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Urban Luthier

Cello Graduations for Poplar Backs & Beech Ribs

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I'll be working on a cello in the next year (likely inspired by the smaller Rugeri, Rogeri forms). I have nice off quarter 2-piece of poplar for the back. I'll likely use quartered beech for the ribs.

I'm a little out of my depth here, so I'd like some advice from members who have had experience using poplar in cellos 

  • Back Graduations - my poplar is about 40% lighter than maple. As a starting point, should I simply scale up maple grads by 40% across the board (centre, lungs and edges) and monitor stiffness along the way?  Impacts on arching? higher and fuller at the edges to accommodate for the extra thickness?
  • Ribs - quartered beech -- how thick should they be? 1.5 mm? thicker?

Any guidance would be much appreciated!

Chris

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25 minutes ago, duane88 said:

Start out with 14mm or so for the back. The ribs shouldn't need to be any thicker than normal.

Poplar is extremely variable and depending on what you have your grads may be anywhere from just slightly thicker than maple all the way to12 or more in the center. The areas in the lungs should be some what thicker than maple but due to the fact that the edge thicknesses remain pretty standard the poplar instruments will be proportionately thicker in the center in relation to the lungs and edges when compared to maple. 

Beech is great stuff and ribs should be standard 1.6 or so. I personally would not use beech for a neck. If you want to make a beech head then graft it onto a maple neck to avoid bending.

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Thanks Nathan and Duane.

My poplar is likely local to Ontario or northern US. It is 2-piece cut off quarter and appears to be a bout 40% lighter than a maple of the same dimension. 

Beech is strong but it isn't as hard as event the softer maples, so I agree with Nathan's advice. Plus it looks stunning when it is cut on the quarter. The scroll will likely be either beech or pear grafted on to a maple neck. Cello wood is very expensive so I'm trying to work with what I have.

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Are you talking about European beech or american?

From what I know american beech is similar to hard maple in most parameters and european is even harder and heavier. I've commonly worked with EU beech as it is one of the most common local hardwoods.

Once it is seasoned the wood is pretty stable. I don't see a reason why it could not be used for neck. I've seen some quilted and curly beech trees that I wouldn't hesitate to use for backs, sides and necks and would rival any maple in beauty.

Look up wooddatabase for more detailed information.

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I was always told that poplar and willow were best slab cut for backs, because of their tendency to split if used quarter sawn. How true it is I don't know, but I've never used quartered poplar. I'd like other views on this.

I use hard Italian poplar and leave it about 10 or 11mm in the centre, as I've seen in good old cellos. For the softer red willow I've gone as thick as 12 or 14.

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Here is the back -- the photos don't do it justice -- the wood is has an iridescent-like reflectivity. 

Conor there is a small split mark along the winter growth at one corner, so you may be right about the stability of slab vs quartered poplar. This billet is cut just off quarter.

poplar_back.jpg

poplar crack.jpg

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5 hours ago, Conor Russell said:

I was always told that poplar and willow were best slab cut for backs, because of their tendency to split if used quarter sawn. How true it is I don't know, but I've never used quartered poplar. I'd like other views on this.

I use hard Italian poplar and leave it about 10 or 11mm in the centre, as I've seen in good old cellos. For the softer red willow I've gone as thick as 12 or 14.

You’re scaring me Conor, as I bought a one piece quarter sawn willow back for a cello I will be building for myself. 

-Jim 

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5 hours ago, Jim Bress said:

You’re scaring me Conor, as I bought a one piece quarter sawn willow back for a cello I will be building for myself. 

-Jim 

Sorry Jim.

I really don't know how true it is. I'd love Nathan's opinion, he's made more cellos than I've had hot dinners.

8 hours ago, Urban Luthier said:

Here is the back -- the photos don't do it justice -- the wood is has an iridescent-like reflectivity. 

Conor there is a small split mark along the winter growth at one corner, so you may be right about the stability of slab vs quartered poplar. This billet is cut just off quarter.

poplar_back.jpg

poplar crack.jpg

It does look very nice.

To be brutally honest if I may, I don't like this cut for instruments. For me, the rows of figure aren't in sympathy with the form. 

The flame in your piece doesn't seem too deep, but in deeply figured pieces, the grain really dives straight through in the dark figure. It's effectively headwood, hard to carve like a knot, and very prone to shrinking and at least local cracking. I wonder about it's acoustic properties too.

I took delivery of five cellos myself recently. One is fairly quartered, and it's stunning.  Despite the temptation, I think it'll become a piece of furniture or something.

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There was a discussion some years ago where some pretty knowledgeable people thought that quartered poplar ribs would crack as opposed to slabbed ones. I have made many poplar instruments and have always used  quartered or off quarter ribs with no cracking yet. For the most part I use slabbed backs but  think I have made a few two piece quartered backs and am not aware of any problems.. No cracks any where yet and no reason for me to think that the basic rules of wood structure are any different between poplar and other hardwoods.These days I much prefer willow to poplar and again there are a bunch of different woods out there flying under the banner of willow and poplar which may be very different from one another. I have not used European or Lombardy poplar at all so know very little about it.

