FiddleMkr Posted August 10 Report Share Posted August 10 One of the most recent threads got to the topic of linseed oil as a ground. The general consensus (i think) was no. That is oil is a dampener and you don’t want that on a violin plate. However I have read that linseed oil can be used successfully as a ground, plus it gives the wood a base colour and highlights annual rings. It does “dry” after two weeks (or maybe longer?), and on my sample fiddle it is safe to say that after 22 years (anyway) it is dry enough to apply varnish on top. Does anyone know how long it takes for linseed oil to dry enough for oil varnish to be applied safely? Or since oil varnish has a linseed oil base, can oil varnish EVER be applied on top safely? OR can spirit varnish be applied to a linseed oil ground? I don’t want to muddy up the topic too much, but besides the one fiddle, I have shied away from oil grounds, because I was instructed to do so. However, the “primer” I was instructed to use is basically a clear oil varnish. So, the instructions were “don’t put oil on the bare wood, whatever you do, but instead put this primer on there, which is clear oil varnish.” The only thing I can figure is that the varnish must dry fast enough that it seals the wood, and oil varnish is different enough from just oil that it’s not a dampener? Is this correct? Quote Link to comment Share on other sites More sharing options...
Dr. Mark Posted August 10 Report Share Posted August 10 There seems to be a lack of conclusive data about whether there is or is not a non-oil based sealer between the wood and the ground on Strad's fiddles, so do you want to discuss ground or sealer? Evidence of a drying oil shows up on many, perhaps all, analytic spectra of Strad varnishes. Since restorers as a rule use a reversible medium I believe and some effort is made to get good samples, it's likely the oil is original. I think Mr. Darnton said a few drops of oil in turpentine can be used as a sealer. Also, a short oil varnish with pumice plus some other options like emulsions containing oil have been proposed, just to list some oil-wood contact options. If I recall it was the rosinate guy (Michelman or however it's spelled) who said to soak the plates with linseed oil, but I wouldn't do that again. I think it was Mr. Robson who noted: "Yes. Michelman thought the answer to preparing the white instrument was linseed oil [raw]. The ground on these violins is quite un-remarkable. Flat in reflection, greenish gray in color, no real depth. " I used Michelman's linseed oil on my very first violin because I'm gullible and believe what I'm told. It did dry, but took a long, long time and I agree with Mr. Robson about the appearance. But other sealers containing oil work better by some accounts. That's my story. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 This is what I wrote earlier, cleaned up. Hope it helps. The amounts and boiling points (bp) of the constituents of linseed oil are: Triply unsaturated α-linolenic acid (51.9–55.2%), bp 443C Saturated acids palmitic acid (about 7%) bp 351C and stearic acid (3.4–4.6%), bp 361C Monounsaturated oleic acid (18.5–22.6%), bp 360C Doubly unsaturated linoleic acid (14.2–17%), bp 229C Some makers use tiny amounts of it directly on the wood to good effect, either neat but mimimal ( oily rag method) or dissolved in excess solvent, turps. Most do not, putting a barrier coat ie ground or sealer before letting oil anywhere near the surface. If it soaks in before setting it will be there for a long time, undried. I think you'd want to use a tested oil ie one that us known to dry quickly. I tested this idea and the colour can be good. I wiped some liquid oil from under some which had nearly completely wrinkled on a scrap and let it dry in the sun. It developed a golden yellow colour. The constituents Iisted can vary wildly between sources of oils. If LSO was distilled to be mostly linoleic and linolenic oils it would dry as hard and as fast as tung oil but it has some very slow drying constituents which are