.. I would never rejoin a loose rib that was originally soldered with any type adhesive, but the fact remains that adhesives are used at NASA to hold the heat shielding tiles on the space shuttles, and the temps on the skin reach 2300 degrees. Ya' think double barrels get that hot?
SRH
I don't think many of them needed to for a problem to develop. I've witnessed the ribs coming loose, as in being shot off, on 20ga. FN Superposed guns twice in
'hot corners' in SA when it was no hassle to take your own guns down to shoot. Those ribs were soft soldered; neither were mine. I've shot or had the rib come loose on a 101 Winchester trap gun; it didn't fall off, but became detached for some inches forward of the receiver and ended up requiring relaying both side ribs as well to doit correctly on the repairs. Actually may have cost me more than the gun was worth [pretty sure it did, but you know how hard it is to face THAT reality], but it was one of the first 101's and had that small grip like an old FN 20 Superposed that just had a certain 'feel' I'd become fond of & the loose rib bugged me. I still enjoy shooting it and the work was done correctly. Had I some 'glue' like you ref., I would have gladly used it:-)
Presently have a nice French 16 SxS w/a lower loose rib issue, not wholly detached, but needs remedy. Lug is fine, not affected in the least which is surprising & gun remains on face & tight as a tick. Affecting a repair to the lower rib may end up exactly as SKB said. I dunno, yet. Its a bucket list item.
Solder joints are not all equal, material difs., flux, who's doin' it, solder itself.. they all play in the equation. And as far as I know all of them irrespective of any of the aforementioned will fail well before 2300°F.
Short answer to your question: Nope, but they don't need to before the threshold of failure is reached for soldered ribs.