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4 hours ago, Conor Russell said:

To be brutally honest if I may, I don't like this cut for instruments. For me, the rows of figure aren't in sympathy with the form. 

The flame in your piece doesn't seem too deep, but in deeply figured pieces, the grain really dives straight through in the dark figure. It's effectively headwood, hard to carve like a knot, and very prone to shrinking and at least local cracking. I wonder about it's acoustic properties too.

Thanks for your honesty Conor, it is a lot of work at my stage of development to invest in something that doesn't have the right acoustic or aesthetic properties. I spun through the Rugeri cellos I could find and none seem to have quartered poplar backs - perhaps there is a reason for that.

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1 hour ago, nathan slobodkin said:

There was a discussion some years ago where some pretty knowledgeable people thought that quartered poplar ribs would crack as opposed to slabbed ones. I have made many poplar instruments and have always used  quartered or off quarter ribs with no cracking yet. For the most part I use slabbed backs but  think I have made a few two piece quartered backs and am not aware of any problems.. No cracks any where yet and no reason for me to think that the basic rules of wood structure are any different between poplar and other hardwoods.These days I much prefer willow to poplar and again there are a bunch of different woods out there flying under the banner of willow and poplar which may be very different from one another. I have not used European or Lombardy poplar at all so know very little about it.

Thanks Nathan. Good to know the quartered poplar is holding up. Although like Conor, it seems there is a general preference for a slab cut poplar for the back at least.

I'm going to keep researching... Thank you both for your guidance.

if this piece winds up in a chest of drawers, i'm ok with that!

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I would imagine that poplar is usually slab cut, only because of the way the trees are converted into planks at the sawmill. As it's not that desirable as a wood, usually used for construction, painted finishes, furniture carcasses etc. There probably isn't any need for the mills to waste time sawing it into quartered wedges, which would be more effort and wasteful for them, but not bring in any more money. Slab cut planks, being wide, make it an ideal resource for cheap cello wood.

This thread is kind of heading the way of the other one on slab wood being the devils work. If you've already bought all your wood, why not just use it, rather than constantly worrying if it's going to split or not? Otherwise just sell it and buy some decent maple instead.

Endlessly worrying isn't going to result in anything getting made.

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Just looking at this thread again. I had one of my cellos show up in my shop for appraisal that had a two piece, quartered black willow back and quartered ribs.15 years old, no deformation or other issues and now on the list of my better instruments.

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On 8/30/2018 at 8:02 PM, Wood Butcher said:

Why would a beech neck bend any more than a maple neck?
Beech seems a pretty hard wood.

Beech is stiffer than European maple , and European beech i believe is stiffer than American beech and more stable . But beech is  supposedly dimensionally unstable in use which is probably why its not good for cello necks. It has historically been used for instrument necks though. So is debatable.

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Here's a  poplar  back fairly  well  quartered, with the faults I have seen from  time  to time.  I'm sure a less deeply flamed piece would be fine, although  I  just made a cello with planner ribs, one of which cracked straight  through in the bending. These flames really can send  the grain plunging straight  down. I can push the corner  of my business  card a full 8mm in to these shakes.

20190709_142620.jpg

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Conor, that photo illustrates the problem really well. Thanks for that!

I recently thicknessed two sets of poplar rib stock. One was quartersawn canadian poplar, the other slab cut tulip poplar. Handling them side by the side, the slab cut set feels much more resilient. The quartersawn stuff feels downright floppy. I don't know to what degree this is because of the species or the grain orientation, but I'm leaning towards not using the quartersawn stuff at all.

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11 hours ago, Joey Naeger said:

Conor, that photo illustrates the problem really well. Thanks for that!

I recently thicknessed two sets of poplar rib stock. One was quartersawn canadian poplar, the other slab cut tulip poplar. Handling them side by the side, the slab cut set feels much more resilient. The quartersawn stuff feels downright floppy. I don't know to what degree this is because of the species or the grain orientation, but I'm leaning towards not using the quartersawn stuff at all.

As has been discussed before there are many species of the Salix and Populus families sold commercially as Poplar. I have seen cotton wood from Western Canada sold for instruments and would definitely not use it myself while tulip polar is actually of the magnolia family and in my experience is the densest and heaviest of all the commercial "poplars".

I suspect the species accounts for the difference between your two sets of ribs not the sawing.

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On 7/9/2019 at 9:27 AM, Conor Russell said:

Here's a  poplar  back fairly  well  quartered, with the faults I have seen from  time  to time.  I'm sure a less deeply flamed piece would be fine, although  I  just made a cello with planner ribs, one of which cracked straight  through in the bending. These flames really can send  the grain plunging straight  down. I can push the corner  of my business  card a full 8mm in to these shakes.

20190709_142620.jpg

Geez Conor that's nuts. Nice for a flat piece of furniture but I couldn't imagine bending or carving this stuff. The poplar I have (pictured above) is halfway between quarter and slab - the light figure has a sort of quilted look. it reminds me a little of the cello you posted awhile back. 

 

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