We will create the upper weld as Part 3 and use the Mirror command to create the lower weld. The lines of the lower weld will then be modified to place them in Part 4.
Draw
Line. Type 3 in the Part: field.
Pattern
Mirror.
Modify
Attributes.
Clipboard
Delete. Since this line does not belong to any of the part outlines, it must be removed before the 2D mesh can be generated. Note that you can also press the Delete key, rather than using the ribbon command. The model should display as shown in the following image.