Double Bass Neck heel crack, fingerboard modification, no budget...

[GretschWretch]

How is a syringe full of epoxy reversible?????

On a conventional neck, which the one in this thread now appears not to be, that break/seam should not be where it is. Unlike a neck removal or repairing an open table seam, that break should not be there and there is no need for it to reopen. That particular repair would not need to be reversible. Of course hide glue should be the first option, but if a stronger adhesive is preferred epoxy probably is the next step. Whatever adhesive is used, just be careful not to use so much that it seeps into areas it should not and complicates a full neck removal.

 

[turf3]

How is a syringe full of epoxy reversible?????

No, the OP is planning to use a syringe full of hot hide glue.

Even after the more detailed description of the neck joint, it still sounds to me like there's a significant chance that the dovetail is loose. If the glue can't work its way down to the dovetail, or even if it can and the dovetail has been mashed and deformed so the glue has to fill too much space, then the repair may just be moving the stress to the new dowel, which probably can't take it on its own.

But, it sounds like it's all reversible.

 

[Silverface]

How is a syringe full of epoxy reversible?????

??

I'm not using epoxy. That was a suggestion by somebody, but as I said in an earlier post the plan, as suggested by Upton is to:

Dry-insert a 1/2" dowel through the neck heel from the front (fingerboard off, obviously), extending about 1/2" into the fixed heel section. The only glue will be hot hide glue flooded into the existing heel joint (which was initially thought to be a crack). Then the joint will be clamped closed (but not over-clamped to avoid a dry joint) & hot hide glue injected into the open seams of the dovetail joint Only a couple strap clamps will be needed in addition to the heel clamp.

The fingerboard will be reinstalled after a bit more "fine-tuning" of the shape & the bridge reworked (or replaced).

 

[Silverface]

Even after the more detailed description of the neck joint, it still sounds to me like there's a significant chance that the dovetail is loose.

When I found the neck "slightly loose" that word was misused and probably misleading. The heel joint had opened a small fraction of a millimeter and with no string tension there was less than 1mm movement at the peghead. The hot hide glue I'll be injecting into the dovetail should take most, if not all the stress off the dowel, which hopefully will be serving only as "insurance".

As I mentioned earlier it would be physically very difficult fo me to handle removing the neck and replacing it, and I can't afford a new neck. This is a "make do" repair that the manufacturer believes will work fine. If it does, great. If it doesn't I'm not concerned - I may sell it as a "project" or try fixing it another way.

If I'm able to use it, great - but if not it's no big deal, as I never intended to buy another upright. It was essentially handed to me and I paid $300 just to help my buddy's daughter out. She simply wanted to get rid of it and I thought it'd be kind of fun to have. I got about 7 months of use out of it before it suffered a bizarre accident (and it really was one of those things that couldn't happen again in 500 years - or 5000)

But with my fixed income and physical issues I can only do so much. It is what it is, and the repair will work or it won't. I have no other options that are practical (given my situation) and reasonably reversible.

 

[GretschWretch]

Will a mere 1/2" of dowel into the fixed heel be enough to give the dowel a good "grip" against string tension?

 

[Silverface]

Whatever adhesive is used, just be careful not to use so much that it seeps into areas it should not and complicates a full neck removal.

10-4. I do guitar and mandolin restorations regularly and have been doing fairly extensive tech work - including some limited "string instrument" repair - since the 70's and I'm one that preaches "reversibility" - especially because I often work on valuable vintage pieces.

Will a mere 1/2" of dowel into the fixed heel be enough to give the dowel a good "grip" against string tension?

FWIW I'm also steaming the dovetail and immediately injecting hot hide glue into that joint as well. If the neck was a mortise and tenon type I wouldn't even think of using this dowel approach. But the dovetail joint is what should be taking the tension, with the dowel added for insurance.

 

[Silverface]

A short followup in case anyone is interested.

The dowel reinforcement of the "stacked" heel (I prefer to call it a "split" heel, terminology used for other instruments with similar construction) went very smoothly. I used a 1/2" maple dowel as recommended by Upton. This resulted in removing less than 4% of the heel and replacing that part with differently oriented maple.

The only slight hitch was cosmetic. Hot hide glue injection had to be performed at the joint, and it needed to be steamed first to loosen old glue that had obviously disbonded - so some finish was fouled and a small amount of surface chipping occurred. No big deal as I do instrument finish work regularly - it'll be patched and the entire heel coated with satin black lacquer (trying to restore the color just would not be worth the effort).

