Glue for nylon?

My car key comes apart into the electronic section and the key section. The little tab that keeps them together is loose or broke or whatever and my key comes apart easily. Had a mini crisis this morning when I got to my car and realized the key part was missing.

I want to bond it together permanently. After researching the markings on it, the housing seems to be made of nylon, which to my understanding is extremely difficult to glue.

Pic 1
Pic 2

My plan is to fill the hole circled in Pic 2 with adhesive, which the thing circled in Pic 1 goes into, which should hold it together pretty well, but I don’t know what kind of glue I need.

Or would I get better results just melting it together with a soldering iron or something like that?

Of course the problem with bonding it together permanently is I’d have to take it apart to change the battery, but I’ll deal with that when I get there…

Yes, Nylon is impossible to glue with glues available to the homeowner.
The only thing that works reasonably well is hot-melt glue.

If you can “weld” the break with a soldering iron, that is likely to be the most secure bond. You could also drill a hole and use a screw…

Now that’s an interesting idea. Thanks!

…Huh. I’ve glued lots of 3d-printed things, and I’ve 3d-printed lots of things in nylon, but it’s only just occurred to me that I’ve never tried to glue anything printed in nylon.

Then again, I’ve also seen all sorts of information saying how difficult it is to color nylon, and I’ve had no difficulty at all with that.

Does the actual key fold out like the blade of a penknife?

I suggest you just run a few turns of some sticky tape (electrical tape, or a narrow strip of duct tape) lengthwise around the assembled key!

It does.

Considered taping it but then I couldn’t see the buttons (I know that’s a stupid excuse, but I frequently forgot which is which), plus I’m afraid of permanently “pushing” them with the tape. And it would be much bulkier with the key out all the time.

I cannot see your pictures for some reason, but you could try cleaning the surfaces with isopropyl alcohol to remove dirt and grease and gluing them with cyanoacrylate or epoxy adhesive. I don’t guarantee it will hold forever, but it’s worth a try.

You have a problem with adhesion, that is to say, nylon adheres poorly. I’d lightly abrade the bonding surfaces with 100 grit (or so) sandpaper to provide a physical tooth for the adhesive to grab, as it were. Epoxy (say a quick setting brand like J-B Weld) then to bond the two surfaces together. Don’t fill the hole: just use enough adhesive to form a film between the two halves to be bonded. A tight fit leaving a thin film of adhesive is more important than lots of adhesive. I’d use epoxy because one of the drawbacks to CA (cyanoacrylate or superglue) is that it can be a little brittle in uses where there is stress on the bond area and liable to crack and fail.

Isn’t a replacement for the plastic shell that holds the electronics fairly cheap (like under ten bucks)? It might be simplest to replace it.

I would think ordinary silicone adhesive/caulk would work fine, like GE Silicone II. It would be stretchy but would come apart later with a good pull.


Possibly. I do have an uncut, unprogrammed key I bought when I got the car, intending to get it cut and programmed as a backup (car only came with one key), but have repeated balked at the price to get it done at the dealer, and the locksmiths around me can’t do it (well, they could if they had the proper equipment, but none of them do).

Anyways, failing anything else I may give it a try, but what I really don’t want is to fuck it up and have no working keys.

I would get a non-electronic key cut and leave the original in the folded configuration - just use it as a separate lock/unlock keychain dongle. Fastening the case together without having to withstand the stress of fold/unfold/twist should be easier. Perhaps a black zip tie around the edge?

Why do you think it is nylon?
It looks a lot like polyethylene.
I would check the adhesive section at Home Depot. Each adhesive will have a list of bondage strengths for different materials.
I have glued polyethylene successfully but the glue can be a little pricier than epoxy and I would not be confident that it would be able to withstand the abuse your key might get but it is worth a try.

Because there is a marking on the inside reading “PA GF50” which, plugged into Google, leads to a full page of links to data sheets for a substance described as a “50% glass fibre reinforced polyamide blend,” i.e. nylon.

Maybe that’s just a coincidence, but I doubt it.

What about covering the whole assembly with electrical heat-shrink tubing?
Should be possible to connect the 2 pieces, but still have the key accessible for use. Maybe even just a strip of the tubing connecting them, but leaving the key slot open. then when it’s time to replace the battery, just remove the heat-shrink tubing, discard it, and install a new set.

If you can unlock/lock/run your car with a regular key, get one made and test it then put it in your billfold.
Then work on the repair/replace question.

Always have a back up key to everything someplace accessible.

If you have to have the electronics, get a replacement from the dealer and keep the old one as an additional back-up.