Wednesday, September 22, 2010

back pain in old violins

This old dear has dried out. I sometimes think I know how he feels. The centre joint on the back has opened up completely- and that is a tricky repair in itself to do nicely because the curved surfaces are so thin- but it has dried out and warped in the process. Wood changes shape and size with moisture changes, so the pieces no longer fit the perfect book-matched joint that the maker cut with a jointer plane.
What I've done in the picture is pre-clamp the pieces while I undertake preliminary rehydrating of the wood, prior to gluing. If this doesn't make the joint disappear, the back will have to come off and be re-joined.


  1. But if the back comes off, will it fit back onto the body? Sounds tricky to me.

  2. How do you go about re-hydrating such a delicate instrument? Tricky, indeed!

  3. Hi both, sometimes the back or belly will shrink more than the garland (sides or ribs arranged around the edges) can cope with, and that's when a plate or a joint will split. Sometimes this can be relieved just by separating the plate from a rib at the side, then gluing up again. The rib will then sit a little further into the overhang than it did though, but it won't be pulling the plate outwards. In this case the gap is too wide just to do that, so I'm using clamps to re-train the wood while I introduce controlled moisture locally just by laying a damp rag on it!
    Taking a back or belly plate off is a brutal but not difficult process (unless you get it wrong!) and gluing it back on is helped by using special clamps that help even out the pressure while you are madly adjusting rib position....