How To Bend Rebar (Quickly & Easily!)
Many do it yourself concrete projects require reinforcement in the form of rebar. This steel reinforcement material comes in long straight sections that must be bent to fit into the concrete forms correctly. There are several ways to bend rebar to create simple or complex shapes for your concrete project.
The easiest way to bend rebar is with a power rebar bender. For small projects using smaller diameter rebar, manual benders are available for rent or at reasonable costs. It is possible to bend smaller diameter rebar by hand without special tools.
There are several considerations to be made when bending rebar. The biggest factor is the diameter of the rebar. Another factor to consider is the intricacy of the shape you need for your project. For most do it yourself projects, the projects’ size needs rebar in diameters that can be bent manually.
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Bending Rebar by Hand: Simple Methods for Simple Projects
Most homeowner projects that need rebar reinforcement are small enough that the rebar can be bent by hand or with a few simple tools. In most cases, the diameter of the required rebar is less than ½ inch. The shapes are also usually simple, often a simple square, rectangle, or grid.
This smaller rebar and simple shapes lend themselves to several manual techniques such as:
- Clamping the rebar in a vice
- Use two pieces of pipe to create the bend
- Build a homemade bending jig
- Buying or renting a manual rebar bender
The Basics of Bending Rebar by Hand
To bend rebar safely by hand is relatively simple and can be done safely by following a few rules.
Rule 1: Secure the Rebar
Rebar, because of its round shape, tends to want to roll, turn or slip while bending. For a successful and clean bend, you must secure one side of the rebar to prevent movement as you make the bend. The quickest way to get a good grip on a length of rebar is a vice securely mounted to a sturdy work surface.
Rule 2: Wear Your Safety Equipment
Always protect yourself when bending rebar. Eye protection is a must. High-quality leather work gloves are necessary, as well. Some rebar is coated with zinc. This galvanized coating can flake at the bend and fly in unexpected directions.
Rule 3: Never Heat Rebar when Bending
Heating rebar can change the tensile strength of the steel. If your project depends on the rebar for structural strength, heating can cause the rebar to become brittle. Heating could lead to fractures that weaken the rebar and compromise the integrity of your project.
Rule 4: Avoid Hammers
Using a hammer or other object to pound your rebar into shape can have serious consequences down the road. Hammering on the steel can weaken the metal at the bend and where the hammer blows occur. If you are using coated rebar, the hammer blows can damage the coating leading to rust and corrosion.
Understanding Rebar: Know What You Are Working With
Before you start bending rebar, you should understand the material with which you are working. There are many variations in the materials, quality, and coatings used on rebar. Using the right rebar for your project is important, as is the way you bend it.
The Types of Rebar: More than Meets the Eye
Each of these types of rebar has characteristics and requirements for bending, cutting, and tying. As you build your rebar reinforcement forms, you should consider these requirements.
- Carbon steel rebar is low-cost and is the rebar most easily found in the big box home improvement stores. Often call Black Bar, it is a good combination of cost and tensile strength.
- Epoxy-coated rebar is Black Bar with an epoxy coating to resist corrosion. Epoxy coated rebar offers the same tensile strength as Black Bar but at an increased cost for the epoxy coating. Bending epoxy-coated rebar is more difficult to keep from damaging the coating.
- Galvanized rebar is the better choice for corrosion resistance. The galvanized coating on the bare is up to 40 times more resistant to corrosion than epoxy-coated rebar. Unfortunately, the galvanizing process adds approximately 40 percent to the cost of the rebar.
- Stainless steel rebar is the highest quality rebar available. Rebar made of stainless steel is much more corrosion resistant than any other steel rebar type. Resistance to damage is also greater. Fortunately, stainless steel rebar is no more difficult to bend than any other type of steel rebar.
Manually Bending Rebar Using Pipe
It is possible to bend simple shapes of smaller diameter rebar using two pieces of pipe. Following a few simple steps can be the key to making good bends in smaller diameter rebar quickly and easily.
Step 1: What you Need
The basic tools for bending rebar with pipe include
- Two pieces of pipe. The pipe you chose should be galvanized pipe with thick enough walls to handle the stresses. If you have carpenters’ pipe clamps, these are perfect.
- A tape measure
- Marking tools such as chalk or pencil
- Gloves and eye protection for your safety
Step 2: Mark your Work – Get the Bend in the Right Place
Measure the rebar and make a mark where you want the bend. The mark should be in the center of the curve you will create.
Step 3: Slide the Rebar into One Pipe
Slide the rebar into one of the pipes. Position your mark just outside the end of the pipe. How far you leave the mark outside depends on several factors. The rebar’s diameter, the rebar’s hardness, and the diameter of the pipe you are using all influence where to put the mark.
Step 4: Position the Second Pipe on the Rebar
Slide the second piece of pipe onto the rebar. Make sure your mark is still in the proper position with the first pipe. Place the end of the second pipe at the same distance from your mark. Equal distancing will ensure that your mark is in the center of the bend.
Step 5: Make Your Bend – Slow and Careful is the Key
Make the bend in your rebar by lifting the second pipe slowly and carefully. Watch out for slipping. You must maintain the position of the rebar with the two pieces of pipe. You may need to bend the rebar just past the angle you need. The steel rebar will have some spring and may rebound a bit.
Step 6: Check the Angle of the Bend
Use a protractor to check the angle of your bend. If necessary, make adjustments until you have the correct angle for your project.
The Downsides of Manually Bending Rebar
There are a few caveats to bending rebar manually. For most homeowner do it yourself projects, these are not problematic. However, if your project depends on the rebar’s structural integrity, you should know these issues.
The Radius of the Bend
Bending rebar manually with pipes or in a vice can create bends with an inside radius that is too small. Bending too tightly can weaken the rebar outside the bend, resulting in fractures in the steel.
Damage to the Rebar
If you use a pipe to bend rebar, the pipe’s sharp edges can nick or gouge the rebar’s steel. Nicks and gouges in the rebar can weaken the rebar
Damage to the Rebar Coatings
It is hard to bend rebar with pipes or in a vice without damaging any coatings. If you must bend coated rebar manually, be sure to repair any damage to the coatings.
The Better Alternatives
If you are bending more than a few rebar pieces, it may be worth your while to rent or purchase a manual rebar bender. Most of these manual benders allow you to bend thicker rebar as well as make more intricate shapes. Making multiple bends on the same length of rebar is also much easier with a manual bender.
The Tool Must Match the Job
Bending tools create a proper bend of the right size for the thickness of rebar. Make sure that the rebar tool you are using fits the rebar you want to bend. If you are renting a rebar bender, the rental agent is a good source of information about sizing the project’s tool.
Take the Time to Inspect Your Work
In most cases, rebar benders do much less damage to rebar coatings. However, you should inspect each bend for damage to the epoxy or galvanized coating on the rebar. Repair the damage to the coating to ensure that your rebar is properly protected.
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Getting the Job Done
In the end, for most homeowner do it yourself projects, there are tradeoffs. In the case of bending rebar for your project, a bit more work and less expense may be a great tradeoff. It is certainly possible to bend rebar for small projects by hand.
We hope that this article is useful as you proceed with your project. Remember to take your time, inspect your work, be safe, and have fun!
Dennis is a retired firefighter with an extensive background in construction, home improvement, and remodeling. He worked in the trades part-time while serving as an active firefighter. On his retirement, he started a remodeling and home repair business, which he ran for several years.
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