Looking closely at your pics...it may be a case of this solder infill is whats stopping it coming apart,..for its my way of thinking that whoever did this heated the solder in a melting pot,then poured it into the gap,..but how much was poured in..that,s the big question....but, as i,ve said in my previous post...getting it out is,nt too hard...Using a soldering iron..may be ok for what you can see, but if as i suspect..its all the way down that tube,then the oven is your best bet....