Fulton Violin Plate Bending

[Bob Branstetter]

Going slightly off topic, there is a process that uses green wood to make violins. William Fulton, best known in violin circles for inventing the process for making Terpene violin varnish, came up with a controversial method for making violins using a process that is called plate bending. I tried to find a link to articles on plate bending, but I haven't been able to find one yet. Mr. Fulton takes green spruce and maple and cuts the wood into flat board that are slightly thicker than the finished graduation (max) with the length and width a little bigger than 1/2 the size of the violin plates. He puts these boards into a sealed high humidity chamber. The chamber is just a long box with a mixture of water and a little household ammonia (to prevent mold from forming) in a container below the wood. He leaves the wood in the box for several months. When he is ready to bend the plates, he devised a special clamping plate that the wood halves fit in. He places the wood and clamping plate into a large container of water that is heated to just below boiling (190 degrees) so that the lignum in the wood is softened. He periodically removes the wood and tightens the clamps down a little so that eventually the wood is formed into a shape like 1/2 of a violin top or back. It takes several hours to complete the bending process. The heat from the near boiling water dries out the green wood so that is nearly "dry" when it is removed from the water. Leaving the clamped wood out to dry for a few more days completes the process. He joins the bent plate halves and glues them together. He then uses conventional tools to finish graduation on the inside, cut the "FF' holes, and install purfling. He bends the bass bar the top using the same method rather than carving it to fit. Despite the very unconventional approach, the finished violins look to the eye just like a carved violin. AND... they sound good. My friend Anton Krutz of KC Strings had one of Fulton's violin brought into his shop by a customer. Anton told me the violin sounded fantastic. Anton even played around with making bent plates himself, but said he could not get the shapes he wanted by bending and has continued making his instruments the conventional way. Plate bending should not be confused with (steam) wood pressing like has been used on cheap violins in the past. The wood is not forced to assume some mould shape, but more like a controlled warpage so that the wood fibres are not cut or broken - just bent. I don't know of any bass makers who have attempted to make an instrument with the bent plate method, but it may be something to consider as good bass tonewood becomes increasingly expensive. I would imagine that you could resaw one normal set of bass tonewood wedge into enough bendable boards to make several basses. It would require some custom made equipment and quite a bit of space, but the possibilities are certainly there if that could be work out. Sorry if I left out any important details, but I think you can get the general idea about how it works.

[toman]

Very interesting about the "bent" violins; I'd definately like to read more. Kind of makes sense to me that they could sound great, since you'd esentially have the grain running all the way along the length of the instrument instead of having endgrain where it's been carved out. Seems like it would be along the lines of how increasing the string length improves tone. (Well, subjective maybe, but it seems to work on electrics, especially with low B strings...) Or maybe I'm crazy...

[Matthew Tucker]

Originally Posted by Bob Branstetter

eventually the wood is formed into a shape like 1/2 of a violin top or back.

So the plate ends up bent in two directions, or just one?

It'd be a helluva job flattening the edges to fit on the ribs again.

[Bob Branstetter]

Originally Posted by Matthew Tucker

So the plate ends up bent in two directions, or just one?

It'd be a helluva job flattening the edges to fit on the ribs again.

Again, I really wish there were a link that I could post for this. Unfortunately, I have not been able to find one. The way Mr. Fulton's clamping plate works, the edge that attaches to the ribs stays absolutely flat, so that is not a problem. I forgot to mention that part of the bending process involves using wedges, so yes the plate is bent in two directions. It ends up looking not much different than what your finished bass top would look like it you were to cut it in half, right down the center seam.

I found Fulton's article in one of the past issues of the Violin Society of America Journals. It is about 15 pages long, but I'll see if I can make a pdf of it for those interested. All I ask is that you promise not to post it or distribute it anywhere on the internet since it is copyrighted material from a private organization.

[Silversorcerer]

Originally Posted by Jazzdogg

Are you willing to share a few bibliographic sources? I'm in the middle of a thesis on "Urban Forestry" that includes sections on air drying, and kiln drying, and I'm always interested in reading new information related to wood technology.

