A recent detour to the Dark Side - cello refurbishment (30 pics)

[Sperry]

While the occasional guitar and mandolin does cross my kitchen table, a friend dumped a pile of violins and one cello into my truck bed back in February. The last instrument, the cello, is finally done. Here are the pics and a little commentary:

The top popped off relatively easily. Stringed instruments use hide glue for many joints.


Someone tried to repair the top without removing it. I had to recrack the repair. Wood was missing. So I did the sensible thing when a free cello comes to the door: I sanded the edges flush, much to the amazement and consternation of true professionals.








Cutting a piece off my slab of Adirondack to make spruce cleats.






Gluing cleats using a lead weight. I used Titebond for everything except the fingerboard, top, and back.


These cleats were later shaved down.


The edges have been trued and I now prepare to mate the pieces. A little more than 1/16" was removed.


Ugly, but it is working. String tension is about 110#, and the longest crack just misses the sound post.


Now to try to "fix" the varnish, which proved troublesome. I used spirit varnish, thinned with denatured alcohol and tinted from a fairly old collection of pigments.




The back corner had major finish damage of unknown origin.

[Sperry]

These are the pigments I scored. Some of the bags have writing in German, I think. These were gifted from David Michie, the luthier who does most of the work for the Philadelphia orchestra.


One of innumerable attempts to get the varnish right.


Possibly the final buffing, after I decided the varnish was as good as it would get.




Cooking up hide glue.




A lip crack being repaired.




What I'd love is a Starret mm ruler with end gradations to get the projected hight of the bridge from the fingerboard ...




I delivered the cello yesterday and noticed the saddle had jumped out of the slot. It was too high, and the slot needed more work. So after playing bluegrass until 7:30pm, an hour after sunset the cello made it back to the table. I whittled the saddle lower, changed the profile, and squared up the saddle slot as well.


This morning the strings went back on. Works perfectly now. Tone is improved as well. Duh.








So that's it. A collection of mistakes, learning 57 ways not to apply varnish, and a lot of guesswork. The cello plays very well; it has action a little lower than spec (5.5mm / 8.0mm is spec, high to low strings, measured at end of fingerboard). The sound is fantastic. Far superior to a student cello. The guy who will sell it for us thinks it is now worth $800 to $1,000. It is a mid-1950s Framus 4/4 (full size) cello.

[rogthefrog]

That is super cool.

I see you poured some Bass. Did that increase the cello's low-end?

[Sperry]

Originally Posted by rogthefrog

That is super cool.

I see you poured some Bass. Did that increase the cello's low-end?

HA HA HA HA HA

TOOK ME A SECOND TO get it . . . wow, that is really funny, because I spent more than a few minutes trying to figure out why the lowest string, C, was so muddy. And I was wondering how you knew I was working to improve the bass.

Turned out to be improper saddle, the ebony thing at the bottom edge, as well as the sound post. And some back separation I had not noticed before getting the instrument under tension.