Mighty Putty is a two-part epoxy that can be applied to "most any surface." It can "support up to 350 pounds," says the late pitchman Billy Mays, still appearing at www.mightyputty.com, and (cue truck towed by a puttied chain) "pull this fully loaded, 80,000-pound tractor-trailer!" You cut it like dough, knead it, apply it, and let it dry.
We used Mighty Putty to join overlapped pieces of plastic, metal, and wood; clamped them; let them cure for 24 hours; then measured the force needed to pull them apart. We didn't tow a truck.
It's moderately mighty but pretty pricey ($19.99 for six sticks). It took more than 350 pounds of force to break its hold on metal and wood (270 pounds on plastic) and it excelled at filling gaps. But other adhesives are stronger and cost less.