Shown is a set of RR pipes for a Bucks County LR, but w/ a shorter finial on the entry pipe it could be used for many styles of LRs. Early on I just didn't like a full length tab on the pipes and the resultant long slot in the web and seeing I only use one pin per pipe, even on the entry pipe, why have the tabs so long? The tabs shown are 1/2" long.
So after the pipe is formed, high temp silver solder is used to fill the groove in the ID and to close the tab. A reamer is then used to "clean out" the ID. The silver solder is 1/16 dia and 2 full lengths are req'd and it color matches the brass....which isn't important for the RR pipes, but I also use it on TGs. A Mapp Gas torch is used.
A size rod is inserted into the 2 piece entry pipe to ensure that both are aligned......Fred