Building a Double Bass: The Ribs and Linings–Part One

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Bending and Installing Bass Ribs and Linings: Part 1

Gamba-corners versus Violin-corners

When I built my first bass, ten years ago, I built a bass rib bending “iron” of heavy aluminum pipe, and it worked acceptably for that bass, primarily because it was a “gamba-cornered” bass:

my first bass

Gamba-cornered bass: no recurve at the corners.

The gamba-cornered basses derive their name from their earlier predecessors, the viols. (Some people still refer to them as “bass viols”.)  The violas da gamba were a medium-sized viol, intended to be played in a sitting position, gripped between the knees, like a cello without an end-pin. Their corners had no recurve, so the basses with similarly shaped corners are called “gamba-cornered.”

But this bass, in addition to having a removeable neck, will be a “violin-cornered” bass, with sharp recurves at each corner. And, as it turned out, the old bending iron just wasn’t going to work. So I improvised by clamping a piece of 4″ ABS pipe to the workbench, draping a wet rag over the rib in progress, and “pressing” it with a clothes-iron. Surprisingly, it actually worked, just not all that well. I could get a rib flexible and roughly bent the way I hoped, but then had to quickly clamp the floppy rib into the mold and let it cool and dry there, and regain some rigidity.

Again; it actually worked… just not very well. It was a very frustrating process, and clumsy, much as if I had never built a bass before. I can tell that, before I build another bass, I need to build a better bending iron…and maybe streamline my mold a bit, as well– this one is a real tank, and inconvenient to use, as I did not use good foresight regarding where clamps would fit, so as to actually use the mold. (sigh…)

So, when I last posted photos (16 months ago…things have been busy) I had the mold prepared and the ribs ready for bending.

Bass mold with blocks installed and shaped

Bass mold with blocks installed and shaped. The mold will be removed, leaving only the blocks as part of the finisnhed Bass.

 

Bass ribs ready for bending.

Bass ribs ready for bending. The blocks were not shaped yet, in this picture. I ended up removing that neck block and replacing it with Spruce.

 

Bending and Installing the Ribs and Linings:

I always install the center bout ribs first–usually called the c-bout ribs. When the glue has dried on the c-bout ribs, they can be trimmed to match the outer curve of teh corner blocks, and the upper and lower ribs can be installed.

The C-bout ribs have been installed

The C-bout ribs have been installed and trimmed. I used salvaged ABS pipe for clampling cauls, and any sort of clamp I could lay hands on.

 

I really will have to improve my clamping arrangement  before building another bass. Probably will have to make major improvements on the mold, too.  I bend the upper ribs one section at a time, and clamped them to the mold to cool and dry, before making the next bend:

Beginning to form the upper bass-side rib.

Beginning to form the upper bass-side rib.

 

Bass side upper rib fully clamped

Bass side upper rib fully clamped.

 

Clamping nightmare.

Clamping nightmare.

 

More nightmares!

More nightmares! Those pipes tended to roll, throwing off the clamps. (sigh…)

 

And still more nightmares!

And still more nightmares! those sloping surfaces encouraged the clamps to slide off.

 

But finally, things began to shape up, one step at a time:

Both upper ribs in place

Once both upper ribs are in place it begins to look roughly like a bass.

 

Upper and C-bout ribs installed

Upper and C-bout ribs installed and trimmed. The bass is clamped to a table-top, so it looks huge, but it is only about 42″ tall.

So, the next step is the lower ribs; but I was uncomfortable handling the mold with the unprotected ribs, so I will install the upper and center linings before attempting to turn the mold over so I can install the lower ribs. The linings stiffen the edges of the ribs, as well as tripling the gluing surface presented to the front and back plates.

I installed the upper linings before trying to up-end the bass and install the lower ribs and linings:

Lining installation

The linings begin as straight strips of weeping willow, as shown. I bend and trim them to fit, then attach with hot hide glue.

 

Bass side linings complete. Treble side glued and clamped.

I only have sufficient clamps to attach one side at a time. You can see that I have already installed the bass side linings.

 

Back with no linings, yet

No linings at all on the back side, yet…that will be the next step. See how thin the ribs really are!

 

Upper and center linings completed on front side.

Upper and center linings completed on front side.

 

That is all I am going to post for now…the lower ribs and linings are next, but I have to create a fixture that will allow me to turn the bass to a variety of angles in order to work on it. I think I have a plan figured out: we will see how it turns out.

Meanwhile, another project has arrived on my doorstep. A lady sent me a cello begun by her dad, but which was still incomplete when he passed away 9 years ago. My assignment: resurrect that dream-cello! It will have to wait until May 1st, I think, but I am anxious to get started on it. It is made of beautiful bird’s-eye maple and what seems to be Red Spruce. I hope it turns out to be a great cello. Looking forward to the challenge. 🙂

Thanks for looking.

 

 

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