Filling upper horn of hollow body with epoxy to relocate strap pin?

Hard to say without knowing the mechanics of that specific instrument. Can you share a photo or two? What are the top/back/sides made from? How big is this horn you need to fill?

Epoxy is roughly the same density as water, so if it took 4 fluid ounces to make a solid fill big enough to put a screw in, you're only adding 4 ounces in weight. Not bad. You could mix in some microballoons to make it a little lighter in weight, but with any additive like that you're also increasing viscosity and at some point it won't flow enough to do the sort of self-leveling you'd need for this.

 

With this kind of shape you can solve both problems by attaching the strap to the headstock rather than a button.

 

Use a shoestring or something alike as a hack to give it a try. Through the hole of the strap, between strings and headstock behind the nut then round and tie a knot.
It balances differently from a regular button to button strap and usually works well on hollow bodies with short horns.

 

It's worth a try. You also won't hurt your elbow in this position. If you don't like it, back to the drawing board.

 

Bass looks awesome congratulations, I would probably try to talk to Warwick first, if you do want to go for epoxy I would drill a small hole where you want to put the strap button and load the epoxy from there with the bass vertical tuners to the floor, load the epoxy, then put the button in and let it go off, loads of blue tape and planning, you need to be 100% on how it’s all going to work do a test with the epoxy and a screw in a piece of plywood the same dimension as the piece on the bass, think about it a lot prior to doing the work and try to foresee any problems
Good luck

 

@andruca: I had an Epiphone Jack Casady and suffered the same issues. Neck dive and the upper part of the body tending to tilt itself towards the floor. The Jack Casady and your Warwick are obviously not the same basses, but they are of similar construction and both have the strap button on the back of the neck.

After some deliberation I ended up drilling a hole in the upper horn and placing a new strap button there. I did not reinforce the wood in the horn, and it ended up working out fine. Mind you, I am no Pete Townshend.

Surprisingly, moving the strap did not help the dive, and (oddly) made the tilt even worse. Ended up selling the bass as it never felt right.

Good luck!

 

Sometimes people put strap buttons on 335s on the upper horn. I have mostly seen them screw pointing towards the bridge if that makes sense. I imagine this bass has multiply maple and poplar sides and top. That is how a 335 is made at least.

The screw will probably hold as long the pilot hole and screw are not too destructive. I have seen them underneath the horn too with the screw pointing towards the ceiling.

The edge causing the arm pain is the worst. I had a Hofner that did that. On guitar you can get used to it, but on bass we tend to rest our arms there.

The neck dive would probably be best solved by a different strap. Neck dive is the reason the upper horn on a pbass sticks out further than the bottom apparently. Strap button moves and weight is redistributed thus no neck dive.

 

EPOXY THROWS OFF A LOT OF HEAT as it cures.

I would be very leery of pouring a puddle into the horn.

Epoxy Chemistry - Understanding WEST SYSTEM Marine-Grade Epoxy

"Exothermic heat is produced by the chemical reaction that cures epoxy. The amount of heat produced depends on the thickness or exposed surface area of mixed epoxy. In a thicker mass, more heat is retained, causing a faster reaction and more heat. The mixing container’s shape and the mixed quantity have a great effect on this exothermic reaction. A contained mass of curing epoxy (8 fl. oz. or more) in a plastic mixing cup can quickly generate enough heat to melt the cup and burn your skin"

 

Otherwise known in history as the "Hootenanny" position, as on Early Fender basses, and string ties on the neckstrap to tie them under the strings behind the nut for the folk guitar players.

 

Take a little wooden wedge that will fit through the f hole and fish it through a pilot hole in the horn. Screw the strap button into the pilot hole on the horn while holding tension on the wedge. I think the screw would pull the wedge tight against the interior of the horn. This way the screw would have more wood to sit in. You could even pre glue a wedge into place.

 

I'm not a luthier, but I make and restore antique reproduction furniture, wooden airplanes and play bass.

Can you install a plywood or solid stock backer where you want to relocate the pin? This would eliminate fully filling a potentially resonant area, curing heat issues, and weight from the epoxy.

It could easily be located by coating with wood glue, a strip of CA around the edges to grab immediately, the simply drilling the screw hole.

 

I vaugley remember someone who posted with pics just as suggested, but I just can't seem to find the posting

I would think this would be a good approach

 

You can heat epoxy two part once mixed to make them flow better but be advised heat usually accelerates the cure time.