Michael Darnton Posted October 16, 2022 Report Share Posted October 16, 2022 On 6/13/2018 at 11:32 PM, 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. What you are doing here: water + UV = nitric acid being generated on the surface of the wood. The thing to watch out for here is that after a certain point the reaction speeds up to the point where the water dots of mist on the wood can immediately form acid and the wood, top particularly, starts to develop tiny black burn freckles. I have a friend who used this method and I have not seen any ill effect in the long term--it's not enough acid to soak in and damage the wood deeply. As far as I know so far. He's been doing it for 40 years. Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 5 minutes ago, Michael Darnton said: What you are doing here: water + UV = nitric acid being generated on the surface of the wood. The thing to watch out for here is that after a certain point the reaction speeds up to the point where the water dots of mist on the wood can immediately form acid and the wood, top particularly, starts to develop tiny black burn freckles. I have a friend who used this method and I have not seen any ill effect in the long term--it's not enough acid to soak in and damage the wood deeply. As far as I know so far. He's been doing it for 40 years. Never saw that, but I haven't done that in quite a while. I have an atomizer in a basin of distilled water at the bottom of the lightbox now, controlled by a hygrostat to maintain a humidity of 40-45% RH in the box while it's running. Gives me the same results, which is nice, without pausing to mist. Set it and forget it. Finely divided water in the cabinet also offers ready oxygen for varnish to uptake in curing. The chemistry of your message doesn't quite make sense, for the record. Water + UV =\= HNO₃, or HNO2 for that matter. You'd have to add a nitrogen source, and then explain how the nitrogen enters the reaction. Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 Michael - retraction and apology. Now that I am awake, I see what you're saying. UV does generate nitric oxide, which interacts with water present to form nitrous acid. Like nitric, nitrous is an oxidizing acid and will of course do some oxidizing. That's what's happening, as you suggest, with the water. This oxidizes (tans) the wood and also oxidizes (cures) the varnish. Quote Link to comment Share on other sites More sharing options...
Davide Sora Posted October 16, 2022 Report Share Posted October 16, 2022 5 minutes ago, JacksonMaberry said: Michael - retraction and apology. Now that I am awake, I see what you're saying. UV does generate nitric oxide, which interacts with water present to form nitrous acid. Like nitric, nitrous is an oxidizing acid and will of course do some oxidizing. That's what's happening, as you suggest, with the water. This oxidizes (tans) the wood and also oxidizes (cures) the varnish. Yep, I was going to write it. However, nitrous acid would still form even without additional water, simply with oxygen and moisture present in the air, it seems to be the main contributor to UV tanning, as the late Koen Padding states in his article on the use of UV box. He actually talks about the formation of nitrous oxygen, which forms an acid inside the wood that causes tanning: VSAP-K.Padding-UV.Light.pdf Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 19 minutes ago, Davide Sora said: Yep, I was going to write it. However, nitrous acid would still form even without additional water, simply with oxygen and moisture present in the air, it seems to be the main contributor to UV tanning, as the late Koen Padding states in his article on the use of UV box. He actually talks about the formation of nitrous oxygen, which forms an acid inside the wood that causes tanning: VSAP-K.Padding-UV.Light.pdf 228.08 kB · 1 download Yes, I forgot about that article! Thank you! I am unfortunately prone to posting before coffee, so apologies again to Michael. Yes, the Nitrous will form regardless, but more of it and more quickly with moisture. This is a key factor in the curing of urushiol lacquers. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted October 16, 2022 Report Share Posted October 16, 2022 I have understood/heard that the water converts nitrous acid into nitric, but the chemistry to confirm that is beyond me. The relevant reactions are here:. https://en.m.wikipedia.org/wiki/Nitrous_acid Quote Link to comment Share on other sites More sharing options...
Davide Sora Posted October 16, 2022 Report Share Posted October 16, 2022 26 minutes ago, Michael Darnton said: I have understood/heard that the water converts nitrous acid into nitric, but the chemistry to confirm that is beyond me. The relevant reactions are here:. https://en.m.wikipedia.org/wiki/Nitrous_acid Is beyond me too, trying to understand something from all these formulas and reactions only causes me a headache Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 33 minutes ago, Michael Darnton said: I have understood/heard that the water converts nitrous acid into nitric, but the chemistry to confirm that is beyond me. The relevant reactions are here:. https://en.m.wikipedia.org/wiki/Nitrous_acid It can and does in some situations, as the article outlines. Whether it does or not here is irrelevant, as both are oxidizing acids and will do the work, hence people using both nitrates (salts of nitric acid) and nitrites (salts of nitrous acid) to oxidize wood and other things. Non chemists like us don't have to understand it, it just works. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted October 16, 2022 Report Share Posted October 16, 2022 What might make it interesting to you is that in my experience these different methods have their own characteristic looks and their own associated problems. Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 7 minutes ago, Michael Darnton said: What might make it interesting to you is that in my experience these different methods have their own characteristic looks and their own associated problems. Same Quote Link to comment Share on other sites More sharing options...
