Welding Galvanized Steel Tubing

[saphman]

I recently acquired some 2" Galvanized Steel pipe in 6 foot length(s). I am trying to build some Steel saw horses and tried to weld some of this stuff with an AC 225 arc welder and various types of rods for practice. Despite using 6011, 6013, and AC7018, i was unable to create clean welds on it and actually "Blew" through some of the tubing rather than welding it. I even tried very low amperage settings. Do you think it is my welder or is this material to thin for Standard arc? I would say the metallic thickness is 1/8-3/8 in. Thanks

[vipermanz]

On low it sounds like you were about perfect on the amps for the thickness, If galvanized isn't clean it acts up pretty bad. Try removing the galvanizing in the area you are welding with a Wire brush or sanding it off. It will help you out

[DDA52]

You should be able to get acceptable beads WITHOUT cleaning anything on normal galv coatings. It is is very thick like a hot dipped galv, you may need to remove it. 1/8 6011's with around 75-90 amps should fill the bill. Use a whipping action and move quickly enough to get a good bead, but not burn through. They will dig enough to clean out the galv and give solid welds.

If you could post a pic, it would help diagnose your troubles. If possible, note the settings also.

[saphman]

Thanks for the help. I will send along some Dig Pictures. I am using a Lincoln AC 225 Arc Welder. My Amp settings were as low as 40 A and as high as 90. Either setting gave poor results with blowout of the steel.
This type of tubing is used frequently as posts for chain link fences. I have heard that the only way to weld this stuff with quality is with DC or Mig.

[shortarc]

I have welded some of that chain link fence stuff and most of it is real thin.

You will have to do a real fast whip or use wire, flux core works real well on galv.

PS Don't breath the smoke!

[DDA52]

Ok, now I see the problem. That is probably 18 ga tubing. Some is 16 ga. You need to go way down on the amps with it, say 50 to 70 range with 1/8 6011. If you are using 3/32, 40 to 60, same rod. Some prefer 6013, but I don't. You could try it. Most 6013's like the heat a little hotter than 6011. If you get incomplete beads, turn it up and move like lightning.....that's why I don't like them.

[Jeffl]

I am trying to remember something about zinc oxide.
That coating should be removed around the weld area.
I hope my memory serves me well.

[saphman]

Thanks Folks! For all your good input. Would I get the same results with a wire welder? Am I at a significant dis-advantage just having the Old Red Ac-225 Tombstone to work with?

[billfen]

The fumes from welding galvanized are very toxic. Be sure to have plenty of ventilation. I usually grind off the galvanizing to reduce the fuming.

[MPK]

6011 is most likely the best rod for this. For Mig it has to be ground clean. 6013 doesn't seem to burn through the galv.

[DDA52]

For your tombstone, 6011 is the best choice. 6013 will do it, but it will need some significant heat to get through the zinc to base metal. 6011 has all the elbow grease it needs at reduced heat. If you want to go with wire, fluxcore is the ticket. It will act just like the 6011's as regards the coating. There is no need to remove it with F/C or 6011. Just keep your head out of the smoke and weld away. I made a living doing it exclusively ( galvanized sheet metal ) for over 10 years. Milk before and after will help also. Do it outside and if there is no breeze, use a fan. Common sense will prevent a lot of problems.

[saphman]

DDA52, Thanks. Did you stick weld this stuff with AC or did you use DC? This tubing is pretty thick for chain link uprights, I'd say 2-3/8''. I will try Grinding off the Zinc and see what happens.

[DDA52]

Both. When I first started out, they were putting ac tombstones on the jobs for us to use. Later, they got us some bigger machines. When I went out on my own, I was using a Miller engine drives most of the time. The vast majority was all DCEN. I was welding 16 ga sheet with 3/32 6010's at 55-60 amps.

[rockytopp]

Any time I do galv. pipe such as your useing I take the Ox. torch and burn the galv. off. around where I am going to join the joints. I use a fan to blow the fumes and try to do it out side also in the bench vise. then you can weld it up real slick. I like the 6011 and small rod and about fifty heat. range. works for me.

[rusted]

The first welding beads I ever made were on galvanized plate. I posted pictures of my proud work on the internet and was promptly trounced for welding on toxic materials.

There are only two safe ways to do this: Use a welding mask with a remote air-source, or grind away or otherwise remove the galvanized coating from your heat affected zone before you start.

[saphman]

Does it matter whether you use AC or DC?

[DDA52]

No, it doesn't. When I was burning the stuff, we used AC and DC in every situation imaginable. It was mostly stick with a tiny bit of fluxcore thrown in for good measure. I used AC a time or two with my Bobcat even. There was this misc. iron company in Md. that used diesel Bobcat type machines in the late 80's. Every time I was around those dudes, my machine would develop a serious case of arc blow. To cure it, I used AC .....reluctantly. I never could get Miller to tell me why that was happening. They probably didn't know either. It'll weld with both currents. It is easier to weld with DC, though. Everything is. AC will make you a better weldor, though. If you can pass a test with an unstable arc like that of AC, you can pass with anything.

Galv is just a coating that too many people are afraid of because of stuff they read or heard. Blame it in the internet, if you like. You can weld galv all day with ZERO side affects if you use your head. Don't breathe the smoke and weld in confined places without adequate ventilation. Those two things will prevent 99% of any problems. We couldn't burn or remove the coating under any circumstances. It was put there for corrosion resistance. We even had to recoat the burned area with cold galv. It has to be welded around the world on a daily basis. All those weldors aren't dropping dead or having appendages fall off, are they? Of course not. They just use common sense and stay away from the fumes. FWIW, there are way more toxic substances when burned than zinc. Try welding something with a few parts per million of phosgene....no better not. That much exposure can be fatal.

Here is an example of the stuff I did. I'd still be doing it, but there doesn't seem to be a need as much.

[rusted]

DDA52 is right though, I suffered no ill-effects from doing it, I never breathed a lungful of the thick smoke produced.

http://www.iza.com/zwo_org/Applicati...alv/030609.htm

Basically it says, remove the coating before proceeding, but if you can't, go ahead and exceed OSHA consumption limits on zinc-oxide and lead. LOL

Of course, I have to wonder, taking into consideration the fact that you will burn the galvanized coating away from the HAZ, and have to reapply a coating when you're done, why not grind it off in the first place and save yourself some possible health hazards? Takes time I guess.

[DDA52]

Rusted
We never did anything but hit them with a wire brush, either by hand or grinder, then re-apply liberally. It is hard to do when you are 300 feet off the deck! Do too much and.......can you say SPLAT?

BTW, most of my beads were under two inches long except at red iron tie-ins. I got very good at holding my breath untill my hood was up.

[John T]

Saphman,
I am also a Newbe welder,
One of my first projects was welding together 2 lengths of galv. pipe,
pretty much the same thing you are trying.

I used my Lincoln AC 225 buzzbox with a setting of 75 and a 6011 1/8 rod.
I burned through a couple times at 90 , but 75 amps and moving quick did the trick.

I'm glad to see I'm not the only one Learning on a stick welder.
Myself, I want to learn stick first. Pay my dues , so to speak.
Then move on to Mig when I am good enough.

Hope I helped some.
-John

[saphman]

John, Thanks for your feedback. I have found that grinding off the zinc coating is helpful and using a real thin welding rod at low current is best. I do think Mig is the way to go and that will be my next purchase