Seeking Advice on Repair Project

[gbaker]

I acquired a damaged Craigslist bass just to work on.

Please understand this is a project, if it turns out, great, if not, well there is the experience. AND I saved some aspiring, unsuspecting DB player a lot of grief as there is plenty wrong with this bass.

There are several questions in the text below and would appreciate any advice and insight that any experienced bass craftsman (or woman) can offer. I would also be interested if I am doing things in the right order.

Sorry this is so long but I wanted to get it all out at one time. Thanks.

I can’t seem to upload here so if you want to look at the patient in the rough, have a Kodak moment:
http://www.kodakgallery.com/ShareLan...localeid=en_US

I have found a lot of good advice regarding attaching necks and gluing in general here:
Advice on gluing neck to body

Condition:
Bass – A 1974 Anton Schroetter 3/4 laminated student-grade German-export instrument . The seller said the neck was knocked off in a fall several years ago and that he didn’t attempt to repair it. Somebody did.

Neck Joint - I think it had been unsuccessfully repaired with wood glue. The block is softwood and has a flat top with a couple scored grooves (I think). The ribs at the pocket are a little split up but not bad.

The neck does not fit well in the pocket and I don’t see how it EVER did. The top plate is about 1/16” higher than the block leaving a tapered space between the neck butt and the block shelf. The button is mostly there but delaminating. The neck at the toe matches the button height.

Fingerboard – Is ebony and appears to be not too badly warn; shaped with 1/8” camber. Loose about 4" at heel.

Body – Some delimitation, damage edges, and at front at pocket due to neck trauma. Structurally sound.

Bass bar – Appears to be separating from the top for about 2” on the north end. Hey, I wanted experience.

Sound post area - The sound post, which was in-place, was set both too far south and at an angle with an edge digging into the top, there is a moderate bulge at the top 1“ south of the bridge foot. A round liner on the back inside appears to be a factory installation.

Other parts – Neck looks like oak or hickory, but seems straight. Peg box and scroll are sound. Saddle and nut are good ebony. Replace tail wire w/ cable. Replace bridge - warped and stands 6 5/8 “ high. End pin will do.

The plan:
I have never done hide glue before so I have started to set up shop for hot gluing. Ordered threaded rod to make the 60 spool clamps needed to reset the top.

Repair steps:
1. Read Traeger again.

2. Figure out the intended neck joint. There is no real mortise (you know, a pocket with cheeks), no dovetail, no good glue surface, just a flat shelf. The grain of the neck and the block are at 90 degrees. End-grain glue, the shredded button in shear and a little help from the rib ends are the only structural components of the neck joint. Is this typical for this grade bass?

3. Figure out the anchorage. This joint has been wood glued before. I am inclined to not rely on glue in tension and to bolt the neck to the block like Matthew did on his corner-less bass. Removable is nice. Or fill in the sides between the ribs with wood, to form a cheek to glue to? Anyone?

4. Figure out the neck joint angle. Maybe increase the angle to raise the strings at bridge to about 6 3/4” Glue in a tapered hardwood shim to fill the gap caused by the high front.

5. Dry fit the neck to check fit and bridge height.

6. Remove the top plate. First drill a lower and upper small pilot hole to realign with. Clean up glue.

7. Remove, clean glue and replace the bass bar. New or reuse?

8. Inspect the bulge caused by the sound post. Maybe add a pad, maybe large enough to add mass to the area as Traeger suggested for ply basses?

9. Reset the top.

10. Re-glue the fingerboard. Remove or just re-glue end?

11. Patch the delaminating top plys at the pocket and elsewhere. Where to get matching wood / finish?

12. Attach the neck.
13. Attach the machines. Polish or not?
14. Reset end pin.
15. New tail cable.
16. New sound post.
17. New bridge – adjusters.
18. New strings.
19. Adjust nut.
20. Evaluate setup.
21. Finish touch up, trim.

As I said any advice is appreciated. Thanks, Gary.

[simonwilmer]

Hey , Id concentrate on refitting the neck , if the top and back are still glued then Id clean up the neck joint and reglue , if you want to see a real bad neck block check out my "Cracked Top" thread in the Set Up and Repair forum , you can tidy up the top and back laminations last . take it slow and you will be fine .

[arnoldschnitzer]

Start by cleaning all the old glue off the neck and joint. That is a normal neck joint, but is missing the small trim strips. You will probably need to glue thin strips of wood to the sides of the neck to make it wide enough. Then you'll need to chalk-fit it into place, being sure to get the pitch and angle right. Every part of the joint needs to fit right, including the sides, button and bottom. Once you have it aligned and fitting, glue it in with hot hide glue. But you may want to first tackle the bass bar repair, as handling a bass corpus is much easier with the neck off. Good luck!

