Sounds like a stitch weld with a fillet symbol. If this is the configuration, then you can use the fillet symbol with the details to the left of the symbol and even make a note delineating the lengths. I will email you a sample. Tell me if it is the design you described.
By -
Date 10-20-2000 15:11
guess you got to draw it out there is no way to apply a weld symbol for round stock in your situation.
Is there a specific reason you don't want the tube welded all around? If not then it may be simpler just to do so and not worry about exactly where the welds are placed. The weld would only be about 2 inches longer which could be welded in less time than it takes to layout the starts and stops. And there would be fewer potential defects.
Otherwise, as was already mentioned, you may have to provide a detail showing exactly where you want the welds located. That would supercede any welding symbols.
C H Guilford