Should the weldolet fit-up be stub-in or stub-on?

The fit-up of a weldolet should generally be stub-on, as this configuration provides a more secure and stable connection by allowing the weldolet to be directly welded onto the pipe. This approach minimizes stress concentration and enhances the integrity of the joint. Stub-in fit-ups can be used in specific applications, but they may complicate the welding process and potentially introduce weak points. Ultimately, the choice may depend on factors such as pipe size, application, and design specifications.