[Ronnie]

A cut and paste from Miller Welds.


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Which is better, solid wire or flux cored wire?
Neither wire is superior over the other. They simply have different properties, which work better on certain applications. As far as performance is concerned, both types of wire produce sound welds with good weld bead appearances when applied correctly and used within the proper parameter settings. Solid wire provides deep penetration in the root and usually has little spatter. Flux cored wire has a larger ball type transfer and produces low spatter levels. In addition, flux cored wire produces a rounder penetration profile with excellent sidewall fusion.
As far as user appeal, both solid wire and flux cored wire are relatively easy to use and are ideal for novice and occasional welders working in automotive, farming and home hobby applications. Operator appeal on solid wire may be better on thinner applications because there is no slag to remove; it is ready to paint; and the weld beads may be more aesthetically pleasing.