Originally Posted by commander_taco
I still have one unaswered question: How come lugs are stronger? How can a bond between steel and bronze be stronger than the bond between steel and steel? It just does not work that way owing to the metallurgical differences (also note that steel and bronze do not react). For the record, solder is weaker than a weld. Lugs may be strong enough for bicycle application (altough anything is debatable in the absence of hard data), but I like to hear an explanation as to *why* lugs are stronger than welds. It is easy to make an assertion without proof...I guess you see my point.
thanx.
Heating steel enough to weld it weakens the metal. A welded joint will normally fail right at the edge of the weld where the metal has been heated by the welding process yet there is no reinforcing fillet.
The whole point of brazed lugged joints is that it's necessary to heat the metal less. Silver is better than brass because it melts at a lower temperature so less heating of the parent tubeing is required.