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MIG Heat and techniques.

Posted: Thu Apr 14, 2016 5:35 pm
by Sethmark
I've been doing a bunch of destructive testing lately and have been investigating heat, technique and aesthetics.

This is single pass .035 wire, 75/25 and roughly 23v and 380 wire speed on .250 wall CRS. Same pattern with a tighter weave left vs right. I'd like to solicit thoughts from the peanut gallery. I don't have any toes so don't worry about stepping on them.

Re: MIG Heat and techniques.

Posted: Thu Apr 14, 2016 7:58 pm
by Otto Nobedder
That look pretty good, cosmetically. Your numbers sound good, assuming your machine's numbers can be trusted, and the welds seem to confirm that.

That said, look closely at the right side... The long steps and short pauses (to make that "like TIG" look) have cased you not to break the edges of the parent metal in almost every gap between steps. If this weld were to be inspected, it would be "looked out" with no further testing for underfill.

I get the desire to make it look like a stack of dimes, but it's more important to fully fuse the metal. I, too, do a step-pause on MIG (unless I have a really secure prop to work from), but I take very short steps to allow for a complete fill before I advance.

Just my two cents...

Steve S

Re: MIG Heat and techniques

Posted: Thu Apr 14, 2016 8:38 pm
by Sethmark
Exactly the detail I'm interested in. Thanks! I like the e weave since it gives me a centered heat and appears to cook in the root best when I've cut and etched the pieces. My employer demands a certain amount of aesthetic in the welds that has nothing to do with strength. My job is to make sure the job is done right and is pretty.

Re: MIG Heat and techniques.

Posted: Thu Apr 14, 2016 11:33 pm
by Otto Nobedder
Yeah, that sucks when the boss has an expectation for appearance that is a direct contradiction to the best way to make it strong.

Steve S

Re: MIG Heat and techniques.

Posted: Fri Apr 15, 2016 9:27 am
by soutthpaw
I would say shorten up your weave. So it's more "stacked" that will fix the problem otto mentioned. Jody did a video on stack of dimes look. No one does it better than ZTFab on welding web. I'm still trying to arrange to visit his shop and be a fly on the wall for a few hrs and watch him weld, get a few pointers.