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.

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

https://thistothat.com/

Glue guide!

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.

• 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)

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.

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

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

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.

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

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.

Try layering several times with super glue and tissue paper.

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.

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.

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.

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.

Acetone can join ABS because it is a solevent for that particular plastic and will mix the two treated surfaces at the molecular level. It would be wise to add some additional material in the hollow area such as an epoxy putty (jb weld as suggested elsewhere), but it should create a stronger bond between the broken pieces.

Whatever you do, don't break that wire, it's nearly impossible to DIY repair.