This is knowledge that I picked up in both my studies of organic chemistry while in college and later in my practical experience with document, art, and photgraph conservation. Unfortunately, I do not have any bibliographical references handy and if I did they would be old and very many, but I can assure you that the chemical reactions between cellulose fibers and wood acid content (concentrated in the lignen) are well known in many fields. You might try googling lignen and acid content, cellulose hydrogen bonds, etc.
[edit note: see this link which I found after this post: http://www.conservationresources.com...erioration.htm
and this one:http://www.nrinstruments.demon.co.uk/wood.html]

Wood contact is avoided when framing or preserving important documents and art which are usually prepared on rag paper (pure cotton, linen, or other cellulose, no wood pulp content). This is because in time the rag is "burned" by the acid in the wood. This burning darkens the otherwise white paper and also makes it harder and brittle. It will do the same thing to cotton sheets that are stored in unlined pine furniture drawers for long periods of time. The acid in the wood does the same thing to the cellulose in the wood itself. The long term reactions in the wood proceed according to long established physical "laws" that depend on the ratios of the concentrations of the reactants, in this case the acid concentrations in the wood. Over time the rate of the reaction slows down due to excess acid being used up, but it doesn't stop until it reaches equilibrium. So you can predict pretty well that creating a more acidic environment in the wood (alcohol soaking) is definitely going to change that reaction rate. Which direction it goes will depend on whether the alcohol is more or less acidic than the lignen, if the lignen is alcohol soluble and many other things;- like type and species of wood (pine, spruce, and most conifers are more acidic than other woods generally). You might end up burning away considerably more of the hydrogen bonds in the cellulose than would happen by simply allowing the wood to age to equilibrium or you could wash out or dilute the lignen and prevent the aging from ever occurring. I'll admit that I don't know which it will be, but a "neutral" effect is less plausible.

The moisture in the wood also contributes to the process because acid base reactions proceed in a water solution. Even though water is neutral pH, it is the solution that allows the reactants to get together. Kiln drying interferes by removing all the water at once. Heat also accelerates most chemical reactions.

Another consideration about "dry wood" versus "aged wood", is that wood can pick up moisure as well as lose it over time. Like when your solid wood 100 year old door swells and gets stuck in the summer humidity. So even if you dry the wood out, it can get wet again. I got some 50 year air dried redwood from northern California that was pretty wet compared to what it is now after 3 years in Atlanta, but the acid reaction has still been going on for 50+ years, regardless of moisture content. The chemical aging process doesn't go back and forth, just slowly toward equilibrium, a little faster if the moisture content is higher.

Responding to other posts: Alcohol and water? Pure alcohol will take water right out of the air, your skin, or just about anything else that has water in it. So it is almost a "theoretical" stuff. In practice it exists ephemerally if at all. Alcohol and water are completely miscible.

Ammonia and wood bending? Ammonia solutions have been used for millenia to accelerate the bending of wood, so it is likely that the ammonia in Fulton's process does more than prevent mold. George Borun, a violin and double bass maker (also a chemical engineer) recommends dilute ammonia/water solutions for bending ribs. I do not have the reference handy, but I posted it before in a thread I started in this forum specifically asking if anyone else here was using ammonia in rib bending or had heard of it. In that thread I listed some links that also discussed that subject in furniture building applications and cabinetry. Apparently ammonia will darken certain woods and was used as a preliminary wood stain historically, and there is even some historical evidence of it's use in violin building for one, the other, or both purposes.

I'm all for someone doing experiments with alcohol dried wood, but keep in mind experiments are just that;- tried and true processes are also just that. Also you need controls to evaluate your experiments;- air dried wood from the same tree versus alcohol dried before you dare draw any conclusions.

[Silversorcerer]

Originally Posted by Matthew Tucker

So the plate ends up bent in two directions, or just one?

It'd be a helluva job flattening the edges to fit on the ribs again.

Have you ever seen the baroque guitars with curved and scalloped backs and ribs that are perfectly fitted to them? I don't think this applies to Fulton's violins, but there are ways to fit complex 3 dimensional shapes together at the edges and it is ancient luthier technology. Check out Dan Larson's reproductions.

