DIY

I would make some metal rods to insert in the holes left in the hollow plastic. Epoxy those in place on both sides to reinforce the joints which will have stress on them. I think that is the only chance you have of repairing broken plastic like this with little surface area to bond. You could look around and find some nails or something to cut up.

Glues are fucking useless unless you have a large surface area to bond. Headphones don't use ABS, too brittle. The use polycarbonate on the hoop that breaks and that doesn't bond well with glue.

Hot staples are an option because the embed steel wire into the plastic. These kits are cheap now and very common in automotive plastic repair because glue is universally useless.

https://thistothat.com/

Glue guide!

Maybe try JB-Weld? Idk if super glue will hold up here.

• fix the pieces in their intended position (maybe with a droplet of epoxy)
• bring out a dedicated soldering tip (you won't be soldering with it any more) and 3D printer filament of the same plastic
• weld carefully with a low-temperature iron, in a well ventilated place (maybe outdoors)

Gloop gets used in 3d printing. It physically welds the bonds together on a molecular level between 2 plastics.

If the adhesive route fails, it looks like there are replacement parts available, but your mileage may vary when it comes to the source. Not seeing anything official, but ebay has a few hits: https://www.ebay.com/itm/204942975498

Might also try just calling Sony support, but iirc their support is fairly shit.

If it’s ABS (which most thugs are) try methyl ethyl ketone to melt it back together.

Just a dab of MEK will melt the plastic, but it evaporates/dissolves quickly. Once you apply it press the pies together firmly for a few minutes, then let it cure for a while after that. The bond should be as strong as it was from the factor. Then if you want apply some JB weld for extra strength.

I bought a cheap Temu plastic repair welder (melts in a little metall pin) - they actually work and the results are surprisingly strong.

I'll be honest, you're probably not going to be able to fix those to a degree that I'd trust. Some headphones are reparable and have replaceable parts, and that isn't one of them. I've had really good luck with Audio-Technica and Beyer Dynamic in that department, but most of their more sturdy and repairable headphones aren't very portable.

UV Glue will fix that no problems, and the glue will be stronger than the underlying plastic.

Superglue sprinkled with baking soda creates incredibly strong bonds. But you'll need to add it all around the seam to make a thick layer.

I also recommend first scratching the plastic with sandpaper so that there's something for the glue to hold on to.

That looks like toast.

3D printed replacement parts might work. If you have a maker space around you, you might be able to find someone to help you with the drafting/CAD.

I've done some awful things with various 2-part epoxies, maybe try one of those with a piece of dowel in the square holes? Not sure exactly what you have to work with there but that might give you a little extra support from inside while your glue of choice just has to keep the rod from slipping. Start with one a little larger than the holes and sand the sides flat until it fits with a little extra space, add glue, press together, let it cure.

For bonus points, you can scratch up the inside of the plastic with a rolled-up piece of coarse sandpaper or something to try and give the glue an extra foothold.

Try layering several times with super glue and tissue paper.

physical reinforcement is a good suggestion lots are coming up with. If it's not too late, I'd recommend doing that with something that dissolves the ABS instead of an adhesive. ABS dissolves readily with a few solvents, like acetone. Get physical reinforcement in place, and IF you do not need any bulk filler, just use a solvent like acetone to literally melt and repolymerize the plastic back together. As long as there's no new gaps or new voids, the physical reinforcement should leave it stronger than the original. At least after all the solvent evaporates away.

If you need gap filler or bulk reinforcement, two part epoxies are definitely the way to go, though make sure to use something quite flexible or it'll just crack off the next time you drop them.

As others have said, copious amounts of super glue or epoxy. Pro tip for the super glue is to sprinkle baking soda on it to speed up the cure time.

This is a tough one, mainly cause of the strains experienced in that position. If you're daring, maybe try some acetone to "melt" and refuse the plastic. I don't think an adhesive is going to be much help unless you cake it in epoxy, and reinforce the stress point.

Not sure i would use a plastic stapler/welder for something like this with small electronics but it is for plastic ... If you're careful it might work long term. Just be clean and accurate and don't leave pointy bits that could cut you. The staples need to be trimmed after and it would be best to melt more plastic over it probably.

If you're up to a bit more complex of a job, I have files for headphone bands to replace the whole hinge and band with either 3D printed or cut metal.

3d printed can be done with any printer either as is or flat and then shaped with an oven to specific designs.

Metal needs only a dremel, drill, and sandpaper and can be made out if sheet steel from any hardware store. Bending is done by hand or 3d printed jig.

Both use 3m screws to be adjustable but can be glued in place if prefered.

Ouch, I used hot glue for mine but its not great at holding to the surface, I just had a massive surface to make use of and pretty much made a ring of glue around the break. Doesn't look like yours would work with that sadly.

So, probably don't go with hot glue.

5 minute 2-part epoxy. Buy the individual packets rather than the bottles so ya dont get solidified wasted bottles.

Loc-Tite Plastic Bonder has worked well for me in these situations, but sometimes it just doesn’t seem to take well; other times it holds better than the original plastic does. Worth a shot?