Cleaning Rebar?

[Vegaman_Dan]

I like to use rebar in steel fabrication projects around the garage. It's great for making racks hooks when and where I need them. Cheaper than using angle iron or bar stock for many projects.

But this stuff comes coated in a nasty black or brown material (not just rust) that needs to be cleaned off first. I have to then use a wire wheel on the bench grinder to get to bare steel and usable. That's a LOT of labor.

Is there a quick and easy way to take all of that stuff off? Acetone? I don't need it to be shiny, but it does need to be clean and weldable.

 

[readhead]

And you are buying weldable rebar. Right?

 

[Vegaman_Dan]

And you are buying weldable rebar. Right?

I don't know. It's not labeled as anything special. It welds up just fine once I clean it up. Perhaps I'm cleaning off some preservative that gets applied or something.

 

[readhead]

There should be a series of numbers on the rebar. If it is weldable there will be a "w" after the numbers.
Now I know that a whole bunch of people are going to say " I have been welding rebar for years and nothing broke". That may be true but just don't build something that can hurt somebody if it comes apart. The first thing that comes to mind is ladders.

 

[Vegaman_Dan]

There should be a series of numbers on the rebar. If it is weldable there will be a "w" after the numbers.
Now I know that a whole bunch of people are going to say " I have been welding rebar for years and nothing broke". That may be true but just don't build something that can hurt somebody if it comes apart. The first thing that comes to mind is ladders.

Good tip. I never knew there were different types. I'll have to look for this. I've never thought to look for numbers on the rebar itself.

 

[ConCretin]

'Weldable' rebar is designated as A706 and as redhead correctly mentioned, is designated with a 'w' mark on the bar. While you couldn't get away with it on a spec job, welding rebar is fine for non-critical applications. We've welded rebar and tried unsuccessfully to beat it loose with very large hammers. We gave up before the weld did. Here's a pretty good chart or rebar markings

http://www.aspeboston.org/estref/estref-6.pdf

Most big box and supply house rebar is grade 40. Grade 60 is more common for commercial projects.

To your original question, I'm not sure what you are finding difficult to remove from your bars. Most rebar we see isn't covered with anything as you describe - just a little surface rust

 

[mesquiteforge]

Although not the safest and easiest product to use-I have found Ospho by Skyco to be a great product. It is Phosphoric acid and will eat away any oils, paints, and leave only a white residue on the bare metal that you can paint over or wire brush off. Use with caution and follow the instructions. Wear your PPE! Gloves, goggles, and a mask/respirator are not just a good idea-but imperative to your safety.

 

[readhead]

Back to your original question. We use a water based degreaser to clean up new material. Then we will wire brush the material before welding. Some chemicals can have very toxic fumes when welding so be carefully.
As Llwillysfan pointed out and as did I welding nonweldable rebar should be reserved for noncriticle assembly's.

 

[mormit]

Both mesquite and readhead's recommendations are very good.

NEVER use brake cleaner on anything you plan to weld. I'd stay away from solvents altogether.

 

[GarageWarrior]

Muriatic Acid works good for metal prep - cheap and quick, use proper PPE, rinse it off so it doesn't eat too much metal

 

[spotco2]

Sounds like a good excuse to buy a sand blaster to me.

 

[lynnbilodeau]

Muriatic Acid works good for metal prep - cheap and quick, use proper PPE, rinse it off so it doesn't eat too much metal

That's some nasty stuff.

 

[sberry]

HRR cost about the same, easy to scuff clean.

 

[Vegaman_Dan]

Followup: The rebar I had been using was all noted as W for weld compliant. I've read more about the subject online and while yes, you're not going to be using it for anything structural since it's cast in place and then rolled, the steel quality it self isn't terrible. But it does have to be cold bendable and able to withstand the expansion/contraction cycles in concrete, so it's not going to be super strong. It needs to flex.

For my needs, it more than exceeds the requirement.

The rebar at Lowe's is all W rated. It only has a bit of surface rust on it from transporting. It's cleaner than I recall. I've been using a wire brush in a grinder to clean it to shiny levels. Ate up a good brush that way and it was time consuming. The stuff welds just fine the way it is if you clean it off with a bit of acetone. Then it struck me- I'm getting it silver and shiny for cosmetic purposes only. I'll be painting this anyways, so there isn't really much point in doing that. If I really want shiny silver, I could just use silver paint.

D'OH!

Sometimes the obvious is so close it can bite you on the nose.

 

[NUTTSGT]

I've picked up rebar at HD before and it has some oil on it. It seems like they sprayed it after it rusted and does make some nasty **** when you grab it. At home/garage/shop it's no big deal but at the store it does ****. I've cleaned my hands after loading it so I don't get it all over the textured steering wheel of my truck.

