veneer as received and then sanded to 1500 grit ( https://www.chatometry.com/case-studies/raw-veneer-vs-fine-sanded/ ).
Unfortunately, I am not familiar with fresh wood. I only cut some elm, which seems light brown when just cut, and then it quickly oxidizes (?) to medium dark brown.
However, I am very curious about this:
Is it easy to achieve this result? Do you sharpen your tools in a specific way? Is it easy for someone who never did it?
I ask because I hear that a very sharp cutting tool provides a better finish (and chatoyance) than any sanding. This is confirmed by some of our tests on veneer as received and then sanded to 1500 grit ( https://www.chatometry.com/case-studies/raw-veneer-vs-fine-sanded/ ).
Your "paragraph" (exposition actually) is too long to chew on.