possibly desirable to give a dried varnish film some flexibility. Oleic acid dries VERY slowly. Note it's around 1/4 of lso. Palmitic and Stearic acids == tallow and they never dry. They would sit in the wood forever and provide a good snack decades later. Luckily there's not much of them present. "Drying" is more complex than simple oxidation and somewhat chaotic but oxygen is deeply involved. Drying oils first put on weight as they oxidise, and swell slightly. Then they lose weight again and shrink back. Chaotic in that it also depends on the oil and the preparation of it. There are 100s of threads here on m'net to view about these topics. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 1 hour ago, FiddleMkr said: One of the most recent threads got to the topic of linseed oil as a ground. The general consensus (i think) was no. That is oil is a dampener and you don’t want that on a violin plate. However I have read that linseed oil can be used successfully as a ground, plus it gives the wood a base colour and highlights annual rings. It does “dry” after two weeks (or maybe longer?), and on my sample fiddle it is safe to say that after 22 years (anyway) it is dry enough to apply varnish on top. Does anyone know how long it takes for linseed oil to dry enough for oil varnish to be applied safely? Or since oil varnish has a linseed oil base, can oil varnish EVER be applied on top safely? OR can spirit varnish be applied to a linseed oil ground? I don’t want to muddy up the topic too much, but besides the one fiddle, I have shied away from oil grounds, because I was instructed to do so. However, the “primer” I was instructed to use is basically a clear oil varnish. So, the instructions were “don’t put oil on the bare wood, whatever you do, but instead put this primer on there, which is clear oil varnish.” The only thing I can figure is that the varnish must dry fast enough that it seals the wood, and oil varnish is different enough from just oil that it’s not a dampener? Is this correct? A fully cooked oil+resin varnish is quite viscous so it won't penetrate as readily. Adding solvent - the solvent soaks in faster and should block the varnish out a bit. That's also the reasoning behind the method of diluting oil before applying in fact I believe turps can be applied first, then oil plus turps. A 'ground' varnish is often suggested to be high in resins and low in oil, that would gel more quickly when applied Michelman suggested great globs of oil which is probably what lead to a lot of the alligatoring. I've seen one, it's not pretty. Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 I don't have the B&G book but I seem to remember someone saying they thought it was the same as the varnish but with no color added? I could be remembering wrong. Echard identified it as only linseed oil. In the upper wood cells. B&G also identified protein and an unidentified stain. Neither of them found a mineral ground. I suspect the Barlow / Woodhouse mineral layer was actually the varnish. On my last build I put a lean uncolored oil rosin varnish directly on the wood. I think it looks good. I can't say if it sounds good or not since I can't play it other than scratching out a little bit of an Irish tune, but that makes the dogs howl so I usually abstain from trying lol Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 In other news... I'm currently trying to dissolve 3 year old linoxin in alcohol. If it dissolves I'll put some on a rib scrap and see what kind of characteristics it has. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 Sort of related in that soap is made from oils: Some years ago there was a question raised on m'net about what it was that some wood dealers did to make their billets look so orange, to resemble aged wood even though it wasn't. I haven't been able to find that post but the answer was that they washed the outside with soap and left it in the sun to colour up a bit. I feel that is a useful piece of information. Quote Link to comment Share on other sites More sharing options...
