Rebar is generally made from the lowest quality steel available, and if it isn't certified one stick batch might have very little to do with the next in mixture from what I understand

 

Rebar comes in several grades and hardness's. How hard the rebar is often effects how well it will weld. I've had bar so hard it strips the teeth right off a hacksaw blade and when you cut it with a bar cutter it "snaps". Softer rebar that cuts like butter in the bar cutter seems to weld better. High tensile high carbon bar doesn't tend to weld well in general.


I've also noticed over the years that rebar seems to have gotten softer in general compared to bar I worked with say 10 years ago.

 

Rebar comes in several grades and hardness's. How hard the rebar is often effects how well it will weld. I've had bar so hard it strips the teeth right off a hacksaw blade and when you cut it with a bar cutter it "snaps". Softer rebar that cuts like butter in the bar cutter seems to weld better. High tensile high carbon bar doesn't tend to weld well in general.

I just bought 50 lengths of #3 rebar for a project I'm doing to make tomato cages for a family member.

To make the cage parts, I had to cut 450 15" sections from the bar, and I figured the cheapest way to do this was to use a bolt cutter (why waste bandsaw blades?).

I can say after a day's worth of backbreaking cutting that the variation is ridiculous, and that is even within the same bar. One side may snap, another may smush. There is a reason that rebar and bed frames are thought of as the sausage of the steel world.

That being said, so far, it all seems to TIG weld the same with ER70s-2. Lousy, but good enough for my purposes.

 

I made a door out of rebar a while back, it was a lot harder to cut than to weld but at the time all I had was a 7" grinder with cutting disks and it took about 30+ seconds to cut all the way through 1/2" rebar. I had 4, 72" bars going vertical and one bar every 5" horizontal. The welding was actually extremely easy. An instructor at school was telling me rebar has no structural strength and said I shouldn't weld with it.

 

What are you trying to weld it with? I used to weld rebar for the steel mills. You need to use 7018 or I found ER70S-6 hard wire works.

 

What are you trying to weld it with? I used to weld rebar for the steel mills. You need to use 7018 or I found ER70S-6 hard wire works.

I was using 6011, I don't have a rod oven so I don't usually buy 7018

 

the Rebar weld test procedure calls out 8010 rod for welding
Its a hard test and have only had 3 people pass it over the years at the CC

 

I didn't know that. But I did manage to weld them together with 6011, I had to slow down to a crawl and get the joints almost white hot to do it, but it happened.

 

Welded plenty of rebar. Always used 7018 stick rod.

 

I tried 6010, 6011, 6013, and E71T-11 FCAW-S, they didn't work for me. My specialized test for the "chicken ladders" I used to weld up is simple. After I weld one, I throw it up in the air, as high as I can, and if it breaks when it falls, it failed.:cool2: No joke, I tried using a bunch of 6013 I had and I tossed them in a pile. After welding about 100 ladders, I went to load them on the trailer and a whole bunch broke apart.:realmad::angry: So I rewelded them with 7018 and started periodically testing them by throwing them up high. Problem solved. The 7018 and hardwire were the only welds to pass the test. Don't worry about storing the 7018. This is not critical, and the first time I welded the ladders, I was given plastic paks of Hobart 418 rod that were not sealed. The guy got them off the bargain table at a Praxair.

 

My wife's teaching partner needed a shut off tool for her sprinkler system, so I got some rebar out and cut and welded it up. I used my MM210 with .030 wire. Weld looked really nice. I painted it, and just before I got ready to take it to her, it fell off the bench and the handle broke off. I redid the job and so far it's holding up fine. Anyone who thinkls bed frames are nasty needs to try rebar.

 

Try heating to a red hot, then weld.

 

I don't have any way to do that. I have a welder, a brush & chipping hammer, a vice and a few clamps.

Holding two pieces of rebar together with my index and middle finger while getting the metal red hot is a fun experience. My glove almost caught on fire.

 

I have some really thick rebar (1") and 1.5" that I've used to weld up frames holding thick 1" or 2" thick plate. I've used 6010's 6011's and 7018's and I've never had a problem with either one. I've made a few wood burning stoves and I make a bottom wood grate out of various sized rebar thicknesses. So far, I've hadn't had any welding problems.

If anything, I think the rebar is soft and I usually have to turn the heat down if I compare say, a 1/2" diameter piece of rebar to the same sized piece of cold rolled mild steel. The rebar tends to melt at a lower temperature when welding. When cutting, I don't like using a chop saw. I usually use plasma or O/A in the past.

I LOVE working with rebar. :cool2::cool2::cool2:

 

I love working with it also, it welds really easily I think. I hated when I first started working with it because I didn't have any way to cut it other than an angle grinder like I said in my previous post but once I got my torch it cuts through it in just a few seconds instead of a cutting wheel taking 30 seconds to cut one piece. I used some 11018 that had never seen the inside of an oven and a door I made is still holding up strong ( it weighs easily 50-75 pounds ) It took me about 2 days to make it, I cut it all up one day and made the frame and then welded it up the next day

 

These were 20' lengths, but thanks. I feel a little better now. LOL.

 

We had a real bar cutter that would take either 5/8" or 1/2" bar ( 2 cutting notches). It was always a laugh to see the one laborer hanging from the 6' length of pipe we added to the handle so we could cut 2 pieces of 1/2" at one time. He'd be hanging upside down with his arms and legs wrapped around the pipe trying to bounce up and down to get it to cut. Everyone would stand around and wait to see if it mushed, or snapped and dropped him to the ground. :laugh:



I will say one thing, if you heat it up and quench it it gets super hard. Learned that the hard way using some rebar to practice with my forge. new bar cut like butter with a hack saw into manageable size pieces, but later when I wanted to cut off the finished piece the hacksaw wouldn't even scratch it. Also I had a few pieces "shatter" when I worked them too cold. I'd be pounding on the anvil and hear a "ping" and the whole end I'd been working on snapped off and went flying off who knows where in the shop.

I welded up some quick archery arrow holders last Friday using some 1/2' rebar with 6011. Nothing I'd brag about, but good enough to hold the small 2" pieces of pipe to the vertical so the kids didn't walk all over the arrows like they were trying to do the week before.

 

If you look carefully the rebar that is rated for welding will have the word "weldable" imprinted on it.
The other grades are really not weldable unless you use lots of preheat and let the weld cool in still air. Even then there is no guarantee that the weld will not be brittle.

 

It's not for anything important, so it isn't critical that the welds aren't brittle. But just in case I'll weld struts on the legs.

 

I only welded rebar once on a construction project. It was in a foundation cross-tie for a steel shed type building that spanned about 100 ft. I don't know the grade of rebar, the rod used or the settings. I was just a kid assigned to carry rebar and the welder let me do some welding for the first time in my life.

I think the building is still standing after 40 years, so I guess I did OK.