Application
AC aluminium TIG: choosing the electrode that holds its ball
Aluminium on AC is where electrode choice is most visible: the tip must ball, stay balled, and not spit tungsten into a weld that will be inspected. Two types do this job — and the thickness you run decides which.
| Section / duty | First choice | Why |
|---|---|---|
| Sheet up to ~3 mm, light duty | WP green | Balls easily, lowest cost, universally available |
| 3–10 mm, production duty | WZ8 white | Stable ball at higher AC current, less spitting |
| Thick plate / castings, long arcs | WZ8 white one size up | Zirconia keeps geometry under heat load |
| AC on inverter with square wave | WP or WZ8 per section | Modern AC is gentler on tips; follow section, not machine age |
Bench notes
Let it ball, don’t force it
Chamfer lightly and form the ball on a scrap block at working current. A pre-balled tip starts cleaner than a ground point on AC.
Watch the ball size
Ball grows with current and time. Over-balling drops tungsten into the puddle — the classic radiograph reject. WZ8 delays that failure mode noticeably.
Diameter tracks amperage
Use the size tables: thin sheet 1.6–2.4 mm rods, plate 3.2–4.8 mm. Under-sized rods over-ball; over-sized rods wander.
Stock both colours
Shops that run mixed aluminium work keep WP and WZ8 side by side; mixed cartons from 100 pcs make that a single order line.
Welding steel the other half of the week? The DC side lives on the lanthanated page.
Send your electrode list today
Type, diameter × length, quantity and packing — mixed sizes welcome. You get a specification-confirmed quotation with lead time, normally within 24 hours.