Contact Tip and Wire Size Matching Chart

What it is

The contact tip transfers welding current to the wire and guides it to the joint. Its bore must match the wire diameter: too tight and the wire jams or burns back; too loose and the arc wanders and current pickup becomes erratic. Tips are stamped with the wire size they are made for, in inches, millimeters or both. Tips are also specific to a gun maker's thread and length, so size alone is not enough to order.

How to identify

1. Read the stamp on the tip body, often on a flat or the side. Common marks: "035", ".035", "0.9", "0.9mm".
2. Read the gun's series or the old tip's part number for thread and length.
3. For aluminum, look for a tip marked for aluminum (often with an "A" or a note) or a size marked one step larger.
4. If the stamp is worn off, check the bore with a wire of known size. Do not drill out tips.

Wire size and tip marking

Inch and metric sizes are close but not identical. Match the tip to the wire actually loaded.

Key points

• Aluminum expands with heat and is soft. Tips made for aluminum or one size larger reduce burnback.
• Some flux-cored wires need a tip sized for the wire's actual diameter tolerance. Follow the wire maker.
• Tip, diffuser and nozzle are a matched set within a gun series. See the MIG consumables sheet.
• Heavy-duty tips last longer at high amperage and in spray or pulse transfer.
• Replace tips when the bore is worn oval, spatter builds up, or the arc starts wandering.

Common mistakes

• Running .030 wire in a .035 tip "because it fits".
• Reaming a tip to fix burnback.
• Using a steel tip size for aluminum.
• Assuming 0.8 mm and .030 tips from different makers interchange.

Governing standards: No single governing standard. Follow the gun maker's and wire maker's data.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.