Critical error sanding/truss rod

[dazmond]

Calamity! I was finish sanding and exposed the truss rod under the 5th fret where it's set deepest. Clearly I either miscalculated my neck thickness at some point or got carried away shaping the neck. It's a single curved rod set in epoxy in the method of Bruce Johnson. I can't think of a way this is fixable. Ideas? Can it be functional? Will it blow out the back? Poke my eye out??

It's my first build and has been a very long and slow process, I am devastated to be at this point and now maybe have to start over. At the very least maybe the fretboard is salvageable?

 

[Bruce Johnson]

Calamity! I was finish sanding and exposed the truss rod under the 5th fret where it's set deepest. Clearly I either miscalculated my neck thickness at some point or got carried away shaping the neck. It's a single curved rod set in epoxy in the method of Bruce Johnson. I can't think of a way this is fixable. Ideas? Can it be functional? Will it blow out the back? Poke my eye out??

It's my first build and has been a very long and slow process, I am devastated to be at this point and now maybe have to start over. At the very least maybe the fretboard is salvageable?

There's no need to be devastated! No danger of explosions or flying shrapnel. The truss rod should still function just fine. The only caution is to be careful about tightening it too much in the Reverse direction. That could push it out of the back of the neck a little bit. Tightening it in the normal Forward direction, the rod is pushing inward (upward, from the side). If you've built the neck well, you should never need to turn the truss rod in the Reverse direction anyway.

Finish up the bass. Enjoy it and learn from it.

This is really just cosmetic, a birth mark on your first bass. Nothing to be ashamed of. A reminder to be a little more careful with your engineering on the next ones you build. I will admit to having done this several times, myself.

 

[Flying B]

Yes we've all been there! Chances are nobody except you will ever even notice that especially with that grain.

 

[Beej]

Yep, I've been there a few times too, but without the benefit of the embedded epoxy, so mine ended up being picked for parts instead. One I tried to repair with carbon fiber and a veneer a la Ken Parker, but I learned enough to know I was not able to have success in that method.

 

[Reedt2000]

Those who understand the engineering have already spoken. All I have to add is you can hide it with paint

 

[dazmond]

Well thanks for the reassurance everyone, especially Bruce!

 

[Jazzdogg]

Calamity! I was finish sanding and exposed the truss rod under the 5th fret where it's set deepest. Clearly I either miscalculated my neck thickness at some point or got carried away shaping the neck. It's a single curved rod set in epoxy in the method of Bruce Johnson. I can't think of a way this is fixable. Ideas? Can it be functional? Will it blow out the back? Poke my eye out??

It's my first build and has been a very long and slow process, I am devastated to be at this point and now maybe have to start over. At the very least maybe the fretboard is salvageable?

Could have been much worse. Consider yourself the lucky recipient of a learning experience!

 

[basshack]

Been and done that once too. It’s just part of the journey. In our guitar shop we have a saying. If I can’t be repaired in under 30 minutes it’s a feature.

 

[micguy]

There are people that use "back straps" to counter string tension on necks, and those end up on the surface - they are more effective that way. The way to make a truss rod most effective is to have it as near the back as you can - on basses, truss rods are almost always used in tension, in that mode the truss rod will work just fine, even if it's visible - it's simply a metal back strap who's tension you can vary at that point.

 

[Dirk Diggler]

Are you sure that's rod or epoxy?
You used dark epoxy?
Or a dark metal truss rod?

That could be an odd bit of Wenge grain perhaps?

I think a magnet might help figuring out if it's metal.

The other thing good thing is Wenge is incredibly strong.

I think the key to building is being able to recover gracefully
from challenges.

 

[dazmond]

I don't want to recover from problems, I want perfect execution the first time 100% it's both the bottom of the bar and a tinge of epoxy where the rod starts curving up

Are you sure that's rod or epoxy?
You used dark epoxy?
Or a dark metal truss rod?

That could be an odd bit of Wenge grain perhaps?

I think a magnet might help figuring out if it's metal.

The other thing good thing is Wenge is incredibly strong.

I think the key to building is being able to recover gracefully
from challenges.

 

[JamesGrant]

The wood will darken considerably once you apply wax/oil/varish. It might not look very noticeable at all.

 

[mpdd]

maybe this is why we strip the painted necks with razor blades and not sand paper at work

 

[Bruce Johnson]

If you want to hide it visually, you can always carefully mask off a narrow black stripe down the back of the neck, and spray it with some tough black paint. Like polyurethane or epoxy. Then people will think that you installed a Carbon Fiber Backstrap. Which the cool Advanced Luthiers do.

 

[Bonkersville]

I don't want to recover from problems, I want perfect execution the first time 100% it's both the bottom of the bar and a tinge of epoxy where the rod starts curving up

Perfect execution. That's a goal. But rarely reality.

My first ever build was a neck through guitar that was designed around a double cut lp. As a confident engineering student I designed and made a double acting truss rod myself. I was surprised how well the instrument turned out. Not perfect, but nice for a first try.

Well, after 2 months or so the welds in the truss rod gave in and I had to blow up the neck. I was certain that a heated knife was a great way to remove the fingerboard. Back then the internet wasn't filled with the wealth of information we have today.

Anyways the board removal went less than ideal and I ended up removing a lot of wood from the neck shaft. I got it back together with a thick new 9 mm fingerboard, some maple strips to widen the neck shaft, an off the shelf truss rod and some carbon strengtheners. The guitar is somewhat playable, but the neck is too narrow and definitely not as pretty as the original was.

That was 20 something years ago. And I have yet to reach perfect execution in anything I do. Maybe one day...

 

[Dirk Diggler]

Well perfection as a goal for the first build is not a wise target.
And apparently not achievable this time.

As I said to me the most important aspect of building is being able to correct problems
efficiently. They will always pop up even with years of experience, sorry to say.

My only other thought is removing the fingerboard, remove the rod and epoxy.
Then you can route out a skunk stripe and rear mount your rod again, like FSO bolt ons.
Or once you glue in the skunk stripe you can route the rod channel again from the top perhaps a little shallower this time.
Then add the rod and re-glue the fingerboard back on.

Take your time and measure your situation, how deep does the rod require?
And how deep is the neck at this point?

Keep in mind the only depth you need to add is right behind the rod.
Even an 1/8th" in Wenge should be fine, well certainly better than current.

 

[dazmond]

Perfect execution. That's a goal. But rarely reality.

Well perfection as a goal for the first build is not a wise target.

I don't I really mean that... except it's an actual real problem in my life. Not starting projects that I know will be functional but not perfect. Or finishing projects and then living with a lingering fear that somewhere down the line it will fail and then I won't know how to fix it.



Thanks for sharing this story, I appreciate it.

Perfect execution. That's a goal. But rarely reality.

My first ever build was a neck through guitar that was designed around a double cut lp. As a confident engineering student I designed and made a double acting truss rod myself. I was surprised how well the instrument turned out. Not perfect, but nice for a first try.

Well, after 2 months or so the welds in the truss rod gave in and I had to blow up the neck. I was certain that a heated knife was a great way to remove the fingerboard. Back then the internet wasn't filled with the wealth of information we have today.

Anyways the board removal went less than ideal and I ended up removing a lot of wood from the neck shaft. I got it back together with a thick new 9 mm fingerboard, some maple strips to widen the neck shaft, an off the shelf truss rod and some carbon strengtheners. The guitar is somewhat playable, but the neck is too narrow and definitely not as pretty as the original was.

That was 20 something years ago. And I have yet to reach perfect execution in anything I do. Maybe one day...