7018 is a DC "reverse polarity" rod that doesn't like to run well on an AC buzz box. When the only thing I've got available is an AC welder, a switch to 7014 gives a bead that's almost identical to the one 7018 produces on DC, and it runs a LOT easier, and at lower amperage.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!