Beginning violin making

[Davide Sora]

3 hours ago, Andreas Preuss said:

At least the one I restored in Morels shop the Godowski (was it 1727?) for sure. 

There is also somewhere a comment by John Dilworth in an article. I just don’t agree with his interpretation saying the corner areas were thinned down from the outside after finishing the rib garland. (Don’t ask me in which Strad magazine on which page) 

Anyway, my complete analysis of Antonio Stradivaris designs brought me step by step to the conclusion that all was about ‘precise, fast and efficient’ work. And bending ribs over a mould is really fun and spares you burning your fingers by accident.

I'm not familiar with the Godowski, but I remember Dilworth's article, which I tended to agree with, as the same phenomenon has happened to me several times with my violins. I've bent the ribs without using the hot iron for a while, but honestly, I think it's more complicated and slower. Nothing is faster than using a very hot iron, which forces you to be quite quick and efficient in bending. But it could very well be as you say, everyone sees the evidence that fits with their own experience, including me; no certainty is possible.

Anyway, this is the Tuscan 1690:

[Andreas Preuss]

On 6/20/2026 at 11:39 PM, Davide Sora said:

I'm not familiar with the Godowski, but I remember Dilworth's article, which I tended to agree with, as the same phenomenon has happened to me several times with my violins. I've bent the ribs without using the hot iron for a while, but honestly, I think it's more complicated and slower. Nothing is faster than using a very hot iron, which forces you to be quite quick and efficient in bending. But it could very well be as you say, everyone sees the evidence that fits with their own experience, including me; no certainty is possible.

Anyway, this is the Tuscan 1690:

Davide, certainly every one cherishes in one way or another his/her own method. 
 

Interesting pictures of the Tuscan where the ribs are definitely not thinned town at the corners. What catches my eyes here are those bumpy lines at the corners. If the pictures are from the front: the upper left (bass) side and the lower left look pretty “bad”. The C ribs could be a fraction thinner than the others? (At least the left side c rib looks a fraction thinner to me in total.)

——

I don’t know. your quick method works with modern equipment, a precisely formed iron with a smooth surface, electric heat control and eventually paper sandwiched in between rib material and the hot iron. 
 

A bending iron was certainly not so handy in the 17th century if the assumed form by Sacconi is correct. Putting it in fire wait until it heated up to the right temperature (without a control light) then clamp it somewhere somehow presumably holding it with leather gloves. And last not least are there anywhere old bending irons left? All sorts of wooden things survived, just this big chunk of metal didn’t go into the collection of remaining materials of the Stradivari workshop. (?)

A little better seems to be another assumed type where hot coal was filled into the iron to heat it up. If this was made by casting the iron (like iron pots of the period) there is the problem how to make a smooth surface on the outside. 
 
 

[mendel]

21 minutes ago, Andreas Preuss said:

Davide, certainly every one cherishes in one way or another his/her own method. 
 

Interesting pictures of the Tuscan where the ribs are definitely not thinned town at the corners. What catches my eyes here are those bumpy lines at the corners. If the pictures are from the front: the upper left (bass) side and the lower left look pretty “bad”. The C ribs could be a fraction thinner than the others? (At least the left side c rib looks a fraction thinner to me in total.)

——

I don’t know. your quick method works with modern equipment, a precisely formed iron with a smooth surface, electric heat control and eventually paper sandwiched in between rib material and the hot iron. 
 

A bending iron was certainly not so handy in the 17th century if the assumed form by Sacconi is correct. Putting it in fire wait until it heated up to the right temperature (without a control light) then clamp it somewhere somehow presumably holding it with leather gloves. And last not least are there anywhere old bending irons left? All sorts of wooden things survived, just this big chunk of metal didn’t go into the collection of remaining materials of the Stradivari workshop. (?)

A little better seems to be another assumed type where hot coal was filled into the iron to heat it up. If this was made by casting the iron (like iron pots of the period) there is the problem how to make a smooth surface on the outside. 
 
 

That's pretty interesting. I never thought about how they did it then! 

 

[Andreas Preuss]

3 hours ago, mendel said:

That's pretty interesting. I never thought about how they did it then! 

 

The thing is, nobody knows it precisely, neither do I. It’s just that you start making your thoughts when you look on historic technologies. To know for better I tried at least to reconstruct tools and test them out in practice for not only theorising about it. (The most daring tool I made was a fly wheel driven jig saw for cutting f holes which worked well far beyond my expectations, but this doesn’t really belong to the topic of your thread…)

When copying archings, I would never go 100 percent after the actual arching taken from the instrument in question. There are two types of distortion involved. One is that the Center of the top sinks in, sometimes as far that you can see a very slight concave curve in the center of th long arch. The other distortion is by far less noticeable because the whole body is getting twisted over time so that if you would take off the back the rib garland wouldn’t lie entirely flat on a flat surface. 
 

My advice is to think about the idea behind an arching and ‘translate’ it to your own making. 

[Davide Sora]

7 hours ago, Andreas Preuss said:

Davide, certainly every one cherishes in one way or another his/her own method. 
 

Interesting pictures of the Tuscan where the ribs are definitely not thinned town at the corners. What catches my eyes here are those bumpy lines at the corners. If the pictures are from the front: the upper left (bass) side and the lower left look pretty “bad”. The C ribs could be a fraction thinner than the others? (At least the left side c rib looks a fraction thinner to me in total.)

——

I don’t know. your quick method works with modern equipment, a precisely formed iron with a smooth surface, electric heat control and eventually paper sandwiched in between rib material and the hot iron. 
 

