Question: What is the best practice, a Scallop bar or direct pin system?
Answer: When designed properly, both systems can survive for decades. However, the Scallop bar system utilizes a 304SS stud welded directly to a 409SS scallop bar. This dissimilar metal has different thermal coefficients. Over time, these areas will crack, and the connection will fail. The Liner pin is also a dissimilar metal weld, but is located at the casing plate, therefore the temperature and the thermal coefficient is Minute.