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IR/Heat treatment is a bit different than UV exposure and so can result in different coloring effects and mechanical changes.

Basically, the various compounds in the wood are in a set of slow transitions from one set of compounds into another. The general term for these transitions is "thermal aging". When you heat the wood, it accelerates these transitions. Like UV exposure, the rate of the change is proportional to the density of the initial set of compounds. So thermal aging proceeds rapidly at first, then gradually slows down to a crawl as more of the initial compounds transition to the new set of compounds.

The availability of moisture in the air is an important component of many of these transitions during the natural aging process. So if one is trying to accelerate the aging by increasing the temperature, some control of moisture content is needed to reproduce the effects of natural aging.

There is a limit to how high the temperature can be before new chemical processes are triggered that would not normally occur during natural aging. For wood, it seems to be as one approaches the boiling point of water (100C). This is not a comment on whether these changes are good or bad for violin making. I just want to point out that you would be entering a realm beyond accelerated natural aging.

So many variables to juggle.

 

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I wanted to mention that I have had luck, after reading here, misting the instrument a couple times per day with filtered water. My light box is fairly modest, but this seems to have kicked things up a notch. I seem to be getting color faster this way. Possibly it's psychosomatic, but I think it's helping. 

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7 hours ago, JacksonMaberry said:

I wanted to mention that I have had luck, after reading here, misting the instrument a couple times per day with filtered water. My light box is fairly modest, but this seems to have kicked things up a notch. I seem to be getting color faster this way. Possibly it's psychosomatic, but I think it's helping. 

UV radiation breaks down chemical bonds in the surface of the wood and creates free radicals (compounds with a net charge that are very reactive). These can then react with other chemicals to create chromophore compounds (chemicals that can absorb photons and then release them in the visible light range). Water is well known to accelerate these reactions.

In some woods, these chemical reactions can continue and cause the chromophore compounds to eventually degrade, thus giving a bleaching effect. I am not sure how relevant this is for spruce and maple commonly used in violins, but as you experiment realize that more (UV exposure or water) might not necessarily be better.

Also, UV radiation does not penetrate very deeply into wood, so the creation of the chromophores is more a surface phenomenon.

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On 6/2/2018 at 11:06 AM, Evan Smith said:

Exactly,

Misting with water makes a beautiful golden natural color at around 100F,

Warning, all of my wood has been repeatedly soaked and dried, it does make a big difference and is worth the extra trouble,,,,,,, so a little heat and water are of no concern to me, be careful, learning curves are not fun.

Or a faster method is to spritz a bit of dilute tannic acid in water on the fiddle exposed to the sun for a day, ,,,a bit of Osage orange wood boiled down and  the tannic acid will make a nice warm golden color for a ground. Osage orange is sold all over because it is a great dye, but it is insanely expensive at times,,, it grows like a weed throughout the Midwest, in Oklahoma and Texas the ranchers will pay you to cut it down and take it because it gets in the way of their grazing cattle. I bet not telling has some in her back yard.

In fact just boiling up most woods will give a color to wood when re applied using 2 parts hydrogen and 1 part oxygen, just concentrate it to make it stronger. Different shades can be handy to even up the natural color variations, depends on how much one wants to futz around.

Sure don't want to look like a North Dakota Norwegian girl in Jamaica in January.

Evan Viking by Marriage

I prepped some osage orange in K2CO3 (potassium carbonate) and got this color.  I put turpentine down on the spruce before applying (left 20180615_172346.thumb.jpg.ec91192639a56410730c0791bbc9512c.jpg).  I see a greenish tinge.

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1 hour ago, Julian Cossmann Cooke said:

I prepped some osage orange in K2CO3 (potassium carbonate) and got this color.  I put turpentine down on the spruce before applying (left 20180615_172346.thumb.jpg.ec91192639a56410730c0791bbc9512c.jpg).  I see a greenish tinge.

Doesn't look bad, Julian, and I suspect it will mellow a lot once dried and with some UV exposure. So far, the best looking vegetable ground color I have seen was lpr's cape aloe, on his bench page I think. 

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13 hours ago, JacksonMaberry said:

Doesn't look bad, Julian, and I suspect it will mellow a lot once dried and with some UV exposure. So far, the best looking vegetable ground color I have seen was lpr's cape aloe, on his bench page I think. 

I've tried to get cape aloe but without success.  Reportedly used by Craske in his varnish and I am making a Craske model viola.  Have to try to reach lpr.

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1 hour ago, Julian Cossmann Cooke said:

I've tried to get cape aloe but without success.  Reportedly used by Craske in his varnish and I am making a Craske model viola.  Have to try to reach lpr.

Hi Julian,

You can find it on Amazon. Be aware there are different parts of the plant that are available. I used Aloe Ferox Bitter Extract. Somewhere out there on the interweb is an article that explains what the different parts of the plant are and how they are used.

I bought a small jar of the extract and mixed it with vodka to make a very concentrated solution. You will have to experiment with this stuff because at first it has a greenish tint.

But after some time (weeks)in the sun it turns into a lovely golden brown. At least it did on the maple and spruce I tested.

I applied it straight on the wood and got the best results. I also tried applying it after a light sizing with gelatin and the color did not turn like the raw wood.

As  I recall the bitter extract is the actual sap from the plant. I know they sell whole leaf powder and I have some of that too but haven't experimented with it.

I'll post this info on the sun tanning thread for others who may want to experiment with it.

Best of Luck with it!

https://www.amazon.com/Aloe-Ferox-Bitter-Extract/dp/B00BEGJ91U

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32 minutes ago, Julian Cossmann Cooke said:

Interesting resource available through libraries and ILL (http://www.worldcat.org/search?qt=worldcat_org_bks&q=the+art+of+mordanting+and+staining&fq=dt%3Abks) : The Art of Mordanting and Staining, William Zimmerman.

How do you get books from worldcat?  I've occasionally have gotten books via interlibrary loan.  Most of the time I get nothing.  Maybe I'm just interested in books that are not available for ILL.  This book is actually cheap ($18).  Must be because it's not a violin specific book.  :)  I finally bit the bullet and bought "Violin Varnish and Coloration" by Zemitis just yesterday.  Not so cheap. <_<

-Jim

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1 hour ago, Jim Bress said:

How do you get books from worldcat?  I've occasionally have gotten books via interlibrary loan.  Most of the time I get nothing.  Maybe I'm just interested in books that are not available for ILL.  This book is actually cheap ($18).  Must be because it's not a violin specific book.  :)  I finally bit the bullet and bought "Violin Varnish and Coloration" by Zemitis just yesterday.  Not so cheap. <_<

-Jim

Worldcat just lists where the holdings are -- which libraries.  I got this in ILL when I was in SLC.  

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7 hours ago, uguntde said:

Does the tanned layer go deeper if one uses a high power (1000W) lamp?

With that kind of power, you have an oven... and you could bake it brown all the way thru.

However, UV is UV, and more power just means it will do whatever it's doing faster.  It won't go any deeper than the equivalent power x time of a lower power lamp.

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On 6/2/2018 at 3:17 PM, fiddlecollector said:

I tried dozens of methods but one that stuck in my mind was a simple organic solution applied and then several hours of uv tube light (just overnight if i remember right).

 

 

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Effect on maple with same treatment

 

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With some varnish

 

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What is that organic solution ?

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