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Tintura veneziana


H.R.Fisher
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Michael when you say tannen what chemical is this? I have some tannic acid in the shop but frankly don't remember why although I think it was used before applying potassium dichromate. Also have used strong tea before Khali on necks. I have never seen the "turning green" result from Dichromate using this method. Necks I made thirty five years ago still seem to have a cinnamon brown to red color except where they have actually been allowed to absorb sweat which looks dirty and gray. I would be interested in satisfactory ways to achieve a grayer color to the wood especially in the case of large scale repairs such as a new top or new scroll which some times does happen. As far as I can tell it is really very difficult to make wood look old with the varnish alone requiring some sort of oxidation underneath.

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Re: Tintura, thanks to Nick and AD for sharing their experiences! It's especially interesting to me, because I just slap it on the bare white wood, give it a couple hours in the lightbox, and then repeat until I get where I want. Never have tanned it first. I'm glad that it seems to play nice for folks even with different approaches!

 

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Here is a shot from today. Unlike AD and Nick Allen, I don't tan the instrument before applying Tintura. I just brush it on, give it a few hours in the light box, then repeat. I typically end up doing three coats. I don't generally bother pre-wetting with water, or turpentine, but it might be beneficial on softer spruce. In my experience, any unevenness would disappear under my ground, if present at all. It is, after all, not a dye, but an oxidizer. 

From left to right - 1) belly treated with three coats of Tintura, exposed to UV between coats, totalling about 8 hours of exposure. 2) back not treated with Tintura, but exposed to UV for the same duration. 3) piece of wood from the same maple tree, not treated and not exposed to any UV. 

There are two versions of the same photo - one taken under Philips 60w equivalent daylight LED with stated 90CRI with OnePlus 9 phone camera, the other edited for a match in the color I see here with my eyes. Given the difference in everyone's screens, I understand it's a challenge for photos, raw or corrected, to say something meaningful. It's cloudy here today, but if anyone would like I can take a similar photo outdoors with natural light. 

 

IMG20220928082319~2.jpg

IMG20220928082319~3.jpg

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On 9/28/2022 at 11:47 AM, JacksonMaberry said:

Outdoor shot, unmodified. Nice diffuse light through the clouds today.

IMG20220928084109~2.jpg

While that looks nice, and is perfect for straight varnishing, it looks too warm for heavy antiquing to me. But I suppose this product isn't geared towards that approach, anyways. Do you think that there is a way to push the tone in a particular direction without fouling the job? 

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22 minutes ago, Nick Allen said:

While that looks nice, and is perfect for straight varnishing, it looks too warm for heavy antiquing to me. But I suppose this product isn't geared towards that approach, anyways. Do you think that there is a way to push the tone in a particular direction without fouling the job? 

Thanks for this, Nick! I'd agree with your point here wholeheartedly. I admit that I have designed all of the sauces with my own aesthetic aims at the forefront, and not being an antiquer, I think that shows. However, I do want to be able to provide tools for luths of all stripes to enjoy.

I think the Tintura in particular can be more suitable to your needs if less is used. In the photos above I have gone hard and fast - three applications in a day, but using less and doing so in tandem with more UV can get you closer to what I think I understand you are seeking. Without knowing more about your specific goals I hesitate to ramble further, but hit me up on insta or give me a call if you'd like to talk more specifically about what your vision is and if anything I make could be useful to you. If it's not, I'd rather you spent your time or money on something else, and I might be able to direct you to where to find that. I have tried so many things commercial or otherwise, so I have some ideas about what else is out there.

I think all of you can agree that this work is some of the most personal out there, and that's what I love most about it. I have no illusions about where my tools fit into the continuum of the materia - they're only an option, not a necessity.

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On 9/28/2022 at 8:47 AM, JacksonMaberry said:

Outdoor shot, unmodified. Nice diffuse light through the clouds today.

IMG20220928084109~2.jpg

The color looks very much the same as Old Wood's primer which to me is a little too orange. When I used OW's primer I suspected it had some dye mixed with an oxidizer because of the orangey color. 

Are you adding any type of coloring agent to the oxidizer? Do you get the same color on maple?

I prefer more yellow/gold in my ground. Nice blotch free application. 

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25 minutes ago, charliemaine said:

The color looks very much the same as Old Wood's primer which to me is a little too orange. When I used OW's primer I suspected it had some dye mixed with an oxidizer because of the orangey color. 

Are you adding any type of coloring agent to the oxidizer? Do you get the same color on maple?

I prefer more yellow/gold in my ground. Nice blotch free application. 

I have a bottle of OW primer, from the smell of it alone I know it's not like what I'm making. I can't say what their composition is other than what I can can guess at with my nose, eyes, and... Well I may have tasted a drop of it, for science. I am still unclear as to whether they include dyes, but I do not. When you brush Tintura on white wood, it looks white still until the oxidation has taken hold in UV.

With it in my hands, I am not seeing the oranginess, but rather a heavy gold with a bit of cinnamon. Like I suggested to Nick, if you were to use less than I have, it would hew closer to yellow. You can mellow most oxidation color in wood towards silver with a very weak solution (~1%) of potassium carbonate. 

