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Issues with "round" weld beads

Posted: Wed Jun 06, 2012 3:19 am
by dubcanuck1
Hi all,

I've been practicing MIG welding and I noticed that, in particular, when welding inside corner joints, the weld bead tends to be round with a lot of undercut. On butt welds this is less so. I turned up the amperage and fiddled with the wire speed and the butt welds seem to be coming out a lot flatter and looking good. However, the inside corner welds are still kicking my arse.

I've been welding forehand (oops. leftover from OAW) and after checking the "stickout" articles, I notice that my contact is recessed about 38". I'm going to cut down the the tip so that the stickout is flush. Any other tips for welding inside corner welds? I'm doing 90 degree welds of thin tubing to a thicker flange. The one that's really killing me is a flange with a transition tube that goes from 1.5" at the flange to 2.5". This makes the space for the torch pretty tight and with only about 70 degrees to work with and so the weld never "sits in there". It always grabs either the flange or the tube and looks like the "dogs turd" that everyone talks about....

I'm wondering if I should cut a nozzle so that the contact tip is actually protruding.

Help a fella out?

thanks.

Re: Issues with "round" weld beads

Posted: Wed Jun 06, 2012 12:13 pm
by Ultralow787
I'm thinking you are on the right track with your ESO. The contact tip should be flush with the end of the nozzle for short circuit MIG. If you are already recessed 3/8" plus add the limiting effect of trying to get into a corner, and the total contact tip to work distance could be easily 3/4".
This would make the wire stick out further, increase resistance, and make the weld deposit colder.
I would think that when you are doing a flat butt joint, you are getting the contact tip much closer to the weld.

That's about all I can offer, but the others will be along soon and they may have more info for you.
Oh, one more thing, on the inside corners, can you drag the weld vertically down? This would be "backhand" with the torch pointing upwards.

Jody did some videos on forehand, backhand, and straight in. The backhand is supposed to get better penetration because the heat energy is focused on the weld deposit as long as you keep the wire on the leading edge of the puddle. In Jody's opinion, he found that it made very little difference and that the work will determine gun position in more cases than not.

Welcome to the forum by the way!!

Re: Issues with "round" weld beads

Posted: Wed Jun 06, 2012 3:53 pm
by dubcanuck1
Yeah. Jody's videos kick ass. I had watched a bunch and read as much as possible and figure I should doublecbeck to make sure that I was interpreting everything properly.

Now I have to grind off a bunch of dog turd on a bunch of stuff. Yay me....

Re: Issues with "round" weld beads

Posted: Wed Jun 06, 2012 10:20 pm
by dubcanuck1
Oh my god. It's night and day. I spent 30 minutes cutting out the crappy old dog coils and shaved down the tip. The new welds went in nice and flat and are nice and shiny. Thanks Jody for the vids and thanks for the help guys! Now to keep practicing..and to spend another hour cutting and grinding my flange apart.