Ceriated tungsten electrode

Cerium oxide in tungsten makes the arc more stable and easier to start. The electrode stays cooler and the tip holds its shape longer. If you treat the electrode wrong, like with too much current or on the positive pole, the tip melts off. Then tungsten gets into the weld pool and makes hard, brittle spots in the weld. For AC on aluminum, these ceriated ones are not so good; better use zirconium or lanthanum. Always grind the tip lengthwise to the electrode and keep it clean. Run it on DCEN, then it lasts longest. If the tip starts to drip or the arc is fussy, it's done – then replace it.