Further, when I ground over the primed wood, the change in optics shifts the perception of color to what I imagine you'd enjoy more, given your bench thread. I'll post photos of fully grounded fiddles when they're ready. 

I do enjoy how easy this stuff is to apply. I just slap it on willy nilly with a soft brush, going over the same spots all the time, and it doesn't blotch. I can't do that with anything containing dyes.

Every stick reacts differently as in all things, but I'm general the behavior of the spruce and the maple is extremely close. I might do one fewer coats on the maple to make it align with the spruce, depending on the sticks. 

Great questions, keep them coming!

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On 9/22/2022 at 4:53 AM, nathan slobodkin said:

Michael when you say tannen what chemical is this? I have some tannic acid in the shop but frankly don't remember why although I think it was used before applying potassium dichromate. Also have used strong tea before Khali on necks. I have never seen the "turning green" result from Dichromate using this method. Necks I made thirty five years ago still seem to have a cinnamon brown to red color except where they have actually been allowed to absorb sweat which looks dirty and gray. I would be interested in satisfactory ways to achieve a grayer color to the wood especially in the case of large scale repairs such as a new top or new scroll which some times does happen. As far as I can tell it is really very difficult to make wood look old with the varnish alone requiring some sort of oxidation underneath.

to make new wood look "grey and weathered" make an oak gall, water, steel wool concoction and allow it to sit for about a week and a half to two, which, less a thickener such as ground eggshell is basically iron gall ink, using practice wood, apply anywhere from 3 to 30? coats, treating it as if you wet the wood with water, allowing for adequate dry time in between coats, on wood you will see 3 coats impart a light grey cast, 10 coats gets you the "grey redwood deck" level and once you get into high teens and 20's you will get jet black eventually.

it will raise the grain slightly but can be smoothed down /sealed in a variety of ways

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15 hours ago, jezzupe said:

to make new wood look "grey and weathered" make an oak gall, water, steel wool concoction and allow it to sit for about a week and a half to two, which, less a thickener such as ground eggshell is basically iron gall ink, using practice wood, apply anywhere from 3 to 30? coats, treating it as if you wet the wood with water, allowing for adequate dry time in between coats, on wood you will see 3 coats impart a light grey cast, 10 coats gets you the "grey redwood deck" level and once you get into high teens and 20's you will get jet black eventually.

it will raise the grain slightly but can be smoothed down /sealed in a variety of ways

I like this idea. Would you happen to have the recipe with quantities on hand? Thanks!

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33 minutes ago, JacksonMaberry said:

Personally I'd be a bit concerned about the reactivity of the iron acetates formed, but not having firsthand experience with it, I don't want to make any firm claims. Definitely sounds like it could be a useful tool in the kit.

My neighbor asked me about wood staining methods for his new built wooden hut. I told him about the iron/acetate solution, and he used it on the outside. Was pretty disappointed, because there was almost no visible effect. One year later, the color turned to a really dark grey.

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Just now, Michael Szyper said:

My neighbor asked me about wood staining methods for his new built wooden hut. I told him about the iron/acetate solution, and he used it on the outside. Was pretty disappointed, because there was almost no visible effect. One year later, the color turned to a really dark grey.

That sounds about right. Iron gall ink is typically ferrous sulfate and tannic acid in aqueous soln, therefore ferrous tannate complex. Oxidation converts this to the ferric state (giving ferric tannate), which is not water soluble, darkening and giving your color. What Jez is describing is giving a mixture of ferric tannate and acetate.

Once in the ferric state and presenting the desired color, it's not guaranteed to stay that way. Under the right conditions, it can be reduced again to the ferrous state and your color no longer what you wanted. 

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20 hours ago, Michael Szyper said:

My neighbor asked me about wood staining methods for his new built wooden hut. I told him about the iron/acetate solution, and he used it on the outside. Was pretty disappointed, because there was almost no visible effect. One year later, the color turned to a really dark grey.

 

19 hours ago, JacksonMaberry said:

That sounds about right. Iron gall ink is typically ferrous sulfate and tannic acid in aqueous soln, therefore ferrous tannate complex. Oxidation converts this to the ferric state (giving ferric tannate), which is not water soluble, darkening and giving your color. What Jez is describing is giving a mixture of ferric tannate and acetate.

Once in the ferric state and presenting the desired color, it's not guaranteed to stay that way. Under the right conditions, it can be reduced again to the ferrous state and your color no longer what you wanted. 

I have heard of some who apply an iron acetate solution after sodium nitrite on bare wood, that I have never felt like trying for fear that the reaction would not stop. Do you have an idea of what the reaction between nitrite and iron acetate could be?

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11 minutes ago, Davide Sora said:

 

I have heard of some who apply an iron acetate solution after sodium nitrite on bare wood, that I have never felt like trying for fear that the reaction would not stop. Do you have an idea of what the reaction between nitrite and iron acetate could be?

I am not entirely sure. I hope that a more qualified chemist will chime in on that, I am curious as well. 

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