Double Bass Why is glue dissintegrating from my URB?

[N. Kentucky Bass]

I have a c1920s Czech bass that was recently restored. The luthier removed a coat of bad varnish and an undercoat of white paint. Lots of sanding, puttying cracks, repairing structural issues, applying coats of French polish -- the works. The result was great and the bass sounds gorgeous.

So now, about four months after project completion, I have discovered glue and putty has dissintegrated from some of the biggest cracks, and notice minor separation between some wood joints so it would seem that the bass was not "fixed" as I thought.

What is causing this? There have been no physical or temperature shocks to the bass. I play normal pizz. and am doing bowing exercises for about 15-30 minutes a day.

I'm going to look into another luthier, but what should I beware of to avoid this in the future? I appreciate any insight as the URB world is new to me.

 

[reedo35]

Putty to fix cracks? I'm no luthier, but that just does not sound right to me. Maybe some of the other pro luthiers will have some comments on this. Sounds like your guy took the cheap route, and now you're paying for it.

 

[Silversorcerer]

I'm going to look into another luthier, but what should I beware of to avoid this in the future?

Well, finding a luthier is a great idea, and regularly reading this forum will help you avoid future mishaps. FYI, wood and hide glue are the principal materials in double bass repair. If something else is suggested, beware.

 

[Eric Rene Roy]

...I have discovered glue and putty has dissintegrated from some of the biggest cracks, and notice minor separation between some wood joints so it would seem that the bass was not "fixed" as I thought...

It might be Deft. It's pretty common to use as a filler...but only on small, shallow spots (and in no way in place of actual wood). Any significant build up tends to fail in a short ammount of time. Deft was the talk of the town in it's day...but it's use is becoming less and less favorable.

 

[Bob Branstetter]

It might be Deft. It's pretty common to use as a filler...but only on small, shallow spots (and in no way in place of actual wood).

That is a new one for me. Deft is a brushable nitrocelulose lacquer and very handy for refinishing woodwork inside the house where spraying is impractical, but i had never heard of using it as a filler on instruments before. I know some guitar repairers who use sanding lacquer for filling in cracks in clear lacquer finishes after cracks in the wood have been repaired. Sanding lacquer is somewhat softer than regular lacquer and can be shaved down cleanly with a sharp razor blade on a flat surface. I wouldn't think that Deft would work as well for that purpose.