material for Cello (rib/side)

[Ray Kahler]

After 3 successful violins, I am preparing to build a cello and finding materials is a bit more challenging. Bruce Ossmon's book, Violin Making, offered a successful hint for rib/side material. Using 2 layers of quality veneer, in a glued "sandwich" provided nice appearance and good sound quality. A cello however, would require 3 layers and I am reluctant to sacrifice sound quality using this technique. Does anyone have an experience with this? Local merchants in AZ have plenty of front and back material but not the 2mm thickness required in a cello.
Thanks
Ray Kahler

[Michael Lewis]

There are many good sounding instruments with laminated sides, some are very expensive and well regarded. Stacking veneers is a good structural idea but you need to make forms for holding them in place while the glue sets and cures. Vacuum clamping works very well for such projects.

Many veneers are about .020" (.5mm), so for 2mm thickness it would require four layers, and at that thickness veneers are quite flexible and easy to form to shape. Much easier to form the veneers than to bend solid wood. After the glue has cured the parts will be quite stiff and should be light weight if you get it right. Get your veneers and go for it.

[Joshua Levin-Epstein]

James Ham makes Basses and Celli with laminated ribs, a maple/silk/maple sandwich. He does this to minimize the typical cracking found with traditional construction. He has information on his website as well as some articles in American Luthiery. His instruments are well regarded.

www.hamstringsmusic.com

[Bill Raymond]

Joshua, you left out an 's' in that link: it's hamstringsmusic.com

[Ray Kahler]

Thank you all for your responses, I'll probably go with the laminated technique. I anticipate cracking will be less of a challenge for me because I got to practice on violins with more severe curves.

I'm making and refurbishing violins (and now a cello) for children who cannot afford to rent or purchase and your suggestions help me to do it better, getting more "bang from my buck."
Ray Kahler

[Bryan Bear]

Ray, Is your issue finding thin material for the sides or is it bending? It sounds like you are laminating because you haven't found a supply of wood the correct thickness. If so, have you considered finding someone to resaw and thickness the sides for you? If you are trying to stretch your dollars for this worthy cause (and good on you for doing it!) it may be cheaper to buy some nice but inexpensive maple lumber and find someone sympathetic to your cause to resaw and thickness to 2mm for you. You may even live close to an MIMFer who would like to help.

[Craig Bumgarner]

I prefer epoxy to any water based glue for laminating. Water base glues hydrate the veneer a lot and it takes weeks for the moisture to flash off. Warping of the final laminate was much more of a problem with water based glues. The WEST brand epoxy I use can be unclamped in 3-4 hours and is fully set in about 8 hours. It has a much longer open time than any of the water based glues which helps given the complications of application of the glue and getting pieces aligned and clamped. A short nap foam roller does a nice job of even spreading.

Vacuum bagging works good for backs, but I've found clamps and cawls best for sides, on guitars at least. Getting a complicated shape like a side bagged up on top of the mold and keeping everything lined up while pulling the bag down is nerve wracking. It require a fair amount of setup, specialty equipment and practice, at least that was my experience. Clamps and cawls are simple and soothing by comparison. Just need lots of them. Concave cawls will help spread the load of a single clamp. I can apply glue and clamp a guitar side in about 20 minutes. Doubt I could do it any faster with a vacuum.

If you want to get into laminating backs, vacuum is the way to go, especially if you are molding a violin back shape. I mold violin shaped backs for some of my guitars, vacuum is very good for this.

Poplar veneer is a good wood for the inner ply(s). Readily available, cheap, wide, glues well. Certainly Wood in Aurora, NY has a wide selection of veneer, including some thicker than standard veneers. Sometimes a 1/16" or 1/20" veneer with the grain 90 degree from normal is just the thing for getting the thickness you want. Being turned 90 degress will it will bend easily in spite of the thickness and will give the outer layers some grain reinforcement.

[Craig Bumgarner]

Keep in mind laminated sides are usually more time consuming and expensive to make than solid.

[Dennis Duross]

I've been laminating sides as a 3-ply:

[inner wood (@0.05" thick)]
+
[1/64" baltic birch plywood (oriented 90 degrees from the inner and outer lams)]
+
[outer wood (@0.05" thick)]

The finished sides end up a little under 1/8" but I plan on going thinner---just wasn't sure initially whether there'd be any telegraphing and wanted to play it safe.

Nothing against poplar as an inner ply, but the aircraft-grade plywood means your inner ply is birch, if that matters to you.

I'm using Titebond Extend, which has a little longer open time, and it dries crispy.