This instrument has been sold.


restoration of an unstable and much damaged Bohemian bass

This bass came into the workshop in the summer of 2006. It had lived the previous 40 years with one player, who unfortunately was not able to use the instrument nearly enough, as too often the unstability problems with ribs and back had pulled the bass apart. The bass was to move on to a new owner, with a view to making it more usable in the long run. Here I present some of the damage and earlier repairs, then my repairs and changes.

The belly had an integral bassbar, not really a bassbar at all, but rather a long lump left in place while the rest of the belly was carved hollow. This practice was popular between about 1870 and 1930 as a means of saving production time, and as the Bohemian instruments tended to be made quickly for little money in return, such shortcuts were common. Related problems are weak sound production, cracking (as this element provides relative stiffness parallel to the grain, suddenly weakening on either side), and arching collapse.

From the outside, the belly seems to be in better condition. This is illusory, as many cracks and old, weak repairs riddled it. Note the gold surrounds of the f-holes; this was done some decades earlier, probably with nail polish, and was also added around the scroll and the belly edges. There was some on the back as well.

A problem common to most of the eight back brace ends (there were four braces, usual for a flat-backed bass); glue fractures as seasonal widening/narrowing of the back overcomes it, and ribs are forced from the back due to lack of clearance at brace ends. This 'plywooding' of the back with perpendicular grain orientation of the braces is a long-standing problem of this sort of instrument, whether it be a viol, guitar, or bass.

Similar to the back, the large expanse of the ribs is always in motion with changes in humidity. A stiff, cross-grain cleat like this cannot possibly hold for years, and plainly it has come loose, as did all the other 4 like it.

The back of the instrument was heavily damaged, especially in the area of the upper kerf bend where a lot of deep scraping had gouged the wood, lower edges (straightpins had been used as nails to hold these in place!), and there was a hole near the middle. An attempt to re-varnish was also evident here.

The outside of the upper rib, shown from the inside above this image, was several times glued and not aligned properly. There were similar long cracks along both lower ribs and some smaller cracks on the other upper rib and one C bout.

Here the lower belly edge was previously 'doubled' - a common repair as edges become splintered through several removal/re-gluing cycles - but in this case the added spruce was all coming loose. Again, as with most previous repairs, this is owing to cross-grain orientation and seasonal wood movement.

The neck had been broken several times in the same place, and was most recently stuck together with a maple dowel (hammered in through a hole in the fingerboard), epoxy (very loose and wobbly), and a pair of brass screws. Not very comfortable for the thumb...

And here's one side of the scroll. The tuner shafts were of punky maple, cracked and worn beyond safe use, slipping in their gear collars. The upper side seems to have suffered some earlier damage after which someone did a bit of re-carving... this I smoothed and re-varnished.

The scroll and tuners after repairs. The new tuners are turned from old (approximately 40 years aged) dogwood, a light but very tough material, then dyed black. The gold paint has been scraped away, the wood varnished as little as possible, and the tuner plates cleaned and modestly re-worked.

The hole near the middle of the back I carved out from the inside, grafting in a piece of maple with the grain slightly askew to 'knit' the extended crack together, and leaving the new maple projecting outside the back. This was then carved level inside and out. A strong repair if done well, but often a source of misery, if the patch is improperly fitted.

Cosmetic elements aren't my primary interest, so this hole repair isn't invisible, but should be solid for the life of the bass.

Here I've put the back and ribs together again after replacing all the braces. The ribs are lined with linen, a too-seldom seen precaution from centuries ago which helps unstable and thin wood survive seasonal changes and moderate impacts. A new spruce top block replaces the original guitar-foot end of the neck, as this provides a more solid anchor for the neck and upper ribs. The braces have channels cut at intervals, allowing for some 'breathing' of the back between winter dryness and summer humidity. This is a new approach, to me at least. I've never seen this done with basses, though it is sometimes the practice with better guitars.

The belly is graced with a new, properly shaped and tuned bassbar. This measures seven-ninths of the vibrating length of the belly, has a considerable mass in the centre to help sustain belly vibration, then tapers quickly to provide less resistance for vibrations moving out towards the bar ends. Most old heavy cleats have been removed and replaced with linen and hide glue. Edges have been properly doubled (restored to original thickness) where needed.

A close-up of the middle, or soundpost brace of the back, showing the carefully tapered end and a tie-down of strong linen and hide glue to assist keeping it in place. I've experimented a little here, as I've only rarely seen linen used in this way. One place was on the bassbar-side lowest brace of this very instrument - this was the only one of the eight brace ends to stay reasonably well stuck to the back.

And at last the finished product. The bass sings far louder and more clearly than even I had anticipated, and my own hopes were very high. These ultra-light (strung up, it weighs a mere 20.8 pounds!) Bohemian basses are typically rather thin, relatively delicate, things to be taken care of vigilantly. They can ring like bells, properly set up and maintained. Leather bumpers protect one side from floors. With new ebony fingerboard, new bridge, all the old damage tidied up, this bass should perform for many years without serious trouble... so long as it avoids the prairies in winter. Even then, dampits properly used (wetted daily, squeezed out well in a towel before use, zipped into the case while not being played and avoiding sources of direct heat) should help prevent seams opening and other damage due to shrinking. Some time after the bass sold, I converted the neck such that it can be removed for transport, and also adjusted for string height using an Allen key. This change further improved the sound by a small portion, making it respond a bit more quickly. Such conversions, if stable and well executed, can save bassists a lot of money as airlines continue to take advantage with increasing oversize luggage fees. Having the neck separate in transit also eliminates the potential for it to be broken off by baggage handlers - an all too common occurance, as these workers seem to have a sort of hatred of musical instruments.

gerard@luthier.ca