Double Bass Scroll repair?

[eh_train]

I am thinking of buying a Czech ply bass, as a second/ "beater" instrument. At the moment, however, it has everything above the nut separated from the bass (i.e., the pegbox is broken off).
All the parts are intact, however, and there is an intact "lip" of about 7/8" on either side of the pegbox bottom where it used to join/overlap the top of the neck (this is where the strength would have to be in the repair).

Assuming it can all be reglued neatly, I want to know whether the best DIY repair would be hide glue alone, hide glue along with wood or metal dowels, or a different adhesive. I understand that hide glue is usually preferred because it's soluble/reversible, but in this case I'm primarily looking for strength. Also, this bass was originally inexpensive, has been well-used, and the chances of anyone putting significant money into further repairs seems slight.....

 

[Eric Jackson]

Being an inexpensive instrument, it's probably not a candidate for a neck graft, which is the best (and most expensive) way to fix a broken-off pegbox. Next best is probably a whole new off-the-shelf neck, which still requires fitting and top removal and is therefore also expensive.
There just isn't a dependable, cheap fix for this problem that I'm aware of. I guess you have little to lose by attempting to glue the original bits back together. I'd use hide glue. I wouldn't use a white glue of any sort because they are too plasticy, don't allow intimate contact between the pieces being glued, and tend to creep over time. Maybe there's another resin glue of some sort that would work, I don't know. Dowells across the seam might help, but only if they're tightly fitted. I wouldn't use anything metal. Up here in the Great White North (eh) where we are, the temperature variations would result in a metal fastener or dowell constantly expanding and contracting and constantly "working" the joint, rather than helping to hold it secure.

(By the way, I have a Hofner on loan from Heinl's right now, pretty nice bass.)

 

[Bob Branstetter]

Being an inexpensive instrument, it's probably not a candidate for a neck graft, which is the best (and most expensive) way to fix a broken-off pegbox. Next best is probably a whole new off-the-shelf neck, which still requires fitting and top removal and is therefore also expensive.
There just isn't a dependable, cheap fix for this problem that I'm aware of.)

Eric has it right with the exception of the statement about having to remove the top during a neck replacement. The top seldom has to be removed for this proceedure.

 

[anonymous0726]

With PC-7 (http://www.right-tool.com/pc7epoxypaste.html) you could glue the bass to a building and have your great-grandchildren tells stories about their nutty forefather (in the presence of the aforementioned sculpture).

I'm not sure if I'm kidding, but if the neck is pretty much a loss anyhow I would probably consider it.

 

[eh_train]

Ray,
I'm (only somewhat) disappointed; I thought your link would take me to an actual picture of a bass glued to a building!? I guess the manufacturer hasn't considered this use, as yet...

 

[Eric Jackson]

I've used epoxies on different occasions for various jobs other that bass repair, and never thought very highly of them. They always seem very thick, which is ok for a joint with gaps to be filled, and they don't seem to set up hard, they tend to stay a little soft like white glues. Any glue that will creep is not very good for a joint in shear, like a broken pegbox.
What do pro high end cabinetmakers use for gluing hardwoods these days?

 

[anonymous0726]

I feel a little silly with this, but:

PC-7 sets up really, really hard. The surface is kind of on the porous (sp?) side. I guess it would be like a grey version of the lava rock that people scatter beneath their shrubs. It is thick to work with.

The greatest testament that I could give would be a repair that performed on a floor ashtray (anybody remember these?) that had a very fine, ornate handle made of pot metal that had been broken right in the middle. The entire surface area could not have been more than 1/8" wide and less than an inch high. No gap to fill. PC-7'ed and it lasted under less-than gingerly use (had to show my repair off) for 4-5 years before the joint finally gave way.

 

[Eric Jackson]

There ya go, Paul. Stick 'er back together with epoxy, if it fails you can always use the pegbox as an ashtray.

Sorry Ray, couldn't resist...

 

[anonymous0726]

Now there's an idea! A bass scroll ashtray would be the ****! Cast brass?

 

[anonymous0726]

BTW, not being a luthier I don't really mean to pitch epoxy as the right way to do anything, but if one were to choose that path then PC-7 would be at the top of my list. You could glue a bookshelf to a wall and trust it. Take my advice concerning application to a bass with the cliche' grain of salt.

 

[Chasarms]

BTW, not being a luthier I don't really mean to pitch epoxy as the right way to do anything, . . .

IME, epoxy is the right way to do EVERYTHING!!!

I think you can get PC7 is a smaller quantity at many autoparts stores in a product called JB weld. At least, it sounds about the same in reading the discription. Many years ago, they had a display for it in some stores that was a soda bottle glued to a wooden board attached to lag bolt fastened to a golf ball, etc, etc.

To borrow a phrase of a favorite movie of my youth:

"This is glue. Strrrroonnng stuff."

I have used JB weld for dozens of projects and never had a single thing come apart. I'd certainly take my chances with it on the bass. My wife had a Volvo that she drove for a decade or so. By the time we junked it, the only parts still together were those I had JB welded.

I patched a radiator with it once for a "temp" fix. 60K miles later, the radiator started leaking again only for me to discover it was actually rusted through somewhere else and the JB weld was still holding.

These days I keep it around to glue the kids' toys back together.

I noticed you can get it in a 90 lb. can at that site. That would certainly open up a world of opportunity for the practical joke minded types.

 

[anonymous0726]

That sounds like the display that I first saw for PC-7. I think on the display that I saw (about 1986-7) had the golf ball, Coke bottle, and a small wooden shelf assembled with PC-7 and then mounted on the side of the bottle with the stuff. The guys as the store would hand you the contraption and dare you to try to break it apart -- short of smashing the bottle itself, of course.