Hi fst951,
Blunt meaning obtuse or less pointed at the end of the electrode. A pointed electrode is generally used with DC current, and a rounded electrode is generally used with AC. With conventional AC current, better arc action is obtained when the electrode has a hemispherical shaped tip. For your application, the taper length should be about two times the electrode diameter, and the tip should be shaped to about .75 times the electrode diameter. Grinding the electrode to a point helps starting the arc when making short duration welds. A flat spot or tip diameter at the end of electrode works best and reduces erosion at the thin part of a point and reduces the concern that the tip may fall into the weld.