I am just starting out welding. The job is to fillet weld 2"x1" 16 gauge (1.2mm) Rectangular Mild Steel Tubing for fabricating a frame. I have a 250 Amp DC welding machine. Can you suggest Electrode diameter and current? I currently have 8mm electrodes. Would they work fine if I used a low enough amperage setting?

  • What welding process? Commented Jun 13, 2020 at 17:16

2 Answers 2


In my humble opinion, 8mm rods are way to big for 16 gauge mild steel. You'd need about 250 Amp for that size rod and you'd melt your stock. I wouldn't use a rod any bigger than 1/8". You'd need 50 to 90 Amps for that size rod. A 6013 welding rod should work fine and it's good for ac and dc welders.

Since you're a beginning welder, practice on a few pieces of scrap stock just to get the feel of a smaller rod.

  • Heck, 1/16" rods are commonly available. Or perhaps the OP would be looking for 1.5mm rods as the metric equivalent. Swatting a fly with a sledgehammer....
    – Ecnerwal
    Commented Jun 13, 2020 at 14:15
  • So, ideally, should I be using a 1/16" rod? Also, can you guys recommend a reference/table which mentions the recommended electrode sizes for various typical stock sizes. Commented Jun 13, 2020 at 15:48
  • @afterburner77 I can't really recommend a reference table but there are many of them available on the net or where you get your rods from. A 1/16" would be fine too. A lot of this depends on individual technique. I once did a job on an overhead crane and started out with 1/4" rods and finished it with 1/8" ... just took a slower pace.
    – JACK
    Commented Jun 13, 2020 at 16:20

I suggest going to MIG, much easier for a new welder ( or a crappy old welder ). Your thin stock would be a challenge for an experienced welder with stick ( SMA ) and any size electrodes and reverse polarity.

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