The SolidWorks help section says that the weld "this side" is above the line on a weld symbol and the "other side" is below the line.
I have always been taught, (and I have confirmed with several sources) that the arrow side goes below the line and the other side goes above the line.
Design & Drafting Engineer
Fresenius Medical Care North America
475 W. 13th Street
Ogden, UT 84404
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