I started my mobile cart for my bender this morning. I'm using 1.5" .120 square tubing for the framework. I made the move up from .025 to .030 wire on the welder. Set the welder to recommended power and wire speed settings and went to town. First weld turned out like a charm. Then I started running into trouble. I started blowing through the tubing on the ends. First time, turn the power down a little, second time, a little more adjustment to the power, still had some problems. Thinking back, my first weld, I had the gun at an angle. The rest of the time, especially one the blow-throughs, I had the gun straight on with the tubing. Is this my problem? Thanks.

if your stand off is too short you'll burn through. Could be that. You moving at the same speed? Is the fitment the same on both tubings?

Are you moving to slow? Are your joints fit up tight?
other than that practice- I'd say.
Also one should note - It is impossible to make every welding machine exactly the same-meaning that if you had two of the same machines together both set at the same WFS(wire feed speed), and Voltage that one could be much hotter than the other & vise versa.
This is why the settings chart on machines say "RECOMMENDED AS A STARTING POINT" you the operator MUST be able to recognize to cold & Hot , to high volts, to fast o wire etc. Even though you have the settings set at what they say it porbably isn't right. Generally from my experience the settings are usally HOT. (manufacturers liability?) dont know.
weldpro

just read the other reply- mikes' correct your ELS Electrode Stickout it is the distance from end of wire to contact tip. If its short in can increase voltage , and if its long decrease it. However the change isn't massive ( if your in the 1/4 to 1/2 els) that why wire feed welders are CV constant voltage.

You hit the nail on the head when you mentioned angle. There are two angles to worry about, lead angle (angle that you are pushing the wire into the puddle in direction of weld), and work angle (perpendicular to direction of weld) Sounds like you need to change your work angle towards the tube that is recieving heat on the corner. Think about how you are applying heat to the tube, on one piece you are heating a corner, so heat has room to conduct throughout two sides of the square. The other piece of the weldement is recieving heat at the end, and can only transfer heat to one side. If the work angle is focused more to the piece being heated at the end, you'll end up blowing through. Change the work angle to focus more on the corner of the piece, and let the puddle flow towards the piece end butted to it and you should be fine. Make sense?? dont know how clearly I've explained this. It sure is alot easier to show someone how to do something than to try to explain it with the written word. Hope it helps.

:flipoff2:

Thanks guys. My fitment was great, but when I got to the last end to be welded, the tube was not in contact with the end of the tube I was joining it to, so I pushed it down and then got it together. Hopefully I should get around to the other end of the frame tomorrow and use what y'all told me.