Not for a Coupe, but for my youngest son's Hyundai i10, where the rear bumper has become separated from the rear wing by virtue of the "joining strips" breaking away from the edge of the bumper after a small accident, see first pic below. There is other damage towards the bottom of the bumper also (a "tear" in a flat section).

The pic is from an eBay seller of a bumper I was thinking of buying, but has the same damage. The seller suggested that a "plastic weld" might work, but I'm not sure if that meant some form of glue, like JB weld, or those little metal "staples" that you heat up and melt into the plastic and the cut off the "stalks" (see second pic).

I've seen some neat repairs made usings these staples, and perhaps the "right angle" ones would work to reattach the "joining" strips, but on the other hand the staples might melt all the way through or just not melt into enoigh plastic for a proper join. The other damage to the flat section looks easy enough to do from the rear using the regular "curly" staples.

Does anyone have any experience of either JB weld (or similar) or "hot staples" for bumper repairs? The Hyundai bumper seems a liitle thinner than a Coupe bumper, which might make a difference...

Not an answer on the staple weld thingy, but…..

There are quite a few mastics that are used in the building trade that would definitely stick those bits of plastic together

I’ve used this on loads of things where I couldn’t get a mechanical fixing and it’s never failed, the name is quite apt

https://trade.evo-stik.co.uk/sites/...t/TDS00269-sticks-like-shit-adhesive.pdf

Cheers Jamie

I would give JB Weld a try. Not sure about the 'Sticks like ...' - I've used it for bonding flat surfaces, also CT-1 is similar and IMO better stuff. But they both stay flexible & if the bond is under tension I think it would fail over time.

Yeah, "Sticks like..." mentions most things but not plastic. Seems like an epoxy resion is needed. There are a few options all with similar reviews (mostly good, but still several that say no good) and I was leaning towards JB Weld.

Plastic weld is heating up and partly melting the two surfaces with something like a soldering iron and using something like a cable tie for the extra plastic to melt onto and weld the two things together.
If you have a soldering iron, have a practise with melting a couple of plastic surfaces and then using a melting cable tie to weld and join those surfaces.
Once soft, the plastic can be moved/pushed/manipulated across the crack to make the 'weld.

I'm not very technical, so that's the best I can explain it, sorry.

I understand. I've seen the results, can be invisible after subsequent prep and painting...

I'm not sure how well an araldite type adhesive would hold up. It possibly could be too brittle, but equally one of the mastic type glues might not grip well enough if the plastic is a greasy type.

One adhesive I do think would hold is Plexus. It's been a fair while since I used it so can't remember the product code, but hopefully there aren't too many choices.

However one thing that stands out for me is the complexity of the moulding around the bumper mounting tabs - could the shaping be deliberate to allow the bumper cover to unzip in a crash; pedestrian protection?

I will look into Plexus, thanks. You could be right about the "unzip" feature. Chances are that in an accident any glued (adhesive) joint would just come apart again anyway, which is fine. I just want a repair that will hold up to everyday drivng including motorways without having the side of the bumper flapping about in the wind, and without regularly remaking a join with clear tape on the outside (I think it's designed for clear plastic greenhouse roof panels or similar?)

Helicopter tape perhaps?

I'm reasonably sure the Plexus will do the job and probably survive the car . Bits I do remember from using it is that it shrinks slightly when it cures and i seem to recall a bit of heat while it goes off. Try not to use clamps too aggressively to get the shape and position correct, only to help locate the tabs if that makes sense?

The body shop that repaired a bumper for me, used a plastic welding method. From what they explained it must have been something like this with plastic welding rods & special filler.

https://www.polyvance.com/video/nitrogen-hot-air-welding/bumper-repair-with-hot-air-plastic-welder

This was impressive but the most impressive thing they did was paint a flexible rubber boot spoiler.
Still struggle to believe how that worked, flexible spoiler but the paint never cracked or splintered.