Built out to obtain full throat thickness

[RARWOOD]

I have heard this term used in reference to the use of a 1/4" fillet weld, to weld a 1/4" plate to a thicker plate. The AISC specifications indicate the maximum size of a fillet along edges of material 1/4" in thickness or greater, is 1/16" less then the thickness of the material unless the weld is designated on the drawings to be built out to obtain full throat thickness.

How is this type of weld designated to be built out to the full throat thickness? All I have ever seen is the use of a standard 1/4" fillet weld symbol.

 

[eliebl]

From a pracical sense, a 1/4" fillet on the edge of 1/4" plate gives the chance of melting down the edge of the plate and not having an easy location to measure the fillet weld. I believe that is the reason for a reduced weld size. For a full throat thickness on this type of weld more care would be required to ensure that the throat if filled to a convex shape and not concave, then measured with a throat gauge not just a gauge for the leg of the weld.

The symbol would be such that you are specifying a fillet and adding a convex surface contour.

EJL