Troubleshooting when nothing seems to work
Alright. So we've done the ground clamp, we've done wire, we've done matching your settings to your metal, we've done the whole list. And I feel like this is the lesson people actually need most, because at some point, no matter how careful you've been, you're going to pull the trigger and get... nothing. Or worse than nothing. A pop and a spark and no weld at all. And you're going to stand there thinking you've somehow forgotten everything you learned.
You haven't. Something small is wrong. It's almost always something small.
I want to walk you through the order I check things in, because I didn't always have an order, and that cost me a lot of standing around confused.
Start with the ground clamp
First thing, every time, no exceptions. Check your ground clamp.
I've told this story to about a dozen people in this class already but I'll tell it here properly because it's the whole reason this lesson exists. I was welding one day, everything was fine, and then all of a sudden nothing. No arc, or a weak sputtery arc that wouldn't hold. I checked my gas. Fine. I checked my wire feed. Fine. I checked my settings against a chart I had taped to the wall. Fine. I was ten minutes into this, getting frustrated, starting to take the gun apart, when I looked down and the ground clamp had vibrated right off the table and was sitting on the floor.
Ten minutes. For a clamp that fell off.
So now it's the first thing I check, before I check anything else, and I'm telling you to make it the first thing you check too. Is the clamp actually attached to clean metal, actually making contact, actually still there. Takes five seconds to look. Save yourself the ten minutes.
Then work outward from the gun
If the ground's good, here's the order I go in:
Gas. Is the bottle open. Is there gas in the bottle. Did you leave the cylinder valve barely cracked last time and it's basically empty now. Listen for the hiss when you hold the trigger with the gun away from your face. No hiss, no shield, and your weld's going to look like a crumbly mess even if everything else is right.
Wire feed. Is wire actually coming out of the tip when you pull the trigger with the gun pointed away from you. Sometimes the wire's birdnested back in the machine, tangled up behind the drive rollers, and it's just not making it to the end at all. Sometimes the tension on the rollers is too loose and it's feeding but weak.
Contact tip. Is it the right size for your wire, is it clogged with spatter, is it burned back so the wire's not getting good contact. This one's easy to skip because it's a tiny part, but it matters a lot more than its size suggests.
Settings. Last thing I check, not first, because most people jump straight here and it's usually not the problem. Voltage and wire speed matched to your metal thickness, like we talked about a few lessons back.
I feel like that's the mistake most beginners make, honestly. They go straight to the settings dial because it's the most obvious knob to fiddle with, and they start cranking it up and down hoping to land on something that works, when the actual problem is the clamp on the floor or a clogged tip. Setup is where people lose the plot, not the welding part. If your ground's solid and your gas and wire and tip are all doing their job, the weld pretty much runs itself. Chasing the settings dial when something upstream is broken just wastes your afternoon.
A couple specific symptoms
Popping and no arc at all: almost always gas or ground. Check both before you touch anything else.
Arc starts but wire keeps sticking to the metal: feed speed's probably too slow for your voltage, or your tip's worn out.
Weird burning smell and the machine feels hot: stop. Let it rest. MIG welders have duty cycles, meaning they're not built to run forever without a break, especially the cheaper ones like mine. Running it too long can trip the thermal overload or, if you're really pushing it, damage something. If it smells hot, it's telling you something. Listen to it.
Everything looks right and it still won't strike: check your work cable and gun cable for damage. A pinched or cut cable can make everything upstream look perfect and still not deliver power. I don't run into this one much, cables are pretty tough, but it happens.
When you genuinely can't figure it out
Sometimes you'll go through the whole list and still be stuck. That's fine. Stop, don't force it, and don't just keep pulling the trigger hoping it fixes itself. I'm no pro, and there've been a couple of times I had to just walk away, come back the next day, and see it with fresh eyes. Usually I found it in about thirty seconds once I wasn't frustrated anymore.
Before next time
Next time you're at the table, deliberately unplug your ground clamp and try to strike an arc so you can see what "nothing's working" actually looks like. Weird thing to practice, I know, but it's a lot less scary to troubleshoot a problem you've already seen on purpose.