Suppose your client wants to label the shop welds consecutively. Suppose the shop welds on the first spool are numbered 1 through 4 and you want the welds on the second spool to be numbered 5 through 13.
Display the second spool drawing and press Ctrl+T to show the weld window. Enter the label 5 for the first shop weld. With the focus still on the first weld, press Alt+R or the Repeat button several times until all the shop welds are labeled.
Remember to resave the drawing.
You can also use a batch process to label welds consecutively across many drawings or even a whole job. Before you start, create a list of the drawings you want to process. Make sure that the list is correct. Then set the label of the first shop weld on the first drawing in the list, then resave the drawing. Select File, Batch Operation. Make the selections shown below, then click Proceed… to run the batch. Starting with SpoolFab 8-797, this process includes tack welds.