Identifying bowlback mandolin and question about black inside

[brunello97]

John, I don't have any photos of that old Washburn, but just checking now in Keef's "Washburn" book, in my edition on page 112 there's a tightly cropped view of the cross bracing and he makes note of it as well on page 113 in his 3.3 "General Appointments".


Not sure if you have the book, but he writes for the 1887-1896 models: "....Ribs are usually cross-braced on the inside with an oval wood centerpiece on which the Washburn logo...."

He continues for the 1896-1905 models: "....The cross bracing method (1889) is abandoned in favor of the traditional paper gluing of the inside ribs..."

I can get a photo up of but the original isn't very big or very clear either...but it does show what was inside mine.


I'm an architect, not a structural engineer, but I have built some thin shell masonry roofs of different sizes. My guess is that a bowlback bowl does behave in some manners as a shell structure and in some ways as a series of connected bent arches spanning from tailblock to neckblock. These types of constructions don't always perform in a singular manner but often as hybrids.

The thin shell masonry vaults / shells I've built definitely benefited from a skim coating of mortar on the interior. Of course they were independent tiles, not spanning ribs so how relevant they are to this discussion is up for grabs.

I suppose if it were as John described, this paper lining was tautly applied and "shrink wrapped" pulling the staves laterally into compression with each other it might add some strength to the assembly. But I've often seen the linings applied like a bad wallpaper job, which puts that into question. It might have worked as intended on some and not on others.

Somewhere, not sure if it was in print or watching online, I recall seeing bowlback ribs being assembled and the narrator / captions clearly spoke of a paper liner place on the mold as a type of "slip sheet" such as Mike describes. Or as far as my Italian language skills go it did.

Whether or not that was the same paper that wound up lining the finished bowl was not clear to me.

One or the other? Seems likely both could have been in play. The idea of a liner serving as a reinforcement must have come to someone's mind at some point. Bowlback ribs were probably splitting apart not long after the were made, for a century or more before my Washburn.

John D'A's cross rib strips seem to be clearly intended to do so.

Don't know if I've contributed anything here, but, man I enjoy these wonky deep dives into bowlback construction.

My partner is a structural engineer who is all over thin shell and tensile structures. I'll bring a bowlback into work and leave it with him and get his take. I know he'll dig it.

Thanks for getting this discussion going!

Mick

[Richard500]

Thanks for that d’Angelico photo; it ‘reinforces’ my amateur idea that such a fabric could be intended as structure. Actually, it’s a fairly easy experiment to do. Way back when I helped build glass kayaks, which are bowlbacks of a sort, they were analogous to something woven embedded in a matrix of adhesive. Cloth in glue is very strong; thin edge-jointed wood not so much. Note the main seam in the top may (?) have original tape too.

[MikeEdgerton]

I think that bowls were a work of art that was beyond what the mortal woodworker could imagine. It took special skills to get the staves shaped, aligned and attached to each other. Chris Martin discuses this in this video. I'm sure that there were folks looking to streamline the process and that there were also people that learned and perfected the craft. In a truly factory driven world attempts were made to shortcut things, for example the Lyon & Healy faux split stave to make it look like there were more than one stave on the outside to reduce the total number of staves. More staves equals a better instrument maybe. The materials they had to work with in the circa 1900 era most likely changed greatly in the next three decades. There is also a reason why the carved top and back mandolins, as well as the flat backs took off. If in fact you want to see the final evolution of the attempt to make the manufacturing of bowlback instruments easier one only has to look at Ovation and that came 70 to 80 years later. If you're looking for a builder that is still doing the painstaking work of getting a bowlback mandolin out to the player then Brian Dean is the man. There are pictures of his work and he has pictures of his restoration work on his site. Martin's work and Mr. Deans work would have been and are in demand to that market and would have been and is priced accordingly. The vast majority of what was sold into that market were a bit more modest and as necessity is the mother of invention I'm sure somebody came up with better ways to brace while building bowls, I just don't think it was done with thin paper and cloth. I think it's still in the talents of the woodworker and the quality of the work.

[Bill McCall]

I think that bowls were a work of art that was beyond what the mortal woodworker could imagine. It took special skills to get the staves shaped, aligned and attached to each other…………………. I think it's still in the talents of the woodworker and the quality of the work.

I certainly agree that bowlbacks show a very high degree of skill on the luthiers part, but ‘mortal woodworkers’ have been building watertight barrels for centuries before bowlbacks appeared. And it’s a lot harder to bend thick wood and make a watertight edge along a long serface than join the short, thin mandolin ribs, not that either is a particularly easy skill.

I guess I’m just saying that fancy and musical doesn’t necessarily show more skill than sturdy and serviceable.

[MikeEdgerton]

Not to besmirch the cooper's trade, it is indeed a wonderful craft but comparing a cylindrical vessel with 1/2 inch thick or greater staves to a vessel that is made from staves that are 1/8 inch thick or less and not uniformly shaped is kind of like comparing apples to bananas. You could take a cooper and mandolin luthier from that age and I'm pretty sure the luthier could make the transition to other trade a little faster. I'll note that the vast majority of the barrels currently made are no longer made of wood for a reason as well. If I was going to choose a trade to compare I might have gone with a shipwright. They would at least be dealing with a none uniform stave shape.

[MikeEdgerton]

This is going to be a bit of thread drift but as I am now really curious about bowlback construction historically I'm looking at examples of bowled instruments that are still being built in the world and how they have changed and stayed the same. The Americans have no part in the invention of the bowlback, that was an import from the old country and even though we had a thriving industry here we certainly have made no real major attempt to continue the craft. It hasn't died in other areas of the world and the mandolin wasn't the only bowlbacked instrument. Here are three interesting videos that are in Greek with English sub titles about the overall construction of bouzoukis. I'm going to assume that we manufactured here in the US was based at least partly on some of the same methods still seen here.

