The wire is one MIG gun component that can make or break a successful weld. A good, steady wire feed increases your ability to maintain consistently good welds. But what if your MIG wire burns back to the tip, causing burnback? This common issue happens when the wire burns back inside your tip and forms a weld, sputtering your work to a quick halt.
Here are 5 ways to find the source of your contact tip burnback, fix it, and get back to your weld.
1. Wire-feed speed
Finding the right wire-feed speed for your gun can mean the difference between a smooth weld and one plagued with problems. In fact, a feed that’s too slow is one of the most common causes of burnback. Double-check your machine’s parameters, and up your feed speed if necessary.
2. Erratic wire feeding
There are a number of reasons your wire feed might be stop-and-go. If your parameters are correct, remove the nozzle and check your contact tip. The wire may have carved a groove in the tip – or maybe even welded right to the tip itself. The liner could also be a trouble spot. Look for buildup, a well-cut trim, and correct sizing.
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3. Improper tip stick-out / recess
A tip that’s too long (or too short) can also be a source of problems. Check the length of the tip vs. the nozzle. A good general rule to remember is the higher the current, the more the tip should be recessed. Use a longer wire stick-out to keep the tip away from the heat of the arc.
4. Improper electrode stick-out
Check the distance between your torch and your metal, and make sure you’re not too close. Keep a distance of at least a half-inch from the surface. Crowding your work is one of the most common causes of contact tip burnback, and one of the easiest to correct.
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5. Faulty ground
A less-than-perfect ground is another common cause of burnback. Even if you lose contact for just a few seconds, you’ll lose voltage but the wire will keep on feeding. Always attach your grounding clamps to your work instead of the table.