On 4/14/2020 11:36 PM, Jeff Liebermann wrote:
On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW

That's what I use for gluing problem plastics. Seems to work with all
the hard plastics and some soft (flexible) plastics. It's a
cyanoacrylate adhesive, with some hexane added to soften the plastic.
Note that it's not very good at filling gap. With flexible plastics,
it does well if the glue joint is very thin and therefore flexible.
With a thicker glue line, it will crack and eventually crumble.
snip

Jeff,

Thanks again, I tried the Loctite above based on your recommendation and
the price and it worked great, exactly as you said - it is a great glue
for close-fitting parts! I added a 3/4" wide strip of aluminum cut from
a rain gutter and screwed that into place around the joint for extra
support, covered that with black tape, used the headphones several
times, problem solved and it's not too noticeable. Thanks for your
detailed reply.