[Bill McCall]

While it may be apples and bananas, Whiskey barrels are not cylindrical. There are 13,000,000 in Kentucky alone almost all less than 10 years old.

Staves are curved and tapered from the middle in each direction.

I would think working with smaller, lighter and more uniform pieces is perhaps no more challenging than manipulating larger ‘ribs’. Retraining would be needed in moving to either trade.

[MikeEdgerton]

While it may be apples and bananas, Whiskey barrels are not cylindrical. There are 13,000,000 in Kentucky alone almost all less than 10 years old.

Staves are curved and tapered from the middle in each direction.

I would think working with smaller, lighter and more uniform pieces is perhaps no more challenging than manipulating larger ‘ribs’. Retraining would be needed in moving to either trade.

You missed the point, the staves are by design all the same. Sorry, it's apples to bananas again. The mandolin staves aren't all that uniform, that's the difference.

Anyone that wants to see the modern cooperage in action.

https://www.youtube.com/watch?v=fF38BxIqxL0

[brunello97]

While I am enjoying these posts and learning as well, I think the "barrel vs bowlback" debate is a non starter, a red herring.

Not that I'm an 'expert woodworker' by any means.

But I have built a good number of stave drums back in the day, both straight sided and with a bowed profile aka conga drum, which unlike most barrels are assymmetrical across their horizontal axis.

And I've bulit a few sets of bata drums which were also staved and had an "hourglass" cross section.


These all had virtually identical staves and the heating / bending process was dependent on the outer rings or the banding clamp rigs I devised.

That I was making a complete circle with the staves was crucial to the operation. Making a one sided barrel?


I haven't built a bowlback mandolin from scratch, but I've repaired the bowls on more than a few.

I never once put the two together in my mind. They were / are so different from one another in so many fundamental ways.

I don't think my drum making skills (such as they were) have any influence whatsoever when it comes to wrangling a bowlback....particularly without a mold / formwork.


Watching a friend here build a small wooden sailboat had a lot more resonance with me viz bowlback construction than a barrel ever would.


I don't support the barrel making reference at all in a discussion about the craft of making a bowlback.

I think it's a dead end for a productive conversation, though the linked videos are fun to watch.

Mick

[MikeEdgerton]

What I had really hoped to see in the videos of the bowlback bouzouki build was what they used to keep the glue from the staves from sticking to the mold. I wondered if they waxed it or something and unfortunately the pieces I really wanted see were just not shown

It did appear they glued the bowl together and expected it to stay together and I was also surprised to see them fluting the staves on the mold although I don't really know what else I expected. I guess I thought that would be done pre glue. The use of "protein" based glue wasn't a surprise but I did expect it to be hide glue.

[brunello97]

Carlo Mazzacarra has some videos of him working on cutting le scannellature or grooves / flutes on a bowlback.

He's working it off the mold with the top on and going at it pretty hard with a series of round files.

There's a lot of material to take away to get that profile after the staves were bent and assembled.

Mick

[Richard500]

I think we’re all agreed that piecing together 40+ wood strips isn’t a trivial job, and that mandolins probably make lousy whiskey containers, and that barrels are barrel shaped for one simple reason, and in Mick’s world, a barrel vault also is something different.
However, for your consideration, if not edification, I offer gourd-based and hollowed solid variations, which may be common ancestors, and just to be poetic, ships made of planks with flat decks. My (yet to be figured out) Turkish saz somehow involves hollowing a very large chunk of (probably) mulberry wood into a thin shell without any drying cracks or the use of automation. How this is done is more unlikely than gluing strips on a mold.
So what, or rather why, the bowl back? First, it’s an acoustic chamber comprising a resonant chamber with a port, driven by a more or less flat membrane. Could be anything, IMHO, that is, its elastic properties are minor, and the shape is also not primary. Second, together with the soundboard, it has to support the large load from the strings, which fortunately is nearly aligned with the top, so the bowl is a structural element mostly in tension. And that’s about it. Is it meant to be the strongest possible shape for its weight or economy of material, or is it just evolved from those gourds or ships or bird eggs or vegetation? Speculation.
Never shy with opinion, I think it’s mostly responding to the material limits of wood that can be heat molded, largely in one plane, therefore narrow and thin, and is edge-glued (except for the part that wraps around the back) rather than lapstrake mostly for appearance.

But yes, to anyone who has brushed up against woodworking, these things are impressive, and whether made by vastly-skilled artisans, one shaped stave at a time, or cranked out on those production lines of yore by virtue of machine accuracy, are just really neat.

[MikeEdgerton]

...Carlo Mazzacarra has some videos of him working on cutting le scannellature or grooves / flutes on a bowlback.

He's working it off the mold with the top on and going at it pretty hard with a series of round files.

There's a lot of material to take away to get that profile after the staves were bent and assembled.

Mick

In my world of thought I would have assumed they would be using some sort of jig to determine where and how deep to go but it appears to be a job that is eyeballed. That's more amazing to me.

[Richard500]

In my world of thought I would have assumed they would be using some sort of jig to determine where and how deep to go but it appears to be a job that is eyeballed. That's more amazing to me.

Or even having most of the material removed when the staves were flat!

[MikeEdgerton]

Or even having most of the material removed when the staves were flat!

Taking that into consideration as well, it must take a deft hand.