[xenomachina]

JB Weld is an epoxy. It starts out as a (2-part) liquid, and sets to a hard solid. It's good for fixing cracks or breaks in rigid objects. You want to avoid getting it on your skin.

Sugru is a putty. It's squishy, kind of like clay, and air-cures to a sort of rubbery flexible solid. It's good for repairs to things that are flexible (It's great for repairing and ending stain relief to cables) and also for adding "bumpers" to things or even molding small objects (like hooks). It's also safe to touch uncured Sugru with your bare hands. This makes it a lot easier to work with, in general.

The big downside to Sugru is that it's expensive, it goes bad after a few months (but storing it in the fridge extends the lifetime to a couple of years), and once you open a packet, the whole packet will cure within 24 hours. You pretty much always end up with some waste. If they could somehow make it 2-part so you could make the exact amount you need, or store it in a tube or something so it wouldn't go bad so easily, it would be great.

[markkanof]

There are a bunch of different products under the JB Weld brand that are two part clay like material. They are designed for things like patching wood, patching metal, etc. The two parts are different colors, so you take the two parts, squish them together, and knead them a bit until they have a uniform color and then you can mold them into whatever shape you need. I've used the wood one quite a bit for repairing small rotted sections of wood and it works well. Not sure what the shelf life is, but in it's two part state I've had containers around for over a year and they seem like new.

[xenomachina]

I've used two part putties that should like what you're describing, though I think the ones I'd used weren't JB Weld brand. I'm pretty sure they were all epoxies as well.

When the JB Weld putties you're talking about cure are they hard and brittle, or flexible and squishy? The ones I'd used all cured to a hard plastic.

[atombender]

JB Weld comes as a putty: https://www.amazon.com/J-B-Weld-8277-WaterWeld-Epoxy/dp/B000....

[xenomachina]

Yes, I fell into the trap of assuming a brand name actually has a fixed meaning.

Still, that's an epoxy, and if it's like the epoxy putties I've used, I bet it cures to a hard and rigid plastic, rather than the soft and flexible rubber that "Sugru brand mouldable glue" cures into.

[namibj]

I doubt the underlying chemistry is unable to produce elastomeric products. Especially if you look at e.g. 2 part Polyurethanes, you see that while they aren't healthy in their uncured state, they are not fundamentally unable to be made into a non-liquid form, as they don't fundamentally rely on being a liquid.