Double Bass top deformation

[Doug D]

I'm working on a newer (1997?) fully carved upright that took a fall. The face-plant did some understandable damage to the top which required its removal in order to repair.

I noticed that the top has, what appears to be some deformation or sinking in the area beneath the bridge/strings path (not as a result of the fall). In an area about 5-6" wide and starting just above the bridge running down the center seam and stopping before the saddle.

imagining this in a cross-section, it actually appears like the arching just levels off at this wide center line.

I'm wondering if top deformation is common or if perhaps it could have even been carved this way?

I've heard that over sprung bass bars can cause such?

any one seen this before?

 

[don leister]

I've seen a few tops and backs even that looked similar, american ones, that looked like they did the arch all around but sort of flattened at the peak, almost like they ran out of wood in the center to continue into a nice rounded peak.
Could the top be too thin on yours? Know how thick it is there?

 

[Doug D]

finally got pics.

you can see that the top actually seems to have moved past 'flat' on top and now even appears to be dipped in a bit.

wondering if it would help to wet or steam this area and place it in a plaster mold under weights for a bit?

any suggestions (other than scrap it)?

 

[farmerdude]

Bump... I currently have a similar situation with a bass. (carved)

 

[farmerdude]

This one is borderline basket case. Bass bar is unglued at lower bout. Actually there is a bad repair of the bass bar - someone put a thin piece of plywood about 6" wide UNDER the bass bar in this problem area. Still I like it.... its a huge beast (full size) and i'm gonna try to save it. Any ideas? Kind ideas

 

[bassics1975]

That is a bit extreme. Most tops will naturally sag a bit over time given the stresses that they are subject to but they usually stablize after a while and pose little/no concerns for further settling. In a case like this one, it may be time to visit the local luthier and have an estimate done. A sprung bar will usually pull the top down at the ends of the bar and leave the center in better shape. Judging from the picture above, there seems to be extensive deformation on both the ends and in the middle. To press the top back into shape, fix and cracks and refit a new bar will certainly run some serious money.

If it is any consolation, I too am refitting a bar in a carved Eastern European bass that I had in the basement (pardon the pun) since university. It would be too cost intensive for such a bass to have the luthier do the work so it is serving well as a personal project. If it turns out to be a complete disaster, no big deal given that it was not a good instrument to begin with and I had written it off many years ago anyway.

 

[farmerdude]

I have since taken the top off....you just never know what you are gonna find.....now in process of removing the bar and the huge patch..... then will have to decide what to do. Is it possible to press a carved top back to shape?

 

[bassics1975]

I have since taken the top off....you just never know what you are gonna find.....now in process of removing the bar and the huge patch..... then will have to decide what to do. Is it possible to press a carved top back to shape?

Absolutely. It is something that is done quite often when refitting a new bar (not in all cases though). A plaster cast is made of the top and hot sand bags are placed in the area that needs to be pressed-out.

That is quite an old bass you have there. I would be curious to know a little more about it. The bar and the patches don't look professional at all. These repairs could be contributing to the extensive sag from your first photo. With a bit of patience, those concernes could be addressed.

 

[farmerdude]

Thanks for the input Basssics......

I can tell you all I know....
Ive had (over the years) basses from the 20s and 30s - this one does in fact look older than that....I would call it a full size(larger than my 7/8)- huge lower bout - 43" string length, with no neck block. Interesting that it is the lightest of the 7 basses I own.....
The old repairs are very professional, but, repairs went downhill through the years and looks to end with the 70s wall panell patches and bad bar.... word was it come from the Ozarks so I blame the Missouri hillbillies
I received it from a violin luthier friend who will also help me in the process.....

For reference- first bass is 3/4, then 7/8, then this blockless wonder...

 

[ctregan]

I have since taken the top off....you just never know what you are gonna find.....now in process of removing the bar and the huge patch..... then will have to decide what to do. Is it possible to press a carved top back to shape?

Be prepared, there may be some horrific damage under all those patches. It takes a lot of time and patience, to repair a top, in this condition. Good luck.

 

[bassics1975]

It looks as though you have a late 19th century Bohemian or German bass. These 'blockless wonders as they are affectionately called, could be gems. I had one myself at one time and although it wasn't the nicest looking bass, it had a great sound. It would certainly make a great project bass. I don't think you could do any worst than what is there right now with those unsightly patches and what appears to be a bass bar of sorts. Good luck with the repairs!

 

[eh_train]

... repairs went downhill through the years and looks to end with the 70s wall panell patches and bad bar....

Quite a project! I have to wonder if the wall panel was attached using hide glue!?

Good luck,

Cheers,

Paul

 

[360guy]

It looks like a fun project. Myself, I would use a shallow gouge to remove most of the old patches. I'd be careful not to cut into any of the original top. If its hide glue a damp rag with a clothes iron over it will remove the little bit that's left quickly. If its yellow glue I'd use a scraper to remove the last of it.

My approach is to take big projects like these a "bite" at a time. It's like eating a huge Thanksgiving dinner...you can't do it in one gulp. Best of luck to you!