Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Thanks @Stoker understood on all points.  The front of the boiler is a "cap" and the solder sweat seam has slightly failed.  So not a rip/hole/gap.  Seems on the internet's fellows recommend Zap-a-gap, a few others Gorilla Glue.  Going to give my Gorilla Glue a try.

I cleaned the area with with alcohol and then acetone.  Then did a ample bead of Gorilla Glue using a toothpick to agitate the glue around on the seam.