More germain to double basses are the methods of the early gamba makers who bent the tops across from edge to edge and the ribs varied in width according to the curvature of the top. The Linarol gamba (very early) is like this. The tops were bent wood before they were carved. At one point the tops and backs were bent staves also, like barrels. Fully carved plates is pretty late methodology.

[Bob Branstetter]

Originally Posted by Silversorcerer

Responding to other posts: Ammonia and wood bending? Ammonia solutions have been used for millenia to accelerate the bending of wood, so it is likely that the ammonia in Fulton's process does more than prevent mold ...there is even some historical evidence of it's use in violin building for one, the other, or both purposes.
.

While it is possible that the small amount of household amonia could do more than prevent mold, you should note that unlike using ammonia and water for bending ribs, in the Fulton chamber, the water and ammonia never touch the wood. Because it is a sealed chamber, a small amount of ammonia gas will be released. Mr. Fulton says in the footnotes that "the use of the ammmonia gas is not absolutely necessary, but it makes the wood work and look better."

I have scanned the Futon article and made it into a PDF document. Anyone who wants it for their personal use, please send me an email that shows the email address where it should be sent. I can not send it through the TalkBass email facility. It is about 4 1/2 mb long.

(addendum)
While I was preparing the PDF, I did a quick re-read of the article and found that my memory of the clamping fixture was incorrect. The fixture actually looks like half of an outside violin mould. There is a top and a bottom. The two pieces of wood are clamped between the top and bottom. Four wood wedges are place in the open side of the fixture. These are what control the arching heights. As the wood lignum softens, the wedges are periodically driven in further between the two pieces of wood. There is a nice diagram in the article. Once you see it, you'll be able to picture in your mind how it works. Sorry if my previous description confused anyone.

[Silversorcerer]

Bob B., after re-reading your post on Fulton's methods I would think that while the wood is not immersed that leaving it for several months in an atmosphere with ammonia gas would be sufficient for the same chemical effects to occur. If the wood is in the same chamber with the ammonia, the gas will come in contact with and be absorbed by the wood, wood it not?

[Bob Branstetter]

Originally Posted by Silversorcerer

Bob B., after re-reading your post on Fulton's methods I would think that while the wood is not immersed that leaving it for several months in an atmosphere with ammonia gas would be sufficient for the same chemical effects to occur. If the wood is in the same chamber with the ammonia, the gas will come in contact with and be absorbed by the wood, wood it not?

And the point is? You think that without the ammonia, the wood will not bend?

[Silversorcerer]

My point is as originally stated: that it is likely that the ammonia in Fulton's process does more than prevent mold;- specifically that as Mr. Fulton, as quoted by Bob Branstetter, says in the footnotes that "the use of the ammmonia gas is not absolutely necessary, but it makes the wood work and look better."

I would take "work better" to mean bend more easily and "look better" to mean darken as if stained. It is difficult to read that as having anything to do with preventing mold, although I suppose moldy wood doesn't look good, but he might have been more direct if that were his meaning. And since he says the ammonia is not necessary (and since I could find no one who bends ribs on this forum using ammonia) I guess I would think the wood would bend without it, just not as easily. FYI, Borun's recommended solution was only 1% ammonia, so it doesn't take much.

[Damon Rondeau]

Mission / Arts & Crafts / Stickley style furniture (early 20th century) made of white oak was given a "fumed oak" finish. The wood object would be placed in a chamber with a pan of ammonia (not immersed in the solution, just exposed to its fumes; household ammonia isn't strong enough; I think it's ammonium sulphate at around 25% ammonia that's used but as I've said before, I'm no chemist; Fine Woodworking just featured this a coupla months ago.) The tannin in the wood reacts with the ammonia and results in the open-grain parts of the stock turning black with the closed-grain field of the stock turning a kind of honey-grey colour. You can try to get the same effect using stains but ammonia uniquely gives you that truly "fumed" look.

That's the only use of ammonia I've ever heard of in 30 years of woodworking. Are there other wood-crafts -- coopery, wagon-making, I dunno -- where there is any kind of ammonia-using tradition? Doesn't seem to widely exist in luthiery.

