AC tig and stick....enlightenment!

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I have tried to AC tig off my TB302 without a high frequency box and the arc just doesnt work.I understand that its because when the current goes from one direction to the other (hertz). Then right in the middle there it is at "0" so the arc goes out.Assuming that my understanding is correct the how com when im stick welding, on the same machine on AC the rod burns consistantly?its been torchering me for ages.G
Reply:All materials and substances have what is called a "breakdown voltage" this is the voltage that when exceeded will cause and insulator (non conductive material) to break down, ionize and conduct current (form an arc). Once the material has begun conducting it usually requires much less voltage to keep conducting (maintain the arc).Normally, air is an electrical insulator but when enough voltage build up between the ground and clouds the air will break down break down, ionize and conduct electricity until the voltage has been discharged, we call this lightning.In GTAW (TIG welding) the arc gap through the argon atmosphere created by the shielding gas has a breakdown voltage of several thousand volts. The purpose of high-frequency is to create a very large voltage between the torch and work to exceed the breakdown voltage of the argon making it conductive and allowing the welding current to flow. The welding voltage alone is not enough to reignite the arc each time it is extinguished when welding with AC.SMAW (stick) electrodes that run on AC have chemical stabilizers in their flux coating that burn in the arc to make the shielding atmosphere have an extremely low breakdown voltage, a voltage that is less than the welding voltage. This means that the arc can be easily reignited each time the amperage/voltage of the welding machine passes through 0 without the need for any sort of high frequency assistance.The actual chemical that produces a stabilized AC arc varies depending on electrode type.For example the difference between an E6010 (a DC only rod) and an E6011 (the AC capable equivalent to a E6010) is that the sodium in the E6010 coating is replaced with potassium in the E6011 to allow for arc stability when running AC. They are both cellulose based rods and I can't tell the slightest bit of difference when running the both on DCEP.Visit Tensaiteki.com
Reply:Originally Posted by TensaitekiFor example the difference between an E6010 (a DC only rod) and an E6011 (the AC capable equivalent to a E6010) is that the sodium in the E6010 coating is replaced with potassium in the E6011 to allow for arc stability when running AC. They are both cellulose based rods and I can't tell the slightest bit of difference when running the both on DCEP.
Reply:thanks Tensaiteki.didnt realist it was so complicated, but nice job explaining.migth have crossed my "need to know" limit, but leas i can sleep easy now knowingG