I'd probably wipe it down with some lacquer thinner to get the oily **** off of it.

 

[930dreamer]

Bead blast the rebar, it should be clean for a decent paint job.

 

[Charliekilo]

Quote
It's great for making racks hooks when and where I need them. Cheaper than using angle iron or bar stock for many projects.

What is your time worth? Add this to the cost of the cleaning processes sited. Now show me the savings.

 

[cyamaha2007]

Muriatic acid does the trick for me.

 

[CanadaBoy]

Not sure about paint but vinegar will take off rust in a day or so, prob paint as well.

 

[metalmagpie]

Lots of new steel comes with heavy oil. Set it up on sawhorses, put kerosene in a spray bottle, spritz from one end to the other, wipe clean with rags, turn parts, repeat.

If your parts are short you could tumble them in a bucket tumbler to remove rust & scale.

It may be that you are seeing false savings from using cheap material which requires a lot of labor to be ready to use. You might consider buying clean new steel from a local yard. On most projects I've done the cost of steel has been less than 10% of the total cost. Might as well get the stuff that's easy to use. And oily rusty rebar? Wouldn't touch the stuff.

metalmagpie

 

[Speed4Life]

The coating on the rebar is probably cosmoline to prevent excessive rust before use. Same **** they put on new brake rotors. Brake parts cleaner will take it off real quick.

 

[readhead]

Brake parts cleaner will seriously hurt or kill you if you weld on the bar. Rebar does not come with any kind of coating on it. It has to be ready to install when it arrives on the job. Any coating would would reduce the bond of the concrete with the bar.
Where are you getting the bar. Is it surplus? It may have been rejected because of the coating.

 

[Vegaman_Dan]

The rebar had only spots of light surface rust and was fairly easy to clean. Just takes time to wire brush it off. I had been cleaning 10' lengths, then decided to just cut to size and take the cut pieces to the bench grinder / wire wheel where it was quicker.

The only solvent I've used was Acetone when I was done. I know better than to use brake cleaner.

 

[brownbagg]

rebar can be welded but it falls under strict guideline (aws d1.4)

 

[sberry]

Brake parts cleaner will seriously hurt or kill you if you weld on the bar.

Once the brakleen evaps it doesn't hurt to weld it. It is really nasty stuff anyway, I try to use it outside. It is so fine it spreads in a hurry, there is no reason though to stand in a puddle with the welder but,,,, The steel yard has hot rolled rounds for about the same cost as rebar.

 

[Gmonkee]

Is that impurity like a scale covering the metal like cold rolled has?

Millscale is safely wire wheeled off.

 

[Kevin54]

Followup: The rebar I had been using was all noted as W for weld compliant. I've read more about the subject online and while yes, you're not going to be using it for anything structural since it's cast in place and then rolled, the steel quality it self isn't terrible. But it does have to be cold bendable and able to withstand the expansion/contraction cycles in concrete, so it's not going to be super strong. It needs to flex.

For my needs, it more than exceeds the requirement.

The rebar at Lowe's is all W rated. It only has a bit of surface rust on it from transporting. It's cleaner than I recall. I've been using a wire brush in a grinder to clean it to shiny levels. Ate up a good brush that way and it was time consuming. The stuff welds just fine the way it is if you clean it off with a bit of acetone. Then it struck me- I'm getting it silver and shiny for cosmetic purposes only. I'll be painting this anyways, so there isn't really much point in doing that. If I really want shiny silver, I could just use silver paint.

D'OH!

Sometimes the obvious is so close it can bite you on the nose.

If you are buying rebar at Lowes, you are probably getting raped at the cashiers desk. Find a local concrete place close to you and get your rebar from there. For what you pay for one or two 12" pieces at Lowes, you can buy a 10' stick at a concrete/brick place.

 

[Vegaman_Dan]

If you are buying rebar at Lowes, you are probably getting raped at the cashiers desk. Find a local concrete place close to you and get your rebar from there. For what you pay for one or two 12" pieces at Lowes, you can buy a 10' stick at a concrete/brick place.

Likely, but it's $3 for a 10' piece of 3/8" and that's fine with me. My time is not worth saving a few pennies by hitting up concrete suppliers, none of which would be open on a weekend. Convenience has its cost.

 

[FunkyfullWidth]

I think you need to do some custom fabricating. I'm envisioning a grinder with a wire wheel on it... make a bracket or something to hold the grinder sturdy. Wrap a tube/clamp around it. Make it so you can tighten the position and depth of the wheel.. then have a length of tube with a slit or two cut in it and some holes drilled in the bottom and top You can run the rebar through the tube and spray brake clean in there, feed the rebar into the wire wheel. And even blast some air in there. At least I see it in my head.