[Bob Branstetter]

Originally Posted by Silversorcerer

FYI, Borun's recommended solution was only 1% ammonia, so it doesn't take much.

There are days when I regret giving you the information about Dr. Borun's book. This is one of them.

[Silversorcerer]

Originally Posted by Bob Branstetter

There are days when I regret giving you the information about Dr. Borun's book. This is one of them.

That wasn't in his book in very much detail, it was on a website: http://www.scavm.com/blanky.htm
in a paper he wrote that went into far greater detail. Chances are that I would have found the same information without your guidance, but I still am indebted to you for the head start, and I still thank you for that. The book was kind of sparce on information on the ammonia process. It had some good plans for a full-sized bass and not a whole lot else.

I'm surprised that you regret sharing that and I'm truly sorry if I've offended you by pointing out the effects of ammonia that I've researched long since I read the information in the above link. Ammonia is also used in other cellulose processes, such as mercerization of cotton, although stronger bases are more effective for that purpose, Bending of wood for canoes is apparently the oldest known use related to cellulose.

As far as the chemical in solution or gas goes;- regardless of the concentration of the ammonia in the solution in the tray, it will fill the air according to the vapor pressures of various components in the air. In other words, it will be dependent on how much water vapor there is in the air more than it will on how much ammonia there is in the solution, as long as there is enough in the solution to reach the maximum vapor pressure for that substance in the given air volume at whatever temperature we are talking about.

And Damon's furniture example is not much different, it can be 1% in solution or 25% in solution, it will evaporate into the air and reach a given vapor pressure limit either way. Perhaps a stronger source is used because for furniture they are dealing with a larger volume of air and this is more efficient. So it is a little misleading that Fulton says a little ammonia gas will be given off. Over the course of months, exactly enough will be given off to reach the maximum vapor pressure at that temperature and atmospheric pressure within the sealed system.

A familiar illustration of the behavior of this type of reaction is inhalation of ammonia gas. Certainly if you inhaled ammonia solution it would burn your nose instantly. But I think anyone who has inhaled any ammonia gas, be it through agricultural use or just the fumes from the stuff that you get to clean glass knows that if you inhale the low concentration long enough, your nose will be just as burned. It's not so different for the wood. In general the rate of a chemical reaction will increase with the concentration of the reactants, and with increased heat as long as the heat doesn't destroy the reactants. It would proceed faster in solution than in air, but given moisture in the air and months, it will go to completion or equilibrium anyway. I would go as far as to say that I am certain that the ammonia does more than prevent mold in Fulton's process.

That the ammonia process doesn't widely exist in luthiery does seem odd to me. But maybe the staining effect, which is inevitable, may be undesirable in some cases. Who knows. Maybe luthiers have just been taught for ages to bend wood without using it, since it can be done that way. Maybe luthiers just don't like the smell. That would be me. I hate ammonia fumes. I find them very obnoxious so you won't find me bending wood that way if I can find another one.

[Bob Branstetter]

Originally Posted by Silversorcerer

book was kind of sparce on information on the ammonia process. It had some good plans for a full-sized bass and not a whole lot else.

Actually, I found the little book contained quite a bit of very useful information, but found the plans (on a couple of 11" x 17" pages) pretty useless. You should try actually making one some time instead of just talking about it argumentum ad nauseam.

[Silversorcerer]

How is whether I have built no instruments or a thousand going to change what happens with alcohol and wood or ammonia and wood? No one's experience or inexperience is going to affect the wood chemistry at all. My observations about Fulton's procedures, which I thank you for bringing to light, are accurate. I engaged in intelligent discussion of the chemical details of this process. Fulton is bending wood and using ammonia to facilitate it. Are you saying this observation is incorrect? If so please point out where and how.

At some point, simply saying, "you haven't built anything" rings hollow as well as familiar. It's always the last arrow in the quiver, growing duller with each use.

You don't hear me chastising luthiers to go take 4 years of science classes now do you? I simply share what I know when it's relevant.