Andreas Preuss Posted August 10 Report Share Posted August 10 I think all depends on the amount you are using. For the time to dry or let’s say solidify the painters rule is 3 days. Otherwise the method of the Mittenwald school would be a guideline: instruments receive a linseed oil coating when finished in the white. Then they are hung up to dry 2 years, mostly outside in the sun. While drying the surface becomes dark yellow. Before varnishing dust and dirt which accumulated is washed off with water and soap. The surface has then no ‘oily’ touch any more. It feels like dry wood and there is probably not much oil left. Under the varnish it has a nice reflection (but probably not enough depth for people trying to get the effects of a Cremonese ground) Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 6 hours ago, MikeC said: In other news... I'm currently trying to dissolve 3 year old linoxin in alcohol. If it dissolves I'll put some on a rib scrap and see what kind of characteristics it has. Did you use the intermediate steps of saponifying then acidifying? Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 4 hours ago, LCF said: Did you use the intermediate steps of saponifying then acidifying? not for this batch, but I have done that with small amounts and it works well. I let some LO oxidize and get dry then put it in homemade potash lye to dissolve then precipitated with acid. I think it was muriatic acid. For this I let it oxidize in a wide pan and when it was dry enough, ground it up fine in a meat grinder and then just let it age. It started in 2021 so three years of age. I put some in alcohol last night and this morning it is completely dissolved except for a few fine paticles at the bottom of the jar. as for putting LO directly on wood, I wouldn't have a problem with doing that. It can be applied in a way that it won't soak through. As mentioned by others, apply sparingly, ultra thin layer. I have done that on thin rib stock without it soaking through to the other side. The problem with putting LO directly on wood in that way though is that it seems to have a dull diffused appearance, not reflective. Here are some pictures From 2021, after putting it through the meat grinder. After about a year or more of aging it looks like this. I started another batch in 2023 and it looks like this now but it's still too sticky to put through the meat grinder. It looks like this now, reduced considerably in volume from when it went through the meat grinder. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 Thanks MikeC, that's great to see. As far as oil on wood and varnish ground coats are concerned,when I mentioned viscosity earlier it set my mind wandering. Viscosity is a complex topic but if we only think of the type induced by molecules getting larger by crosslinking or incorporating resins, it seems obvious that these won't soak into porous surfaces so readily and be more inclined to gel out on the surface before drying. The air exposed oil that I tested as a ground was very thick and gloopy, well on it's way to being linoxyn but not yet able to be dissolved in EtOH. Was it you who posted various pics of oils and varnishes dropped onto paper? That is a great idea. It reminds me of the electrophoresis gels my wife runs in her lab. You just need a few thousand volts there at the workbench. Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 a few thousand volts? lol, I have a 100 foot extension cord run from my house. I don't think that would work. I have put samples on paper and posted pics in the past but I'm sure others have as well. I'd have to go searching. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted August 10 Report Share Posted August 10 https://www.amazon.com/10000V-Supply-Electronic-Transformer-Approval/dp/B0B698BCBQ Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted August 10 Report Share Posted August 10 https://darntonviolins.com/old-linseed-oil/ The experiment is still running. Nothing has changed; it's been the same since I started, 30 years ago. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 1 minute ago, MikeC said: a few thousand volts? lol, I have a 100 foot extension cord run from my house. I don't think that would work. I have put samples on paper and posted pics in the past but I'm sure others have as well. I'd have to go searching. No matter. I was just thinking it was a good idea. I have some of that plain rosin dissolved in turps lying around unloved but it deserves a drop test. Thousands of volts are easy to get. I was safety checking some led fittings this week with my insulation tester which puts out 1000v. I often manage to get my fingers caught up in the probes. Explains a lot ... Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 1 minute ago, Michael Darnton said: https://darntonviolins.com/old-linseed-oil/ The experiment is still running. Nothing has changed; it's been the same since I started, 30 years ago. I'm really kicking myself atm thinking of all the jars of LSO I've thrown away when the contents went like that Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted August 10 Report Share Posted August 10 For a decade or two on and off I've been using an oil ground by putting a couple of drops of linseed oil in an ounce of turpentine, brushing that on and then immediately wiping it off. Let it dry for a couple of weeks, then repeat. The result is a total seal and the amount of oil on the whole violin sums to about five drops. Obviously there is no tonal effect whatsoever from doing this. I haven't decided how it looks in 300 years. I believe this procedure is consistent with Echard's observations. I