I don't know the context in which you have seen these terms, but:

A butt weld is a weld joining two pieces of material that are aligned by their edges.

All weld is a term we use in electrode manufacturing to indicate that the chemistry reported on a certificate is taken from an undiluted weld pad.  That means that the bead-on-plate deposit needs to be at least 6 layers high or 3/4" high minimum to ensure that there is no base metal in the surface to be analyzed.

There is also the term "all weld metal tensile" which means a tensile test specimen is machined from the center of a groove weld so that the area to be tested (the center of the sample) is taken from the centerline of the groove.

Check this page out to give you a piture of what a butt joint or butt weld looks like. http://www.tpub.com/content/construction/14250/css/14250_51.htm

As for the All weld I've never heard that slang before.  Maybe your thinking of the weld all the way around symbol.  Or maybe your thinking of a full penetration v-grooved butt joint.