John Harte Posted October 16, 2022 Report Share Posted October 16, 2022 1 hour ago, Michael Darnton said: What might make it interesting to you is that in my experience these different methods have their own characteristic looks and their own associated problems. Michael, I am very interested in hearing more if you are willing to share. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted October 16, 2022 Report Share Posted October 16, 2022 It's just a color difference and how they go wrong. Nothing important, but visible. I don't use either one now because the depth of color I like is flirting with danger. :-) Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 On the last few instruments, I've enjoyed the results from saturating the finished instrument in a blend of Tang and kerosene. Then I set it on fire with a crack torch, but you have to be really careful not to let it burn more than 3.6 percent, or about 0.81 seconds, and you need to make sure it burns evenly. Stradivari didn't have Tang, but he would have used it if it were available. He probably used ordinary orange juice. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted October 16, 2022 Report Share Posted October 16, 2022 I've got a stash of 400 year old Tang and you can't have any. :-P Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 16, 2022 Report Share Posted October 16, 2022 50 minutes ago, Michael Darnton said: I've got a stash of 400 year old Tang and you can't have any. :-P You cruel, cruel sonofagun Quote Link to comment Share on other sites More sharing options...
John Harte Posted October 17, 2022 Report Share Posted October 17, 2022 2 hours ago, Michael Darnton said: It's just a color difference and how they go wrong. Nothing important, but visible. I don't use either one now because the depth of color I like is flirting with danger. :-) Thank you Michael. Quote Link to comment Share on other sites More sharing options...
jordanmcdowell15 Posted October 17, 2022 Report Share Posted October 17, 2022 2 hours ago, JacksonMaberry said: On the last few instruments, I've enjoyed the results from saturating the finished instrument in a blend of Tang and kerosene. Then I set it on fire with a crack torch, but you have to be really careful not to let it burn more than 3.6 percent, or about 0.81 seconds, and you need to make sure it burns evenly. Stradivari didn't have Tang, but he would have used it if it were available. He probably used ordinary orange juice. What is tang? Can't find it with Google search unless you're talking about the orange drink. But since Michael has a 400 year old batch, I'm guessing that ain't it.... I almost set my fiddle on fire yesterday. Not really a varnishing exercise... More revenge for not wanting to except it's new sound post. Anyhow, how do you put the fire out quickly? I've heard sand(oded kishony) but I don't know the details. Quote Link to comment Share on other sites More sharing options...
JacksonMaberry Posted October 17, 2022 Report Share Posted October 17, 2022 39 minutes ago, jordanmcdowell15 said: What is tang? Can't find it with Google search unless you're talking about the orange drink. But since Michael has a 400 year old batch, I'm guessing that ain't it.... I almost set my fiddle on fire yesterday. Not really a varnishing exercise... More revenge for not wanting to except it's new sound post. Anyhow, how do you put the fire out quickly? I've heard sand(oded kishony) but I don't know the details. I apologize, but my post was purely silliness. Haha! Quote Link to comment Share on other sites More sharing options...
Dr. Mark Posted October 17, 2022 Report Share Posted October 17, 2022 On 6/15/2018 at 6:56 PM, Julian Cossmann Cooke said: I prepped some osage orange in K2CO3 (potassium carbonate) and got this color. The above was posted awhile ago, and although (judging by the lack of discussion) it's likely of no interest I concocted some bodarc stain in plain water last spring as a dye and applied to a new violin over water, but the top split while drying the varnish so I had to replace it. The stain is lighter than the images in the above post, but does have a greenish tinge that can be seen in sunlight. I like the appearance on the maple enough that I've been debating whether to bother with color varnish since the seal and ground varnish remove the green tinge. Bodarc is also supposed to darken over time so I'll see what happens Quote Link to comment Share on other sites More sharing options...
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