[gbaker]

Simon - thanks, I see what you mean by ugly block. Did you finish the project? Results?

Arnold - thanks for verifying the joint is of normal design, I am used to furniture joinery with a lot of mortise cheek area. I guess there is a safety factor in making the joint strong enough to hold but weak enough to fail to prevent worse trauma damage. I see where the trim is missing. I will just clean it up, shim it, fit it and glue it. As you suggested I will first do the inside work with the neck off.

[simonwilmer]

I missed the loose bass bar in your list ,
Im no expert, but taking on a ruined bass has been the best way to learn bass repair as far as Im concerned , but it is an expensive pursuit , time consuming and demanding ,
I am happy that I got the top sorted , that took around six mnths , I have a fresh spruce neck block ready , but I think I will be making a neck also as the original isnt that nice , and...the fingerboard is warped ,
take it slow and carefull and I really think its best to stay with the traditional methods , the masters got the design(s) right .

[gbaker]

Like a boxed chocolates, you don't know what you have until you bite in. I found bad, bad glue.

I started removing the top to get to the loose bass bar. Found a weak place on the C. It popped nicely - for about 4 inches and stalled at the braces. Tried cold knife, hot knife, wet knife, sharp knife. Basically the problem was that the joint glue was stronger than the lamination glue and the sometimes the wood. Ugly. I will spare you the pictures.

I now know the top was removed before and I suspect it was replace with either contact cement or full strength hide glue as that glue was transparent. Spend a couple hours playing with hot glue and putting top chips and seam cracks back together. Not too bad considering, but glad it is a project bass.

The bass bar WAS loose about 2". But I don't know how. Glued with some kind of plastic glue - like had been used on the neck. Again the glue is stronger than the wood. Tried heat, steam (afraid I will damage the glue lines in the top), and vinegar (helps where exposed, but it won't in flow past the edges). The bass bar is breaking (fine) but the glue line is holding like a bulldog.

Any ideas? Thanks. Gary

[Jake deVilliers]

The hot melt glue they use to assemble those basses should go plastic at about 150 degrees. If heat won't do it you can always remove the bass bar with plane and chisel.

Good luck!

[gbaker]

Originally Posted by Jake deVilliers

The hot melt glue they use to assemble those basses should go plastic at about 150 degrees. If heat won't do it you can always remove the bass bar with plane and chisel.

Good luck!

Hot melt glue, ya say! You inspired me to put more heat to it. A WalMart clothes steamer and a wide blade putty knife to transfered the heat to the edge did it.
Thanks Jake,

[Jake deVilliers]

I haven't been to China to watch them putting them together but that's what it looks like to me.
Glad you got it off.

[gbaker]

Back on my bass repair project, I have a new bass bar roughed out and ready to chalk fit. I matched the curve of the old bass bar. I have five deep-throat clamps ready for the gluing.

The old laminated top is kind of limp - like an old dish rag. The top standing alone has lost much of its crown. Clamping the new bass bar on the top seems to put the crown back in nicely but not so much warp that the top cannot eventually be refitted to the ribs.

For good contact I found I needed a backer caul with a complementary curve to the bbar. This I made from a sturdy chunk of oak. The top gets squeezed between the bbar and the backer by the clamp pressure.

Here is the problem:
How to do the final chalk-fitting for a good full contact glue joint if the bbar is clamped (as it must be) to the top?

Thanks.

[simonwilmer]

If it was my bass Id be thinking about making a new solid top , more work sure, but your in the middle of it all and you will use the same tools to put the top back on , look around for some nice quarter or close to quarter cut Western Red Cedar planks .
just my opinion after all .

[fdeck]

Just a quick note about threaded rod, I found it for a really good price in the electrical dept at Home Depot. It's used for hanging things from ceilings in commercial installations, and comes in 8 foot lengths.

[gbaker]

Originally Posted by simonwilmer

If it was my bass Id be thinking about making a new solid top , more work sure, but your in the middle of it all and you will use the same tools to put the top back on , look around for some nice quarter or close to quarter cut Western Red Cedar planks .
just my opinion after all .

Probably really good advice, Simon. Better to do a new top while I have the neck off and save the bass bar blank.

I have been searching for plans for carving a new top. Found these:

http://www.cljazz.com/bass/doublebassmaking.html

http://www.luth.org/plans/bowed.htm (#29)

Does anyone have any advice concerning these or other available contouring specifications or carving plans?


Thanks.