Stiff adhesive to plug up a small gap and provide structure in plastic?

[fuzzybabybunny]

I've got a pair of expensive IEMs and the plastic housing has cracked in a very annoying part. They're not under warranty.

The part of the housing that holds the cable plug is cracked. If the wire gets torqued in the direction of the arrow in the photo the cable plug socket gets pulled right out of the housing (pictured). Unfortunately this is a naturally high-torque point.

So what adhesive can I use to repair this? It needs to be able to withstand torque, be ok for use around electronics and wires, and it needs to be able to fill in the existing 2-3mm gap and provide rigid structure like the original plastic housing.

- Two-Part Epoxy

Permanent. I'm afraid that if I use epoxy I won't be able to open these back up again, at least without completely destroying the housing.

- Gorilla Glue

Gorilla glue isn't very stiff. Because it's foamy I think it will torque apart easily.

- Standard Super Glue

Too liquid. Can't fill up gaps very well. And I've heard that super glue can give off fumes that might damage the delicate balanced armature drivers of the IEMs.

- Gasket Maker

Probably too flexible.

- Some kind of gel glue that dries hard.

In my experience Amazing GOOP has been able to harden and be pretty stiff, but I'm overseas and Amazing Goop seems to only be an American thing. Unfortunately standard silicone-based glues are probably too flexible for this application.

Any ideas?

 

[JulesMaximus]

I busted a mirror off my motorcycle and used JB Weld to secure the two parts back together. I really just tried this as a temporary solution as I had already ordered a replacement but it worked quite well and stood up to about 100 miles of use at speeds up to 85mph and the vibrations of a 150hp Ducati.

 

[RLGL]

Trial and error, all depends on the composition of the plastic

 

[Charmonium]

If you're worried about shearing force resistance when the socket is torqued, wouldn't you want something that is flexible. Things like super glue that dry hard tend to be very susceptible to shearing forces.

Also, are you sure you want to seal the connector under a layer of adhesive? I can't be sure from the photos (although they are very detailed), but it looks as if you could get away with applying a small amount of glue to either side of the connector. I don't know how much stability you'll add by sealing the connector in it.

Something like rubber cement should secure the connector to the housing and would probably be the easiest to remove.

If there are gaps that need to be filled, then a tiny amount of gorilla glue should work.

Don't know about what VOC's are used for either though.

 

[Paperdoc]

Exactly what type of plastic this is can be important. Polyethylene is almost impossible to glue to - has no good attachment points at the molecular level - but items like this are not usually made of that. Polypropylene is just as difficult. If it's polystyrene (model airplane plastic and other things), the old model airplane glue is ideal because it actually disolves the plastic at the contact area and blends itself with it to form a good bond. Sometimes getting that glue is tricky. I had to go to a model enthusiast shop to find it, and it was NOT on display on the counter. Local regulations had them keep it hidden until someone asked for it, to deter thefts and legit sales to glue-sniffers.

Krazy Glue - acrylic glues generically - are not going to work. This type does NOT fill gaps - it forms only a thin film and must have surfaces that are exactly matched. Gorilla Glue - well, the original type because they have broadened their lines - is polyurethane glue, and it will fill gaps, bond to lots of flexible materials, and remains somewhat flexible. If you use it, read directions carefully - it needs a tiny amount of moisture to catalyze the glue setting reactions, and it has to dry slightly so it's not very fluid before you can put the surfaces together.

If this is a polycarbonate type of material - "Plexiglas" or "Lucite" are common trade names, but they are slightly different - talk to a supplier of such materials about where to get the right special glue for this. (Not all items made of this polymer are clear.) I have used it to repair clear Lucite display cases, and it works very well. It really is a solution of that same polymer in the right sovent, so it disolves the edges you are trying to bond and blends them together with some of its own materials as it dries. Dries solid, makes a good bond with this type of plastic, and can fill small mis-matches in surfaces.

My "Old Reliable" is two-part epoxy, and I always keep the 5-minute kind around. It never sets fully in 5 minutes, but it does set much faster than the plain kind, so it shortens the time you must support the parts together as the glue sets. It does not bond well to polyethylene, but nothing else does, either. It does make a strong hard bond when set and will fill gaps easily. So, that, or model airplane glue IF your item is really polystyrene, is my suggestion. Or if it's polycarbonate, find that glue.

From what I can see in the photos, you still have the broken-off pieces of top over the connector. And it appears the main body is in two halves with a seam right though the connector mounting area. I have no doubt that the strongest approach would be to assemble the thing, add a bunch of glue around the connector, add on the two broken pieces and ensure they are glued to the main body and to the connector, and let it harden. But surely you would not want to try to disassemble that later! Alternatively, can you glue one broken piece to each half of the main body while it is disassembled, then let those set just like the two halves were originally made? After that you could re-assemble with the connector in place, and MAYBE add just a little glue along the edge of one half of the upper broken pieces so they are glued together over the connector, but not really stuck down. That way you'd have little hard epoxy (or whichever) glue to cut through later if you need to re-open the thing.

 

[EliteRetard]

Your best bet is epoxy putty. Most of the strength without the mess. It's just like two part epoxy, but in a play-doh like format (you kneed the two putties together). It will go exactly where you put it (and it can fill gaps). If you want to replace the missing chunk of plastic without it sticking to the metal connector, just place a trimmed piece of plastic tape over that part. For best results make sure the surface is clean (even finger oil can reduce the bond), and ideally rough it up a bit. Just as for computers, 90%+ IPA should be a good cleaner in this situation. As for roughing it up, anything you can get in there to help increase the surface area for bonding. Sandpaper, a rock, or even scrape in some slices with a knife if that's all you can do (and clean it again afterwards). Obviously epoxy isn't indestructible, so if you want the best chance (and don't mind the aesthetics) you may want to apply a thicker blanket that also goes over the broken edge and down the outside of each "leg" (prep those areas as well, just far enough that it doesn't touch the separate red areas).

 

[gorobei]

sugru might work but there isnt a ton of material to provide an attachment point, or else you just wrap it all the way around.

 

[balloonshark]

Would using a hot glue gun work? It dries stiff and should be fairly removable as long as you don't get too much down inside the hole. No idea of how well it would stick to your plastic though.

 

[ctbaars]

duct tape

 

[RPD]

I was going to say some type of epoxy putty but seems you've ruled that out. Have you lose the plastic part that broke off and gluing that back on is off the table?

Otherwise can you buy a replacement housing?