Voice coil glue

Epoxy stands heat and is the current standard.

Preheat the voice coil slightly, apply a drop of epoxy with a toothpick, give it a whiff of hot air which will make it "more liquid" , spread it where needed and remove excess, both with a fingertip.

Wash hands with warm water and regular soap.

Let it cure overnight.

That said, loose turns mean either a manufacturing defect or an abused speaker, neither means future reliability.
 
Sometimes the basket frame is in the way.
I used a curved syringe. You can find them at medical, veterinary, or some hobby supply sites.
 

Attachments

  • curv_syringe.jpg
    curv_syringe.jpg
    6.2 KB · Views: 318
Years ago, an alternative to epoxy was also available: UF glue (urea/formaldehyde): similar uses, same twin syringes dispenser, but IIRC UF had better temperature withstanding properties than commonly available epoxies, probably thanks to a higher Tg and crosslinking degree (needs to be checked).

Nowadays, this type of glue doesn't seem to be available anymore, probably because of environmental concerns, but if you can still find some, it would be worth making a quick and informal comparison between the two varieties (not difficult: place two drops side by side on a hot plate, and compare the hardness as you increase the temperature).
Note that ordinary epoxy is not especially health or environment friendly, as it contains a good proportion of bisphenol A
 
Epoxy stands heat and is the current standard.

Preheat the voice coil slightly, apply a drop of epoxy with a toothpick, give it a whiff of hot air which will make it "more liquid" , spread it where needed and remove excess, both with a fingertip.

Wash hands with warm water and regular soap.

Let it cure overnight.

Very good advice about washing hands.

Even better is to spread the warmed epoxy with fingers dressed in a nitrile glove. Epoxy resin dermatitis is a really nasty condition. Some folks get it by using epoxy just once, others may use epoxy for years until finally succumbing. Either way, an individuals sensitivity is unknown until it is too late.

I have in the past used epoxy a lot, and prefer to save up all those little epoxy jobs to do on the same day to keep any possible exposure down to the absolute minimum.

Don't get me wrong, epoxy is a superb material, but I have seen first hand what epoxy resin dermatitis actually does to the skin.

Just saying .......