I first saw this stuff years ago, when Repco had a plastic loop glued to a display with the stuff, and no-one could pull the loop off the display, and plenty had tried.
It's called "Q-Bond" and it's a black and grey powder (use black to repair dark things, and grey to repair light things) and a liquid that sets the powder just about as hard as steel in 10 seconds.
I didn't buy it at the time because it's expensive stuff at $33.00 a box, but I recently put some mounts onto my roof rack, that are quite commonly stolen, so I put threadlocker on them as I put them on, and then put a small pile of the powder over the head of the bolt, and then set it with the liquid. No-one is unbolting these mounts from my roofrack now. Not without an angle grinder.
I have to say I'm amazed at the stuff. I repaired my daughter's favourite earring, and then one of her favourite rings, and then the cracked pipe on the vacuum cleaner, and now I'm finding myself looking around the house wondering what else I can fix with the stuff.
It's apparently able to even fix a cracked head on a vehicle, but I'd imagine you'd be wanting that to be a pretty temporary repair.
You can also bridge a repair from one point to another by running the powder along some tape, and then setting it, if the instuctions are to be believed.
I go 4wding a lot for my photography, and get well off the beaten track, and I'll be keeping this stuff in my toolbox now for sure. If it's as strong as they say, and can repair the kinds of things they say it can, then it ought to be an awesome addition to my toolbox.
I mention it here, because I imagine it would be useable to repair some photography stuff too, should you damage a tripod, or have a strap give way on a camera bag, or even just to do useful things like I've just done, and attached a loop of shock cord to my lens cap, so that my lens cap is now always attached to the lens (no more wondering which pocket I put it in, or where else it has ended up), and black on black you can barely tell.
I have to say that I am not in any way associated with the product or the company, just sharing the info here for those who travel off road, or may need to effect a repair on the spot while out taking photos etc. Hopefully I haven't trod on any toes in doing so, I'm just pretty impressed by the usefulness of the stuff.