Double Bass Homebuilt EUB build thread

[Videojunkie]

Finally received the jack and battery pack. They only spent three days in Amazon delivery purgatory which isn't too bad for this time of year.

I am hoping to get them installed this week, and then I can plug it in and see how it sounds.

 

[Videojunkie]

Catastrophe. Somehow the bass fell over, face down onto the carpet. No idea how, none of us were in the room. Of course it was under full tension when this happened.

The headstock broke right above the heel of the neck. I think I can squeeze some thin or medium superglue through the crack and fix it without resorting to drilling and pinning the sides.

 

[Jeff Siddall]

Oh no, sorry to hear that!

I agree though, if you can get glue deep into that crack than it should be stronger than ever, and hopefully hardly noticeable.

Good luck!

 

[Steve Sawyer]

Start with the thin stuff to allow it to wick into the crack, follow with some medium and immediately clamp. Cross fingers.

 

[Flamingo21]

Cross fingers.

We'll all cross fingers.

 

[Videojunkie]

This is the glue I have on hand.

 

[DoubleMIDI]

I‘m not sure that kind of glue does work well.
I got the recommendation to mix epoxy parts and heat them (maybe heat before mixing them) to make the epoxy much more fluid and apply it along/inside the crack. Clamp, remove residue epoxy and wait a day. I think that would hold better. Anyway, keep in mind that you can try only once with that kind of glues.

 

[Beej]

Ugh, I feel your pain. Seems like I can't hardly get through a build without a catastrophic event occurring somewhere along the way.

Epoxy can be good in these situations, but I like to use it when I can really be sure to get enough well into the crack. In this case, since you may not want to prise it open too far for fear of breaking it further, I think I'd wick thin CA deep into the crack and medium towards the opening (assuming medium can get in there). I'd forgo the accelerator, clamp it quickly and ambient moisture take care of the curing.

I also wonder if a couple of turned 1/4" purpleheart dowels in through the back of the headstock, running right through the crack might look like a beautiful, intentional custom detail.

 

[Flamingo21]

I also wonder if a couple of turned 1/4" purpleheart dowels in through the back of the headstock, running right through the crack might look like a beautiful, intentional custom detail.

The advantage of that is that it gives you much more gluing surface, plus you can more easily put glue in the narrow part of the crack.

 

[Videojunkie]

I also wonder if a couple of turned 1/4" purpleheart dowels in through the back of the headstock, running right through the crack might look like a beautiful, intentional custom detail.

I was thinking I have some brass rod left over...

 

[DoubleMIDI]

The problem with dowels are that they expand and compress at a different rate and direction with changing moisture and temperature.
Try glueing first. Take a second pair of hands to either apply the glue or hold the crack open.
If it doesn‘t hold, you can think about using dowels (even though I do not recommend it).

 

[Videojunkie]

Did thin ca glue in the small end of the crack, switching to medium for the thicker crack. Got good squeeze out, so I am pretty sure there's glue throughout the surfaces. (Which probably means that I used about 5x as much glue as necessary)

Now we wait... And cross our fingers...

 

[Videojunkie]

On a totally unrelated note, how long should I wait before stringing up the bass? Starbond says it should take 20 seconds to cure, but I'm concerned about the deeper parts of the crack.

 

[Jeff Siddall]

There is no right answer as curing is grey not black and white, but if it were mine I would wait at least a day or two unless you are under some kind of deadline.

 

[Videojunkie]

From the FAQ,

Starbond CA glues typically achieve significant bonding strength within 10-15 minutes. However, it is recommended to allow up to 10-15 hours for glues to reach maximum bonding strength.

So, overnight. Sounds about right.

 

[Videojunkie]

New battery pack. 4x the battery life (in theory).

 

[Jeff Siddall]

That's a pretty giant battery! Actually, based on Energizer Max battery specifications, the AAs should last about 5X longer but probably cost about the same.

 

[Videojunkie]

I figured with it driving 5 different preamps (eq, mic, 3x piezo) having a bigger battery would be a good idea.

The original plan was to parallel 2 9v. Don't do that by the way. Almost started a small fire.

 

[Jeff Siddall]

I figured with it driving 5 different preamps (eq, mic, 3x piezo) having a bigger battery would be a good idea.

The original plan was to parallel 2 9v. Don't do that by the way. Almost started a small fire.

I am curious how a pair of 9 V batteries almost started a fire!

When you say parallel, do you mean positive to positive, negative to negative?

 

[Videojunkie]

Yeah, positive to positive to preamp
Negative to Negative to ground. Ok for single cell batteries, not so good for 9v