Welding Issue

[49erRider]

Well hopefully this qualifies. Anyways somewhat new to welding but I'm using a Lincoln Pro Mig 180 with 75/25 Mix. Anyways I'm having some issues every once in a while. About 50% of the time I can throw down a really nice bead that penetrates well.

Then the other half of the time I can't get the bead started. It more or less just "flames" then burns up the wire towards the tip.

I can take a video if that helps. Any suggestions?

 

[2stix]

sounds like the heat setting is too high, or wire speed too low. this happens all the time when trying to overhead weld. the arc starts but the wire isnt making it to the metal fast enough, then burns back into the tip. you will see balls forming in the tip cup, then falling onto you. you need to also check your wire roller tension. if it is too soft it can slow the wire speed, especially when there is a sharp, or multiple bends in your cable. keeping the cable as straight as possible helps. also check that your tip is large enough for the wire you are useing. when the tip gets hot it can expand slightly and make the wire drag a bit as it passes through, esentually slowing the wire speed as it sticks and releases. if this is a new machine, you probably need to adjust the roller tension. if it is an older machine, the roller may need cleaning in the groove. also check which groove you are useing. they normally have a small and a wide groove, depending on wire size used.

 

[49erRider]

Ahh I've adjusted the wire tension but I didn't know to soft would slow it down. I'll try to tighten it a bit and see if that helps.

 

[2stix]

especially if you are twisting and bending the cable around. the more it bends, the more the wire is slowed down. and dont forget to check the tip. if you have been burning up into the cup, the tip may have some slag stuck to it and slowing the wire too. i have had to buy a set of tips at the local HF on a weekend, and found that the tips were drilled just a bit small, or a bad drill, but they drug the wire when the tip got hot. luckily i have tip cleaners and borers so i was good to go. but it is frustrating as hell when it happens.

 

[Seiler]

In relation to 2stix's posts (great information by the way :thumbup, how new are all the consumables? I had a similar issue with an old machine in class my first semester. I can't think of the dang brand right now for the life of me, but the contact tip was all rounded out and worn out. Slapped a new one on and it worked great.

Also, two "doh" circumstances that I can also think of is making sure your ground clamp is securely attached. If you're trying to complete the circuit through paint, or a dirty surface --- it can have a severe affect. In addition, pay close attention to the duty cycle. If you're pushing the machine over its rated limit, it can damage it badly and cause it to act unusual.

If none of this helps, I'd start messing with the settings too. Sounds like you might have your voltage too high.

S