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Unistrut welding to thick steel

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Unistrut welding to thick steel

Postby Sjeane89 » Fri Oct 06, 2017 9:56 pm

So guys/gals, the reason i found this forum was particularly for this question. i have tried google searches, searching this forum, and cant find a clear answer on how to go about doing this.

I just started as a structure hand for an electrical company and am being made to weld galv. unistrut onto galv. beams and stuff like that for cable trays. i have done this before with 6013, but the job spec requires 3/32 7018. and i keep blowing holes in the strut. i can kinda do a 6010 style step and it welds completely it just aint too pretty. my forman told me as long as it holds and dont look like some hammered cat $@!#% its fine, i was just wondering if any of you hands had a better way to do it. what kinda weave etc yall prefer to do?

i actually seen one guy on the job laying a 7018 rod (with the flux knocked off) in the seam of the joint and welding over it, may try this next week.
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Re: Unistrut welding to thick steel

Postby Poland308 » Sat Oct 07, 2017 9:42 am

No weave. Just hold a close arc. 3/32 7018 will be at about 70 amps on something that thin. If you can grind off some of the galvanized from the beam that will help as well. Use a file and scuff off some from the unistrut as well. Keep tour welds short about 1-2 inches max.
I have more questions than answers

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Re: Unistrut welding to thick steel

Postby Poland308 » Sat Oct 07, 2017 9:44 am

And travel progression should be upwards in the vertical welds. This will help with slag issues.
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Re: Unistrut welding to thick steel

Postby noddybrian » Sat Oct 07, 2017 3:49 pm

Like they said ! I would add try to keep rod angled mostly at the thick material & only just nip the edge of the unistrut - almost like your welding along side it & just let the puddle wash towards it.
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Re: Unistrut welding to thick steel

Postby Sjeane89 » Sat Oct 07, 2017 6:02 pm

thanks for the replies! i really gotta get used to this machine, its a big blue 400, had it set at 60, and 60 on it is pretty darn hot. i fire up and an inch of the rod blew off, gotta keep the rod burried deep with a super tight arc. the company told me if i wasnt welding on their diesel big blue, then id be carrying around one of those tiny little maxstars. last company i was with, all of our welding was with some old lincolns. just needing to adjust and learn these new machines i think.
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Re: Unistrut welding to thick steel

Postby Poland308 » Sat Oct 07, 2017 8:48 pm

Best bet would be to use the max star and tig it.
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Re: Unistrut welding to thick steel

Postby Bill Beauregard » Tue Oct 10, 2017 10:11 pm

I favor MIG where I can. You will get used to 7018 eventually. Grind off the galv, I like Norton Blaze or rapid strip discs. Spray cold galv. after welding.
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Re: Unistrut welding to thick steel

Postby RamboBaby » Wed Oct 11, 2017 9:13 pm

Sjeane89 wrote:diesel big blue

Yessirreebob, every one of those things I've used seem to run considerably hotter than advertised.
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