The re-shaped fingerboard with the Romburg Bevel removed works just fine (this was probably my favorite part as I got to do fine detail work with my seldom-used cabinet scrapers) and the new adjustable bridge was no more trouble to shape and fit than any other. The neck is a hair off-center but not enough to worry about (and there was no way I was going o pull the neck and do a full re-set - not on a bass I paid $300 for and will play maybe an hour a week).

But nothing I did is non-reversible if someone wants to go to all the effort in the future. So it's a budget "good enough" repair that works for me and can be improved in the future is someone feels it's worth it.

Last - my Kevlar/Nylon strings sounded better but still muddy, and the originals (which I found were Thomastik Spiro mediums) are far too stiff for my bad left thumb joint. I simply can't afford new strings or to experiment with multiple sets (like many folk/bluegrass players I always used "whatever is on it" strings!), but wanted to improve it a bit.

I found a used/near new set of Eurosonics in the classifieds and they work great! Very clear and full, nice sustain and growl, and easier on the fingers than any strings I've ever played. I REALLY got lucky with those.

So I ended up with a low-budget repair (but a reasonably qualified one) and have a nice, playable bass that meets my needs fine - and it can be "refined" further after I kick the bucket if a new owner feels it's necessary.

Thanks to all for your help, even those who thought the whole thing ridiculous (and that a $1500 repair on a $300 bass worth maybe $2k was justified. I still can't resonate with that....). There were good ideas proposed and cautions that if nothing else had me double-checking calculations and reconsidering procedures...before I said "F#&% IT !" and moved ahead anyway.....

 

[Silverface]

Checking back in after almost 6 weeks and a pile of 100 degree days - several with no AC due to electrical problems (thankfully fixed!).

After the repair I installed a near-new set of Eurosonics, seated, shaped/adjusted the new bridge and re-set the soundpost. The finish was a bit discolored from steaming the old gglue and injecting new, so I did some finish touchup in the heel area

The only work after the strings settled in were minor action adjustments. The repair is perfectly stable (more stable than I expected during the really hot days) and it plays/sounds great!

 

[Silverface]

Another check-in for both supportive folks and some with rather negative opinions as to the approach and work (neither of which I had much choice over is it was going to me repaired at all).

More hot/humid days, especially in August & September No issues & it's been very stable. A few typical action tweaks, but's that's it. The joint in the two-piece heel that Upton used in these earlier European-made versions has held perfectly, as has the reassembled/re-shaped fingerboard (which had been seriously broken - twice).

I loaned it out to a buddy to take to an outdoors bluegrass jam on a 95+ degree day. I'd bought a "Double Bass Buggie" wheeled mini-cart - makes it easier to move but does subject it to quite a bit of vibration, especially on grass. But he had no issues, liked the performance with the Eurosonic strings and said it easily equaled his old Englehardt in volume, tone and stability.

So I'm very pleased - for under $600 (including new adjustable bridge, buggy, 2 sets of Nylon and a used set of Eurosonic strings) I ended up with a bass that more than passes my initial expectations.

 

[Turnaround]

Putting a bolt through the heel seems like a simple way to approach it, and believe me many have tried that. The thing is, in terms of the real strength necessary to secure the neck in position, the bolt can't do it — it's not precise enough to maintain a good joint with the kind of stress the heel carries.

The real problem with a bolt through the heel is that the wood will expand and contractbwith humidity changes. The bolt won’t. Sobif the bolt is tight now and the relative humidity drops, the wood ill shrink and the bolt will no longer be tight. And if the bolt is tight now and the humidity increases, the bolt will crush thewood under the bolt end. Then when the RH drops the bolt will be loose.

 

[Silverface]

The real problem with a bolt through the heel is that the wood will expand and contractbwith humidity changes. The bolt won’t. Sobif the bolt is tight now and the relative humidity drops, the wood ill shrink and the bolt will no longer be tight. And if the bolt is tight now and the humidity increases, the bolt will crush thewood under the bolt end. Then when the RH drops the bolt will be loose.

Agreed - that’s one of the primary reasons I drove a 1/2 maple dowel from the front. As it’s made of the same wood as the neck it will expand/contract at the same dimensional rates & directions as the neck itself and the short section of heel it’s driven into (part of the block in this particular design.). Only a very small amount of original wood was removed when the hole was drilled and the dowel created a solid heel connection, removing the structural weakness of the split heel.

