Since neither of the emaIls had links or pic attached,  looked that up on the font of all things Amazoned, there are a few options including JB Weld high temp super glue. The stuff in the caulking gun tube or squeezable tube may just be high temp silicone which I have used but don't think would sustain pulling or twisting of a plate/grid cap.  The real issues is that the stuff that looks like it is real furnace cement comes in high dollar plastic tubs, enough to fix a million tubes with.

Charlie, W4MEC