adhesiveepoxyplastic
I have a tube of bisphenol two part resin I'd like to use to repair headphones with a broken band. Problem is the band is plastic. Can I use a BPA resin to bond the earphone back to the band? I ask because both parts are plastic, and I don't know how well BPA plays with plastic. I also have JB weld which I know does NOT play well with many plastics.
I can also grab any relevant adhesive if there's something you think would work better.
Some sort of 2 part epoxy should hold up pretty well. Araldite is a common brand in the UK. For best results, try to remove the old glue so the bond is to the plastic itself, scuff both surfaces with sandpaper, then clean with something like alcohol to ensure the best bond. Allow to dry before applying epoxy. It's important to use the specified proportions of resin and hardener (usually 50:50) and that the two are well mixed. The epoxy should cure at room temperature or as specified, but once fully cured it will hold up under fairly extreme temperatures. It is also waterproof and resistant to most chemicals.
Be sure it is only applied to surfaces intended or materials disposable. It usually is impossible to remove once cured except by grinding away.
Besides epoxies, polyurethane based adhesives work well also. The two part versions are stronger but the more common one part formulas work quite well too and are more convenient to use. Such adhesives can be found in sizes anywhere from small craft quantities up to large tubes of construction adhesive by the case. Note that not all construction adhesives are polyurethane based.
Forget trying to glue it, repair it some other way. "McGyver" it.
Like maybe buy a lock hasp of appropriate size and use the staple, which is the piece that the lock shackle would go through (see picture). Sorry I could not find a picture of just the staple.
Screw the staple to the speaker body and the staple hole would rest in the base, aligned with the hole in the base. Use a nut and bolt to secure it, with washers and bushings to take up any slack. paint it black to match and only you will know it is there.
Or find some other alternative way to rig it, as glue is likely to disappoint you.
Best Answer
Epoxy is not a bonding agent; it is a filler. Use something that is called plastic cement, or melt the pieces together. Epoxy only works well for bonding if the surfaces are rough such that the epoxy can fill the voids on each side of the bond. Epoxy's internal strength is high, but it does not attach well to anything, so it can generally be pulled right off its host surface. The only way to attach something to a smooth surface with epoxy is to drill through the surface and let the epoxy ooze through those holes and spread out on the other side; like a molly bolt.