Copyright 2005-2006 www.jjsviolins.com
 
Cello Button Restoration » Back

Pic 1 -

This customer bought the fiddle several years ago, and knew that the lines in the varnish by the button could become serious. I saw her for a board dressing and mentioned that she should keep a close eye on them and sure enough, just a few months later . . .

This must be repaired immediately, the damage that will result when the neck tears out would be expensive and you will have to do all of the work described next anyway. . .

Pic 2 -

Remove the neck by making narow cuts first above the button, then along the ribs, making certain that your cuts go all the way to the back at the bottom of the neck sides. Then split the neck heel to it's depth with a stiff, sharpened pallet knife and a light mallet. Make sure that the neck is held ONLY by the end grain surface, then hold the instrument tight on the bench, ribs down and bump the neck lightly around second or third position alternating "E" (or "A") side and "G" (or "C") side. If you have released the neck fully, it will pop out with only a little effort, if it does not come out easily, go back and find where the side or bottom of the neck are still attached.

Pic 3 -

This is how clean the neck should come out, the glue on the head grain end will not resist very much. Look in the corners and you see no neck wood still stuck to the body- this is what I mean by being sure that your cuts go all the way to the inside of the bottom of the heel

Pic 4 -


This is interesting only in seeing the damage from the inside, the button is the strongest area of the neck joint, this neck was in much danger. Also you can see the cause. . . the sides and face of the joint were curved, the button was holding in the neck almost entirely alone, the button is strong, but you must have contact in the entire joint, tightest in the bottom corner and perfectly flat on the button.

Pic 5 -


This picture shows many things, the button was glued by holding it in place as the glue sets, time consuming, but really the best and quickest way that I know of. Then the reinforcement that you see glued to the button was set into the block. Notice how this was a wedge in two directions, down - so that as it is pushed into the block, it is pushed down onto the back and button (the button is reinforced by a mold discussed in Pic 7), and out- to keep those beveled edges tight against the edges of your mortise. Also in this picture you see the buildups necessary for the neck set. The sides of the neck heel, the inside of the mortise and the edges (the bottom is built up by the reinforcement in this repair).

Pic 6 -

If yous are setting the neck with the board on (I usually take the board off, it is usually wrong in some way, and if I am setting a neck, I don't want to set it to wrong measurements, but time constraints would not allow for this, I was given two weeks for this and almost made it.) a caul must be made and glued to the board. Put paper in the joint and use white glue. The guide that you see on the end of the board is one of a pair at each end of the board that a straight edge is placed against to extend the center line to the bridge and saddle area. The neck must be checked for center at the bridge position, saddle position, at the nut and at the neck. Establish a proper angle to center, to extension height at the bridge position and neck mensur with the end grain area of the neck and the face of the mortise, then establish the lay of the board, the center of the heel and the fit of the joint by first making the sides of the mortise very clean, then planing the build ups. finally, fit the button and sink the neck to a proper overstand.

Pic 7 -

This is the mold that I mentioned in Pic 4, I make it by protecting the instrument with foil and pressing body filler on with a plywood backing. Be sure to make it big enough to clamp on so that you have one less thing to do when you glue the neck in. Also, notice the wedge on the mold, this is adjusting the angle that the clamp puts pressure into the joint. You use a wedge to adjust this until the pressure forces the neck onto the face of the block as it forces the neck down onto the button. The pressure is on the back, inside of the purfling, NOT on the button.

Pic 8 -

Now the buildups are cut down and you can give your customer a positive delivery date and hope that the relief in their voice is anticipation of getting their instrument back and not relief that you're not going to botch the job. . .

Pic 9 -

The buildups on the sides are cut down to appear as part of the ribs except. . .

Pic 10 -
. . . There is usually one corner that does not quite meet the button, so you carve a small triangle as if it were neck wood and mold it gently into the rib.

Pic 11 -

With a small water color brush, you can paint in the grain lins and fleck and then with varnish color, bring it to match the color of the surrounding neck, so that when you varnish the neck, this triangle all but dissappears.

Pic 12 -

The finished heel, I use two basic layers, a ground that takes two or three coats to build up, then the varnish that is maybe five coats. This is made of a three to one mix of copal and shellac in alcohol and a blend of three powder colors, cassel brown, (a mineral color), a synthetic version of indian yellow and a very pure rose madder, ground very fine. (Kremer Pigments has all of this- Product numbers 41000 for the brown, 23350 for the yellow and 37200-b for the madder lake.).

Pic 13 -

Repairing the damaged purfling was slow- steam, moisture and massaging it with a thin knife, but the damage near dissappeared and the customer was quite happy as this area is very obvious to a cellist.