Welding "black iron" pipe fittings - not pipe?

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Any thoughts on welding hardware store "black iron" pipe fittings? I am trying to make a box screw on to a "black iron" pipe used as a pass thru in a wall. The pipe I welded a flange to earlier and its worked. The catch to that is the pipe, I believe, is regular steel. In this case - the female thread fittings are cast. Hence the question on weldability in the thread... What I want to do is make a mounting plate for the box then line up the fitting with a hole in the box so the pass thru is enclosed in the pipe + fitting + mounting plate + box.
Reply:I believe both black iron pipe and fittings are both steel in which ER70 would work. Sent from my iPhone using Tapatalk
Reply:Will be stick welding. I am thinking 3/32" 6011. I have 6010 and 7018 also, but I think the 6011's being easier to run, low slag, and good penetration would be a good choice. It isn't really a structural weld so the ductility etc with 7018 isn't really needed. The bead might come out "cleaner", but I am not worried about how it looks. I do want to weld all the way around the fitting/plate so there is metal all the way around to seal. It will all be coated, also, so it won't rust easy.
Reply:The make fitting in both steel and ductil iron. I use E71T-1,  E71T-11 or E7018 they all work well.Dave

Originally Posted by FlyFishn

Will be stick welding. I am thinking 3/32" 6011. I have 6010 and 7018 also, but I think the 6011's being easier to run, low slag, and good penetration would be a good choice. It isn't really a structural weld so the ductility etc with 7018 isn't really needed. The bead might come out "cleaner", but I am not worried about how it looks. I do want to weld all the way around the fitting/plate so there is metal all the way around to seal. It will all be coated, also, so it won't rust easy.
Reply:All the black iron pipe and fittings I've ever dealt with was steel and welded fine. YMMV.
Reply:7018 on them. 11 digs, makes for a brittle addmix.www.urkafarms.com
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Originally Posted by StandarDyne

All the black iron pipe and fittings I've ever dealt with was steel and welded fine. YMMV.
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Originally Posted by FlyFishn

Will be stick welding. I am thinking 3/32" 6011. I have 6010 and 7018 also, but I think the 6011's being easier to run, low slag, and good penetration would be a good choice. It isn't really a structural weld so the ductility etc with 7018 isn't really needed. The bead might come out "cleaner", but I am not worried about how it looks. I do want to weld all the way around the fitting/plate so there is metal all the way around to seal. It will all be coated, also, so it won't rust easy.
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Originally Posted by John T

Agree. 7018 and mig went just fine.
Reply:I have never use tig on pipe fittings.I use stick , flux core or brazing. Dave

Originally Posted by MinnesotaDave

Agreed, I've also tig welded on them.
Reply:Thanks for the input. I may tack with 6011 then bead with 7018. We'll see how the tacking goes. That should give me some indication of how things perform. Then if the results are OK I can keep running it or switch to 7018. Though, the "plate" material I have is really thin - around 1/16" I think, mild steel. I don't think I have any more 1/8" with a big enough piece for what I'm doing. I can check - that would be preferable if I can make it work.
Reply:Well I cant figure out how to attach pictures from my phone... In any event - I used some 3/16" plate instead of the 1/16". Im glad I did. It took more heat and I was able to get a decent weld on both the fitting and plate without burning through the plate. I used 3/32" 6011 to tack and 3/32" 7018 for the bead. I ran the 6011 around 80 amps and the 7018 at 100 amps the first round. It was too hot so I backed off to about 80 amps after. There is a good amount of under cut on the fitting on the bead I did with 100a. I tried to concentrate heat on the fitting and let the weld metal wet in to the plate underneath. All in all it came out fine. Im glad the fitting took the weld OK. That makes me happy!When I can get some pictures up Ill post them.
Reply:Another tidbit is I decided to tap the plate so the mounting screws thread straight in to the plate. I like that set up. The plate is still way overkill, but between the welding and the meat to tap and have stronger threads it works fine.






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And the finished product. I tried to "clock" the fitting so that I had some extra tightening to do beyond hand tight where the fitting being tight would be when the box was straight up. However, I think the heat from welding opened up the fitting a bit so it fit a good bit looser. The box would be horizontal at the point it would be "tight". I am hoping once the thread sealant cures that locks things in a bit. The sealant is only there to keep water out/protect the threads, the "pipe" doesn't carry anything like liquid or gas that the sealant has to seal.