I've used the MT-13 resin epoxy to glue on metal takedown sleeves for Cherokee style archery bows and it is a great, water proof glue. Very, very strong.What I call Smooth-On is thier standard PC-3 epoxy. You can use it as is and let it cure under clamping pressure for 24 hours which is what I've done, but a lot of guys use them for gluing fiberglass laminates under heat and pressure (cures quicker) when making fiberglass recurve bows. It will leave a black-brown line. This is an epoxy you can probably get locally if you live in a good size city.
They are both great glues.