[Bob Branstetter]

Originally Posted by Silversorcerer

My observations about Fulton's procedures, which I thank you for bringing to light, are accurate. I engaged in intelligent discussion of the chemical details of this process. Fulton is bending wood and using ammonia to facilitate it. Are you saying this observation is incorrect? If so please point out where and how.

The fact is that you have not read any of Fulton's articles and you refuse to accept the fact that wood can and frequently is bent without the aid of ammonia. Would it help if I told you that Fulton had also bent plates straight from tree with no ammonia? The article I quoted was his first on the subject and he published several followup articles in the VSA and CSA journals as he refined the process. Sorry, but the luthiery world can exist quite nicely without ammonia.

[1st Bass]

Bill still lives in Idylwild, CA, and sells a video of himself bending plates, and explaining how/why he does what he does. I think I paid $16 for my copy.

I used the method to bend a flat-back bass set of plates and make a roundback of them...my workmanship is still sub-standard, but the process does work, as I used it on 1/2" maple. I did not use ammonia, and as a result, got a little mildew during the process-- I sprayed a little bleach/water solution to kill the midew, but the bending was complete before the bleaching, and was not affected in any way.

Bill's a pretty interesting guy to talk to...you'd like him, Bob.

[Silversorcerer]

Originally Posted by Bob Branstetter

The fact is that you have not read any of Fulton's articles and you refuse to accept the fact that wood can and frequently is bent without the aid of ammonia.

I've never claimed that ammonia is necessary for wood bending. I really don't know where you are getting this. And you have no idea what I may or may not have read. So let's separate your suppositions from what you call facts.
What I said was there is an inevitable chemical reaction between wood and ammonia that aids bending when the two are put together;- as in Fulton's process. That's quite different from saying ammonia is a necessary component. Fulton himself says, it isn't "absolutely necessary". That would seem to me to indicate that while not "absolutely necessary" it may be pretty helpful. And why do I need to read Fulton to draw conclusions about chemistry? It's just chemistry. Fulton didn't invent or discover that. And even if that isn't the first purpose he is using it for, there is no way in the process that you describe that the ammonia isn't going to have the same effect as it does in Borun's process. That is the chemical relationship between ammonia and cellulose microfibrils. Put the two together and it will happen. That seems to be the only fact here that someone is refusing to accept and it is not me.

Personally I've never bent wood with ammonia and I couldn't find anyone else who builds instruments other than Borun who has reported using ammonia to facilitate bending. Now there is Fulton. So that makes the only two that I know of. There may be more. History is not so well documented and some methodology is undoubtedly obscure and perhaps completely lost. I did find some contemporary cabinet making instructions for the procedure for bending wood after soaking in ammonia. If there is anywhere in any of my posts on this forum that I have stated that ammonia is a necessary component for bending wood, I challenge you to produce it.

Great if luthiers can do without ammonia. Like I stated before, I find the fumes quite noxious and bothersome and hopefully I can get along without using it also. But if I find a way to use it without suffering the fumes and it significantly makes the job easier, I might use it. Good to know about in any case.

[Mudfuzz]

I did a few tests on scrap awhile back with ammonia [just household crap, can't remember the make or makeup], I didn't find it worked any better then water, and it smelled bad, really bad. After that I lost interest [sorry] on the subject to bother with it. Heat with a little water works great and smells nice, which makes the process rather fun to do as well.

[Bob Branstetter]

Originally Posted by 1st Bass

Bill's a pretty interesting guy to talk to...you'd like him, Bob.

I did get a chance to talk to Bill briefly at a joint CAS/MVA meeting in Dearborn, MI (1996). At that time I was really more interested in talking to him about the Propolis ground and Terpene varnish that was on his violins. He had one of his bent plate violins and was showing it off to everyone. Unfortunately, I never got to hear what it sounded like then, but when Anton Krutz says something sounds good, I know it must be good. I'm currently in the process of polymerizing a couple of gallons of gum turpentine and hope to have enough of Bill's Terpene varnish done by the time I get a bass finished that I'm making for my personal use. I do hope that I will get to meet Bill again sometime in the future and when that happens I'll have lots of things I would like to ask him. He is truly one of the great innovators of the modern age violin community.