Upton uses a full-depth (front to back) heel in their current basses - it was something inherent in these particular Romanian builds. Apparently there are very few problems with them - unless some knucklehead (NOT me!) knocks one over on its face! since I had to reset the neck anyway I agreed with Upton’s suggestion to “unsplit” the heel to prevent future issues. And since I’m in my 60’s I figure if it ever DOES fail it’ll be one of my kids’ problems!

 

[Don Hergert]

Fwiw, metal does expand and contract too, but it does so with temperature changes, not humidity; it contracts with cold and expands with heat. So, with a bolt in the neck, there is a potential for:

the wood to expand and the metal to expand on a hot humid day
the wood to contract and the metal to contract on a cold dry day
the wood to contract and the metal to expand on a hot dry day
the wood to expand and the metal to contract on a cold humid day

Of course the rates of contraction/expansion of the wood and the metal could and probably would be unpredictably different.

Aside from my bass, I play a number of other metal-to-wood bodied instruments (multiple banjos, dobro) and weather can make a huge difference in tone. So far (~50 years) none of them have exploded apart though.

 

[Silverface]

Wow - over a year since my last repair update.

ZERO problems. I bought a Bass Buggy since it's tough physically for me to carry it around; the potential downside is that the only times I've taken it out have been to park jams, with it banging around through grass and dirt.

But it doesn't even get thrown out of tune much - and tuning shifts I chalk up to changes in temperature and humidity.

The black "stinger" (a guitar tech term most commonly used for hiding Les Paul headstock repair finish damage - which is VERY common!) hasn't cracked or wrinkled, and the upper neck heel joint (which Upton has since abandoned) hasn't opened back up or slipped at all.

And the fingerboard, which had been shattered and bent, was so bad many insisted it was IMPOSSIBLE to repair and that a new 'board - actually, a whole new neck - needed to be installed by a "bass tech", not a guitar/amp restoration tech who periodically works on string instruments (when I asked about replacement /boards).

Well, not only did proper planning, the right clamps, hot hide glue and guitar, uke, resonator, violin and mandolin restoration experience allow me to restore a fingerboard that hold up just fine -

But I was able to shave off the Romburg bevel (which made it physically difficult to play), but also carve the proper relief into it. The whole thing has held up SO well that a few experienced upright players have jammed on it for over an hour each and didn't notice the cracks until I pointed them out.

So toUpton Bass and those who were supportive through the project - thanks much!

And to the many who insisted it could NOT be done by a lowly "guitar tech"; required a certified bass tech, new fingerboard and probably a new neck; that my repairs would never hold; that carving relief could not be done with MY inexperience; and that I would be ruining a good bass....

...I hope your words are tasty.....and full of gristle and unidentifiable multi-legged creatures.

 

[1st Bass]

Well done!

 

[Silverface]

In case anyone is interested and hoping my repair worked out fine - or has been waiting with bated breath for me to post about the neck joint exploding....

It's been just short of a year since my last update, over 3 1/2 years since I repaired/re-set the neck the *first* time & pieced together/reshaped the shattered ebony fingerboard (removing the Romburg bevel that made it virtually unplayable for me and redoing the relief) - and 3 years since the more extensive repair of damage caused by a friend -

The whole thing is perfectly stable. There's not even a finish crack at the stacked heel joint, and the fingerboard is smooth as glass.

And it's been played FAR more than anticipated, including being borrowed by friends (who were curious how it would compare to their vintage Kays or Englehardts) for acoustic gigs and a couple of bluegrass jams (in *hot* weather!). I was very confident about the neck joint; less so about the fingerboard, as it was in quite a few jagged pieces when I got the thing. But over time and with more use the cracks, dyed filler and joints where chunks were glued together/smoothed out are even LESS visible - and if you close your eyes you can't feel a single one.

Those real upright players who have played it said it played/sounded as good as any of the basses they regularly gig with.

So for my $300 investment - plus hours of tech time performing repairs and reshaping the 'board - I'm pretty darned happy - hell, if it blew apart tomorrow I'd be happy with the amount of use it's gotten!

 

[1st Bass]

Nice epilogue!

 

[jlmorgan84]

I personally enjoy your coming back yearly to dunk on everyone who doubted you, please continue to do so