WELDING BLACK IRON PIPE

[brimfield]

What is the best way to weld up Black Iron? Can brake or carb cleaner be used to get it clean enough to weld and what is the best rod for it. I weld on rare occasions just for home projects..

 

[Yomax4]

Rod depends on what the application is. What ever you do, don't weld over brake-kleen. some of it is poisonous.

 

[Lis2323]

I would just grind the weld area (and a spot to attach your ground clamp) shiny.

 

[cwby]

From a web search -
The chemical in the brake cleaner is Tetrachloroethylene. When this chemical is exposed with excessive heat and argon (used in MIG and TIG welding) it also produces phosgene.
Phosgene is BAD stuff.

 

[Motox]

What is the best way to weld up Black Iron? Can brake or carb cleaner be used to get it clean enough to weld and what is the best rod for it. I weld on rare occasions just for home projects..

Not sure what you are trying to build but I would do a few test pieces. Lis2323 mentioned grinding to shiny metal and I would start with a 5P+. If that's not satisfactory talk to your local welding shop or supply store. They usually have some good suggestions.

 

[Aczlan]

I would just grind the weld area (and a spot to attach your ground clamp) shiny.

That or use the wire wheel on the bench grinder to get it shiny, otherwise whatever rod you are used to should be fine. Its called iron pipe, but the pipe is actually steel, not iron (fittings may be iron though).

Aaron Z

 

[Gary Fowler]

I also am not sure what you are calling black iron. A lot of cast iron drain pipe is "black iron" and wont be welded with a 6010 rod. You might get by with a 7018 if it doesnt crack after welding but a nickel based rod specifically for cast iron is what you would need to use.

Regular steel pipe (ASTM A 53/106) can be welded with any of the 60xx rods very easily. For DC welding, use the 6010 for the root pass (you can weld it all the way with these rods also) then switch to a 7018 for fill and cap. This gives you the strongest weld.

 

[kayco53]

Stay away from the brake cleaner like another poster said.

 

[welding seabee]

Brimfield has not responded on his projects and success with his black iron pipe which I am sure is just plain old mild steel pipe.

Obviously, Gary has done miles of steel pipe like I have. No special cleaning is required. Schedule 20 and larger wall thickness, you need to bevel and multi pass, that cleans up the ends and the root area with the grinder. Some pipe has a black coating on it for rust preventing in storage it just burns away and no problem. Rusty stuff, hit with a wire brush wheel on your grinder, if heavy, hand wire brush works OK on light rust. Old rusty stuff for non-critical work I just use 6011 o AC or + electrode on DC. 6011 is the go-to rod for rusty, dirty, painted stuff. Great field repair rod. I also use 6011 for galvanized pipe. DO NOT weld galvanized where you can breathe in the fumes. You will be sick for several. days with zinc oxide poisoning. Inside a building you need to have an air suction device close to where you are working. If you want a fire use you vacuum cleaner. Not a good idea unless it is clean. I try to do it outside when possible.

I got tired of changing wheels on the grinder so I bought 4 cheap HF 4" ones. One has 1/4" grinding wheel, one gas a cut-off wheel, one has a wire brush, and one has flap wheel. They hang on the back edge of my welding table where handy plugged in and ready to go. At $10 apiece the grinders are throwaways. Thinking about replacing with battery units to eliminate all the cords. Have one I keep a thin cut-off wheel on for quickies outside.

Ron

 

[Chanceywd]

Brimfield has not responded on his projects and success with his black iron pipe which I am sure is just plain old mild steel pipe.

Obviously, Gary has done miles of steel pipe like I have. No special cleaning is required. Schedule 20 and larger wall thickness, you need to bevel and multi pass, that cleans up the ends and the root area with the grinder. Some pipe has a black coating on it for rust preventing in storage it just burns away and no problem. Rusty stuff, hit with a wire brush wheel on your grinder, if heavy, hand wire brush works OK on light rust. Old rusty stuff for non-critical work I just use 6011 o AC or + electrode on DC. 6011 is the go-to rod for rusty, dirty, painted stuff. Great field repair rod. I also use 6011 for galvanized pipe. DO NOT weld galvanized where you can breathe in the fumes. You will be sick for several. days with zinc oxide poisoning. Inside a building you need to have an air suction device close to where you are working. If you want a fire use you vacuum cleaner. Not a good idea unless it is clean. I try to do it outside when possible.

I got tired of changing wheels on the grinder so I bought 4 cheap HF 4" ones. One has 1/4" grinding wheel, one gas a cut-off wheel, one has a wire brush, and one has flap wheel. They hang on the back edge of my welding table where handy plugged in and ready to go. At $10 apiece the grinders are throwaways. Thinking about replacing with battery units to eliminate all the cords. Have one I keep a thin cut-off wheel on for quickies outside.

