Super glue is a cyanoacrylate glue that gives off methyl isocyanate when it cures - that's what killed all those people in Bopal, India back in the 1980s. I would be wary about sucking it into your mouth or lungs as it is a carcinogen. Don't get upset if you've glued it already but I'd let it cure for a couple weeks before I use it. For my pipe stems I use a soldering iron at a low temp. If you use a high temp it has a tendency to bubble the material. Use a low temp. and drag down across the crack without displacing the stem material too much. Then sand the rough surface (I use a fine fingernail file). Then use fine sandpaper or steel wool and then polish (either use very fine sandpaper or use a buffing wheel with brown tripoli then white diamond and someone suggested jeweler's rouge for the final polish. Some people do this using t-shirt material impregnated with the polishing compound. If this sounds complicated just rub the stem with increasingly finer grit polishing compound. I hope this adds something to your information library.