I assembled the slip joints with some Permatex copper/silicone that BruceM and others suggested.
Cleaned the surfaces with Acetone, put a bead on the inner surface, 2 beads an inch apart on the outer surface - boy, it's thick stuff, needed some squeezing out of the tube even with a 5mm hole in the nozzle. Then the joints were slipped together.
Left it overnight, started engine.
It's nice to breathe fresh air in the shed.