have no reason to think that this is all there is to Cremonese ground, however, because I don't think it's going to replicate that ground in terms of physical characteristics (resistance to wear, especially). When the Barlow-Woodhouse work came out I wasn't the only one to note the very thin layer close to the wood that they didn't see or mention that looked a lot like oil. Restorers I showed the pix to immediately identified the "mineral" layer as pigment filled varnish, based on what they see, of what thickness, when cutting through the layers for repair. The idea that their thick, rubble-filled layer, the thickest layer on the wood outside of the wood, is invisible, as B/W suggested is, of course, ridiculous. Restorers also suggested that the thin upper layer that they called the original varnish was in fact the thin layer of modern varnish or polish coating that many restorers try to leave when doing a deep clean to avoid cutting through to the original varnish and damaging it. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 9 minutes ago, Michael Darnton said: (...) When the Barlow-Woodhouse work came out I wasn't the only one to note the very thin layer close to the wood that they didn't see or mention that looked a lot like oil. Restorers I showed the pix to immediately identified the "mineral" layer as pigment filled varnish, based on what they see, of what thickness, when cutting through the layers for repair. The idea that this thick, rubble-filled layer, the thickest layer on the wood outside of the wood, is invisible, as B/W suggested is, of course, ridiculous. There's a free download of that paper at ResearchGate https://www.researchgate.net/publication/237124417_Of_old_wood_and_varnish_Peering_into_the_can_of_worms Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted August 10 Report Share Posted August 10 Additionally, I have seen quite a few American violins from the mid 1900s when some makers were soaking the wood with oil to the point where I've seen oil stalactites inside, and that kind of oil treatment is definitely counterproductive to tone, but not exactly in the ways you might project in your imatination. Like anything else there's probably a sliding scale involved from 0 to 100. Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 1 hour ago, Michael Darnton said: https://darntonviolins.com/old-linseed-oil/ The experiment is still running. Nothing has changed; it's been the same since I started, 30 years ago. Unchanged? After 30 years I would expect it would have leveled out and turned black. Quote Link to comment Share on other sites More sharing options...
MikeC Posted August 10 Report Share Posted August 10 Actually... speaking of high voltage, I was thinking of building a jacobs ladder just for fun. Maybe try to replicate mad man Markum's time travel machine That's the science nerd in me. Quote Link to comment Share on other sites More sharing options...
LCF Posted August 10 Report Share Posted August 10 4 minutes ago, MikeC said: Actually... speaking of high voltage, I was thinking of building a jacobs ladder just for fun. Maybe try to replicate mad man Markum's time travel machine That's the science nerd in me. May be a bit risky to hook oil plus solvents plus blotting paper up to a Van de Graaff generator. Good ozone potential though. Quote Link to comment Share on other sites More sharing options...
Michael Darnton Posted August 10 Report Share Posted August 10 Danger, Will Robinson: That's not ozone you smell, it's nitric oxide, a precursor to nitric acid (when it joins with water in violin wood, for instance). Quote Link to comment Share on other sites More sharing options...
Don Noon Posted August 10 Report Share Posted August 10 Just an observation that probably won't add much information... The problem(s) with discussions about grounds and varnishes seem to go on forever, with no real conclusions at the end of it all... for good reason. "Oil ground" is not enough to describe all of the variations that you can have, which give different working properties and sonic results. A coating of straight linseed oil isn't the same as a few drops of oil in a lot of solvent. It's even worse with "oil varnish". What resins, and what ratio? How much of what kind of volatile solvent? Driers? Added minerals... pumice, fumed silica, something else? All of these details greatly affect what the varnish is like to work with, how it dries due to evaporation, and how it "dries" due to polymerization. It seems to me that each maker tries a bunch of stuff at the beginning, then develops a system that they like to work with, that looks and sounds good to them. For me, I prefer a thin resin/solvent as an initial coat on the wood, and then a ~1:1 oil varnish with some solvent so it's easy to apply, and still can be worked a bit with the fingers after the solvents evaporate. I know several makers who do something similar... but all slightly different. Quote Link to comment Share on other sites More sharing options...
David Burgess Posted August 10 Report Share Posted August 10 3 hours ago, LCF said: There's a free download of that paper at ResearchGate https://www.researchgate.net/publication/237124417_Of_old_wood_and_varnish_Peering_into_the_can_of_worms In my opinion, that's an excellent paper. 3 hours ago, Michael Darnton said: https://darntonviolins.com/old-linseed-oil/ The experiment is still running. Nothing has changed; it's been the same since I started, 30 years ago. My experimental outcomes have differed from yours. Quote Link to comment Share on other sites More sharing options...
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