← Back to Bead BoardWelding wire & gas selection guide
This welding wire selection guide and shielding gas chart covers every common process. Pick the right wire type, wire size, and gas for MIG, TIG, stick, and flux-core by base metal, with AWS filler metal specs.
Quick answer
Mild steel MIG: ER70S-6 wire with 75/25 Ar/CO₂ (C25) gas. The most common setup in fabrication shops.
MIG wire by base metal
MIG wire size guide
TIG filler rod by base metal
TIG rod diameter by thickness
Stick electrodes
Stainless steel stick electrodes
FCAW wire selection
MIG shielding gas matrix
TIG shielding gas matrix
How to read AWS filler metal numbers
Every filler metal classification tells you what it is if you know how to read it.
E7018: E = electrode. 70 = 70,000 psi minimum tensile strength. 1 = all-position (1 = all, 2 = flat and horizontal only). 8 = low-hydrogen iron powder coating, DC+ or AC.
ER70S-6: E = electrode, R = rod (can be used as either). 70 = 70 ksi tensile. S = solid wire. 6 = chemical composition (higher Si/Mn deoxidizers).
E71T-1C:E = electrode. 7 = 70 ksi tensile. 1 = all-position. T = tubular (flux-cored). 1 = usability and performance type. C = CO₂ shielding gas required (M = mixed gas).
Questions welders keep asking
What is the difference between ER70S-6 and ER70S-3?
ER70S-6 has higher silicon and manganese content, which makes it more forgiving on mill scale, light rust, and dirty steel. ER70S-3 has lower deoxidizers and produces a cleaner arc with less spatter, but the base metal needs to be clean. If you are welding new material that has been ground or wiped down, ER70S-3 gives you a nicer bead. If the steel is as-received with mill scale still on it, use ER70S-6. Most fab shops stock ER70S-6 exclusively because they do not want to deal with the distinction.
Should I use ER4043 or ER5356 for aluminum?
It depends on the base alloy. For 6061 and other 6xxx series, use ER4043. It has higher silicon, flows better, and resists hot cracking on 6xxx. For 5052, 5083, and other 5xxx marine alloys, use ER5356. It has higher magnesium, gives a stronger weld, and color-matches better after anodizing. Do not use ER5356 on 6061 for anodized work if appearance matters less than crack resistance, and do not use ER4043 on 5xxx alloys because you lose strength. When in doubt on a mixed joint, ER4043 is the safer general choice.
What shielding gas do I need for stainless steel MIG welding?
For spray transfer on stainless, use 98% argon / 2% oxygen. For short-circuit transfer (thinner material, all positions), use tri-mix: 90% helium / 7.5% argon / 2.5% CO₂. The tri-mix overcomes the sluggish stainless weld pool and keeps CO₂ low enough to avoid carbon pickup. Some shops use 98% argon / 2% CO₂ as a simpler alternative to tri-mix for short-circuit, and it works fine for non-critical work. Never use straight CO₂ or C25 on stainless, as the carbon contaminates the weld and ruins corrosion resistance.
Do I need tri-mix gas for stainless MIG?
Only for short-circuit transfer. Tri-mix (90 He / 7.5 Ar / 2.5 CO₂) is designed to add heat to the sluggish stainless puddle in short-circuit mode. If you are running spray transfer on thicker stainless, 98/2 Ar/O₂ is the standard and works great. Tri-mix is more expensive, so if you can run spray, skip it. But for thin gauge stainless or out-of-position work where you need short-circuit, tri-mix makes a real difference in bead appearance and puddle control.
What is the difference between self-shielded and gas-shielded flux-core wire?
Self-shielded flux-core (like E71T-11) generates its own shielding gas from the flux. No bottle required. It works outdoors in wind where gas-shielded processes lose coverage. Gas-shielded flux-core (like E71T-1C) uses external CO₂ or C25, gives cleaner welds with less slag and less spatter, and has higher deposition rates. Use self-shielded for field work, outdoor structural, and windy conditions. Use gas-shielded for shop fabrication where you have gas available and want cleaner, faster welds.
Which stick rod should I use on rusty steel?
E6010 or E6011. Both have cellulose coatings that produce a forceful, digging arc that burns through rust, paint, and mill scale. E6010 is DC+ only, so you need an inverter or DC generator. E6011 runs on AC too, so it works on older transformer machines. For structural or code work on clean steel, E7018 is the better rod (low hydrogen, higher tensile), but it does not tolerate dirty surfaces. If the steel is rusty and you cannot grind it, grab the 6011.
Can I MIG weld aluminum without a spool gun?
You can, but it is a pain. Aluminum wire is soft and tends to bird-nest in a standard MIG liner. You need a Teflon liner, U-groove drive rolls (not V-groove), very light drive roll tension, and the shortest torch lead you can get away with. Even then, 4043 wire in 0.035" feeds better than 5356 because it is stiffer. A spool gun puts the spool right at the torch, eliminating the feed path issue entirely. If you weld aluminum more than occasionally, the spool gun pays for itself in frustration saved.
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Welding Cost Calculator
Cost per inch of weld — labor, filler, gas, and markup by process.
Metal Weight Calculator
Plate, pipe, bar, tube. Steel, aluminum, stainless, brass.
Gas Usage Calculator
Cylinder count and cost for a project. MIG, TIG, flux-core.
Filler Metal Calculator
Pounds of wire or rod for a joint. Spool count and cost.
Job Pricing Calculator
Build a bid from scratch — tasks, materials, overhead, margin.
Welding Settings Chart
Amps, voltage, wire speed by process, metal, and thickness.
Welding Symbol Chart
Every AWS A2.4 weld symbol. Searchable with visual diagrams.