Ron

I do the several HF grinders too. I liked the one that had the switch on top not the side but have been unable to find that one. I have arthritis in my hands and it just worked better. Anyhow the last time I bought a couple of the side style I took a quick look and just by removing the 4 screws I could rotate the body and put them back in. Now I have the switches where I like them. Some minor vent is wrong but it works.


Bill

 

[Gary Fowler]

I do the several HF grinders too. I liked the one that had the switch on top not the side but have been unable to find that one. I have arthritis in my hands and it just worked better. Anyhow the last time I bought a couple of the side style I took a quick look and just by removing the 4 screws I could rotate the body and put them back in. Now I have the switches where I like them. Some minor vent is wrong but it works.

Like others here, I have multiple grinders with various attachments that allow me to grind, cut, sand and polish without changing wheels. I have an assortment of brands. In the 4.5" size, I have 2 HF Chicago Electric with paddle switches (I prefer paddle over the push button), 3 Dewalt (had 4 but one recently bit the dust), 1 Hercules 6" and 1 Hercules 7-9" with safety guards for each size. I also have one Earthquake 20 Volt battery powered one that I use when 110v power is not readily available. This may seem like overkill but you can never have too many grinders (or welding machines--I have 4 of those)

 

[welding seabee]

What I should have said in my last post was that; in my old days; we always butt welded 2" and smaller, Schds 10 through 80, with an O/A torch. One pass around and no cleaning of welds. Only needed one grinder to bevel and clean up O/A cuts.

Today O/A is becoming a lost art, that small pipe is now TIG/MiG welded in the thinner stuff and Socket welds for the heavier. The UA union shops up here (Pacific Northwest) don't even teach O/A welding and cutting any more. O/A was a big labor saver, we could do 3 O/A welds to 1 Arc welded butt joint.

I was always a better O/A welder than arc welding. I have welded up to 12" pipe with O/A. I once did 75 horizontal O/A welds on 6" sched 40 risers on the back side with 2" clearance from the wall. Old wood frame 4 story bldg and the fire dept forbid arc welding and grinding anywhere. That was a real B***H, hot work. Welded in a tee shirt.

Basically, I normally dispatched as a commercial/industrial refrigeration fitter and later as an industrial pipefitter. O/A welders like me were not in big supply for ready dispatch as we were seldom out of work. For 25 years, I never applied for Un-Employment, and drew Foreman or General Foreman pay, even when just another fitter as jobs wound down. My welding skills kept me on projects down to close out. Then I went to work for Navy civil service, retired, and then wandered into Commercial/Industrial Military contractor project management.

Ron

 

[efred]

What is the best way to weld up Black Iron? Can brake or carb cleaner be used to get it clean enough to weld and what is the best rod for it. I weld on rare occasions just for home projects..

I've always had a liking for 7018: it welds through grease, rust, even its own slag. It's designed for welding dissimilar metals. It will weld spring steel to anything.

 

[Gary Fowler]

I like the 7018 also, but, it is very susceptible to porosity if not welded over clean metal. Rust & grease are the worst things to weld over with 7018. 6010/6011 have better compatibility with contaminates without suffering weld quality. As always with any welding process, clean metal is much easier to weld AND you get better quality welds when everything is clean. Welding over slag is always an iffy proposition, it may burn out but it may also become entrapped causing a weakened weld in that area.

 

[Chuck1225]

Most steel pipe is made with 80,000 psi tensile strength steel. You can weld it with weaker metal, such as 60 or 70,000 psi material, but if strength is the issue, use an 80 rod. In stick welding, I use 8014 because it is easy to use and produces a strong weld. Not all tubing is 80,000 psi. Make sure that the pipe has no water in it and no significant rust on the surface. When heated up by welding, rust breaks down to steel and free oxygen. The free oxygen will leave bubbles in your weld. If you are welding with a TIG welder, you can dab a small amount of aluminum rod on the surface once the metal is molten. The aluminum is so electronegetive that it will rob the rust of oxygen and pull oxygen out of molten steel, giving you a weld with no oxygen bubbles.

 

[MrCreosote]

There is only one way to weld cast iron: Oxy-acetylene with cast iron rod. (welding is fusion)

Preheat entire part or far from the weld area with torch. If can't do entire piece, the distance from the weld is greater the thicker the section.

• Electric
  • Ni-rod for more strength, Use needle descaler to peen weld as soon as completed to reduce shrinkage tensile stress which will crack the cast iron
  • Silicon Bronze - lower melting point, lower tensile strength means less crack risk
• Oxy-Acetylene
  • Fusion using cast iron rod is possible - I'll just put it out there. Works well and is nowhere near as short as aluminum. However preheat has to be substantial along with slow cool down.
  • Braze
    • Brass brazing rod - may flow/wet better
    • Silicon Bronze - may be less crack
  • Solder: cast iron solders just fine. Depends on how much strength you need.