Stradivarius - Cool wood

Was it the special varnish? Was it the precision of his carving? What gave Stradivarius violins their special timbre? His varnish has been extensively analysed and although the exact recipe remains unknown, it was basically an oil-based varnish with sandarak (resin), madder root and colorants. But it wasn’t the varnish. Many strads have been badly worn over the past three centuries and most have been revarnished - apparently without adversely affecting their tone.

Stradivarius experimented with several different woods for his violins, but mostly went for spruce and maple - as used today. But his wood was different. At the time Stradivarius was alive, Europe was experiencing a mini ice age with long winters, short summers producing dense annular rings in the trees as they grew more slowly. That is why today the best violin wood comes from cold and semi-arid places - the lack of water makes the trees grow slowly and produce a denser structure. So it is likely we will never see the same timber again - our atmosphere has different pollutants, and our world is getting warmer, rather than cooler.

Drying time - long thought to be a factor, doesn’t appear to be the case. Antonio dated his instruments on completion. The annular ring pattern provides the date the trees were cut down - the difference is the drying time - usually less than 20 years.

But above all, what has struck those who have analysed Antonio’s methods, find that his violins are quite rough inside with varying thicknesses in the top and bottom plates - and perhaps that after all is the secret - by having an infinitely varied fibre length in the timber, every frequency has a chance to ring, along with its respective overtones.

Here is a fascinating insight into the structure of a strad

Cheers
Jerry

Pochette part five - linings

With the glue dry on the ribs it was time to separate the skeletal structure from the mold ready for the next step - lining the ribs with reinforcing strips to provide a greater glue area for the top and back plates.

This is essentially the same process as for the ribs themselves - soak some thin timber strips for about half an hour and then heat up the water pipe in the vise and with the tin backing strip, steam bend the linings at each end - I’m not sure if Neil Gow did it this way or if Antonio Stradivarius used this technique for his violins, but the concept of lining the ribs goes back a long way into the history of violin making.

I then clamped the strips in place against the inside of the ribs to dry so they would retain their shape. I held them in place with clothes pegs and a couple of spring clamps for the ends.

Here are some closer views.

The next step is to glue these firmly in position and clamp again until the glue sets.

After this I’ll shape the end blocks and start work on the top and back plates.

For previous entries on this topic see:
Pochette part four
Pochette part three
Pochette part two
Pochette part one

Cheers
Jerry

 

Pochette - part three: Bend it like Antonio

The next step in making my pochette, or travel violin is to bend the ribs. Last time I had cut them to length and width. I then soaked them in a tub of water for four days - yes it’s a brutal thing to do to timber, but that’s nothing to what was coming next.

The big question was how to bend the ribs around a fairly tight right-angle turn without breaking them. After a bit of reading around I decided I needed a bending iron and strap. You could spend a bit of money and buy them.

Here’s how I did it. I took a piece of galvanised water pipe and held it in the vise. I then cut the ends off a soup tin and then cut it up the middle so I could open it out flat with a pair of tin snips. Then I used a portable propane gas torch to heat the pipe - after making sure there was nothing flammable in the vicinity.

I then took up one of the ribs, made a pencil mark where I wanted the bends and positioned it between the tin and the hot pipe, keeping my hands clear, and then pressed it against the pipe moving it along about a millimetre at a time. You will hear a hissing noise and that’s a good sign - the water in the wood is turning to steam and steaming the fibres, allowing them to crush on the inside radius, while the water soaked outer ones remain flexible enough not to break - provided they are backed with the tin.

The result is a straight rib with two right-angle bends

And I then clamped the two ribs against the mold where it will gradually dry in shape over the next couple of days. The reinforcing strips will be bent the same way.

When dry I will glue them up ready for the top and bottom plate that still need to be shaped. More on that next time!

You can see earlier posts on this topic:

Pochette - second step

Pochette - first steps 

Cheers
Jerry

 

Toyota’s violin playing robot

Looking like a cross between star wars and I, Robot, this latest offering from Toyota plays the violin. While not the first violin playing robot, this one does hold the instrument in a traditional fashion and plays… well… mechanically. Actually the bowing arm is very good and could be a good teaching device to show how each of the arm joints should move when bowing.

As the commentator points out, this is less about the music and more about showing how far robotics has come in delicate articulation. The shopping cart shown later is definitely a taste of iRobot

Cheers
Jerry