A bending iron was certainly not so handy in the 17th century if the assumed form by Sacconi is correct. Putting it in fire wait until it heated up to the right temperature (without a control light) then clamp it somewhere somehow presumably holding it with leather gloves. And last not least are there anywhere old bending irons left? All sorts of wooden things survived, just this big chunk of metal didn’t go into the collection of remaining materials of the Stradivari workshop. (?)

A little better seems to be another assumed type where hot coal was filled into the iron to heat it up. If this was made by casting the iron (like iron pots of the period) there is the problem how to make a smooth surface on the outside. 
 
 

Yes, it also seems to me that the Tuscan Cs are slightly thinner. There are some bumps and even some visible partial flame cracking, all of which can happen with any bending method. Stradivari wisely placed these cracks on the gluing surfaces, where they don't present any problems.

As for modern equipment, I don't think it was a problem to have a smooth, well-shaped bending iron in the 18th century; all it took was a file and a bit of skill, and Stradivari certainly had plenty of them. I, too, in school and during the early years of my work, used bending irons heated on the stove, and I even had to file them flat with a file and elbow grease (the electric ones weren't widespread yet, at least here in Cremona). They worked well, and if you have two, you always have a hot one when the first one cools down. Additionally, there are sometimes burn marks on the Cs on antique violins that may indicate the use of heat at some stage of bending. These bending irons are not present in the Stradivarian finds here at the museum, but I suspect that the work tools were passed on to some other luthiers who used them; I don't think they were considered valuable enough to be sold to collectors.

However, I'm not entirely sure what method they used to bend the ribs, as a hot iron is certainly not the only option, and there's always the problem that heating them in summer might have been annoying, to say the least, and not as straightforward as in winter, when the stove was probably always on to heat the workspace.

For a while, I used a cold system to bend C ribs (like the two-roller system used for guitars), soaking the ribs for about ten minutes in plain water, but I was always afraid of using plasticizers like ammonia or the vinegar you mention, as they're quite damaging to the wood's components. Could you elaborate on the method you mentioned with the water and vinegar bath? Like how much vinegar to add to the water, and how long to leave them to soak? 24 hours seems like a long time to maintain the health of the wood, given the presence of an acid that is harmful to lignin and cellulose.

Then there's the possibility that they used steam, or boiling the wood, but even these methods could be a bit harsh on the wood's health.

Who knows, I fear it will remain an open question.

[Andreas Preuss]

36 minutes ago, Davide Sora said:

Could you elaborate on the method you mentioned with the water and vinegar bath? Like how much vinegar to add to the water, and how long to leave them to soak? 24 hours seems like a long time to maintain the health of the wood, given the presence of an acid that is harmful to lignin and cellulose.

I am not sure if the wood structure is damaged with plasticisers. My understanding is that it loosens temporarily the cell structure, just as water and heat. It would take a prolonged time to degrade cellulose and even more time to degrade lignin.
 

But at least, when the vinegar-bent ribs have dried they just feel as rigid as those bent without. 

I was testing all sorts of concentrations up to pure vinegar. I forgot how much was the minimum needed, I think it was one part vinegar on 3 parts of water, so 25% to have a noticeable beneficial effect. 
 

Anyway, in combination with heat it bends even quicker, but if the wood touches the iron it turns black because the remaining vinegar acid reacts with iron forming black iron acetate. 
 
Maybe one day examination of cell structures on those instruments reveals the use of vinegar or its absence. 

——-

One could also muse about the fact that inside moulds had been used for holding pre bent ribs which were still a little moist. 

———

on the other hand, makers using no mould were certainly forced to use a bending iron to form their shape to a definite curve. 
 

Out of curiousity (and maybe to convince me of the opposite) do you have any picture of those oven heated bending irons?
 

 

[Dr. Mark]

23 minutes ago, Andreas Preuss said:

Out of curiosity (and maybe to convince me of the opposite) do you have any picture of those oven heated bending irons?

Adding fuel to the fire so to speak - a metal rod with one end held in a fire will have a thermal gradient along its length.  A working range of heat somewhere along the rod can be maintained just about forever with a little adjustment of the fire or the rod's position.  A good temperature can be found by where a drop of water on the surface turns to steam on contact but without popping off.

[Davide Sora]

1 hour ago, Andreas Preuss said:

Out of curiousity (and maybe to convince me of the opposite) do you have any picture of those oven heated bending irons?

I don't have any pictures of mine; I gave them away after switching to electric. But it so happens that the shop where I bought them (L.A.C. in Cremona, now All4Violins) still has a few. They're probably old stock; I don't think they still make them. I'm copying and pasting the image from their website. Mine was the same except for the clamped handle, which was square instead of hexagonal.

 

But the shape could also be different, perhaps like the one seen in this video, or even a simple, more or less oval bar. Not at all difficult to make.

 

[mendel]

On 6/22/2026 at 10:10 AM, Davide Sora said:

I don't have any pictures of mine; I gave them away after switching to electric. But it so happens that the shop where I bought them (L.A.C. in Cremona, now All4Violins) still has a few. They're probably old stock; I don't think they still make them. I'm copying and pasting the image from their website. Mine was the same except for the clamped handle, which was square instead of hexagonal.

 

But the shape could also be different, perhaps like the one seen in this video, or even a simple, more or less oval bar. Not at all difficult to make.

 

Hey, nothing to do with the conversation. 

I recently saw a video of you fitting the bass bar, first of all you work is beautiful and perfect. 

I saw that you put some air on the chalk (or maybe it was something else) what is the reasoning of that? 

And do you have any tips for putting on the bass bar? 

[David Beard]

I don't have a well researched opinion on how the makers bent ribs.   

My suspicion is that the easiest and most direct approach would have been a combination of heat bending to establish the basic shape and main curves, then clamping the wetted rib into the wooden form for a cycle or two of wet to dry resetting of the wood fibers.