How To Tighten Black Iron Pipe (Quickly & Easily!)

Stacy Randall
by Stacy Randall

If you have a home built before the 1960s, the odds are good you might have black iron pipe. These pipes were typical for water and gas lines back then, even up until the 1980s. Afterward, more modern homes started using more user and cost-friendly PVC pipes.

Nowadays, people rarely use black iron pipes for water because it tends to rust easily. However, they remain a very durable option for gas, so if your home has gas, it might have these pipes. Therefore, knowing how to tighten black iron pipe is important; basically, you use pipe dope, two pipe wrenches, and avoid over-tightening.

Black iron pipes tend to have some problems with leaks at the connections. So, if your home has them, it’s likely you’ll end up needing to work with them at some point. If you have to repair a leak or replace connections, you’ll need to know how to tighten the black iron pipe.

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What Exactly Is Black Iron Pipe?

Black iron pipes are ungalvanized, malleable steel pipes that you can cut to length, thread, and use in various applications. They get their black color from the iron oxide that forms on them during the manufacturing process.

Up until the 1960s and even the 1980s, people used them in homes for water and gas. However, they quickly lost favor as water pipes since they tend to corrode and rust easily.

They can also be quite challenging and costly to repair; however, they are very durable for gas lines. They are also readily available. Many builders are opting to go back to black iron pipes for natural and propane gas lines for these reasons.

Tightening Black Iron Pipe at a Glance

The act of tightening black iron pipe by itself seems relatively straightforward. You need two pipe wrenches, some pipe dope, and your muscles. The size pipe wrench you choose will determine just how much strength you need to put behind your twist.

For minimal effort, go with a 24” wrench, or an 18” wrench will work well for ½” and ¾” pipes. Basically, you apply pipe dope to the threads of the pipe, making sure to cover it entirely but not excessively. Then, first, thread on the fitting by hand.

Finally, you tighten the fitting onto the black iron pipe using the wrenches. One wrench holds the pipe in place while the other tightens the fitting. Black iron pipe is durable, so you likely don’t have to worry about breaking the pipe with too much tightening.

However, you could risk stripping the threads if you over-tighten the connection. Therefore, tighten to the point where you can’t turn it anymore, then leave it be.

Check for Leaks; Prepare to Call a Pro

Afterward, test the connection for leaks.

If you notice any issues, tighten the connection a bit more using two hands on the wrench for more strength. Again, don’t force it.

If you still have leaks, you may need to repeat the whole process or call a pro. Repairs concerning black iron pipes can be potentially daunting and get costly, so keep this in mind.

How to Install and Tighten Black Iron Pipe

If you decide to install a black iron pipe, be prepared for a time-consuming process. Unless you have 100% confidence in your DIY skills, it’s best to call a professional, especially where working with gas is concerned.

If you press on with doing it yourself, contact your local authorities first when dealing with gas pipes. You want to ensure you follow all local codes, not just for legal reasons but for your safety.

Tools You Need for the Job:

  • Pipe cutter with rotary blades
  • Pipe threader
  • Cutting oil
  • Pipe vise and stand
  • Bucket and screen strainer
  • Rags
  • Two pipe wrenches (at least 18”)
  • Necessary amount of black iron pipe and correct fittings
  • Pipe deburring tool
  • Teflon tape (optional)
  • Pipe dope (pipe joint compound)
  • Gas-Leak detector
  • Tape measure
  • Gloves and safety goggles
  • Pipe strapping
  • Water and dish soap
  • Air compressor

Step 1: Turn Off the Gas

Safety first! Put on your gloves and safety goggles. Before you proceed with any repair or replacement, shut off the gas.

You can use a gas leak detector to ensure the gas is off (don’t just rely on your nose).

Step 2: Measure and Cut the Black Iron Pipe

Measure the length of pipe you need, measure out the pipes and prepare to cut. Use the vise to hold the pipe still so you can cut it with the rotary blade. Use cutting oil to protect the blade.

You can use a bucket and strainer underneath your work area to catch excess oil to reuse. Alternatively, at least lay down a piece of wood or some other material to make cleanup easier.

After cutting your pipe to the desired length, use the deburring tool to smooth out the cut end.

Step 3: Thread the Black Iron Pipe

Use the pipe threader to thread the pipe, making sure to use the correct size die. Use cutting oil to protect the die.

Turn the handle a half-turn at a time, with the die over the pipe’s end. Continue turning this way until the thread matches the die’s thickness. Hold the pipe vertically after cutting to loosen any pipe shavings, and use a rag to wipe the threads carefully.

Step 4: Attach Pipe Fittings and Tighten the Black Iron Pipe

Using the proper fittings, start making your connections. Use the rag, or a small brush, to apply pipe joint compound (or pipe dope) to the threads. Apply the compound to the threads of the pipe as well as inside the fitting.

Place the fitting onto the pipe and tighten it by hand. If you don’t use pipe dope, then you need to use Teflon tape at least. If using tape, wrap it in a clockwise direction, facing the pipe’s end. Wrap the tape around the pipe between 4 and 6 times to create a good seal.

Using pipe dope or pipe sealant tape is vital since it’s what prevents leaks. If you use a pipe joint compound, sometimes you will notice tiny bubbles in the compound near the connections. These bubbles can signal a leak, a sign you wouldn’t get with tape.

After tightening by hand, hold the pipe in place with one of the pipe wrenches. Use the other pipe wrench to tighten the fitting. Keep turning until you can’t go any further.

Step 5: Check for Leaks

Before going any further, check your work. KEEP THE GAS OFF. You can place some water mixed with dish soap onto the connections then run air through the line with an air compressor.

If there are any bubbles at the joints, this signals a leak. If this happens, it means you would be leaking gas, and no matter how small, that’s never okay.

You need to redo your fittings. If no leaks are present, you can move on to the next step.

Step 6: Secure and Support the Black Iron Pipe

Use pipe strapping to secure the joints to floorboards or other supports roughly every 6 to 8 feet. It’s vital to carry out this step since black iron pipe is very heavy. Once you’ve placed all your supports, you can turn on the gas supply.

As an extra layer of precaution, use a gas leak detector to ensure there are no issues with your connections. If at any time you suspect a gas leak, shut off your gas immediately and exit the area. Once you’re in a safe location, call your local authorities and gas company.

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Related Questions

How is black iron pipe different from steel pipe and galvanized pipe?

Steel pipes are very durable and long-lasting, plus they do not rust as easily as black iron pipes. You can typically find steel pipes in industrial applications, oil lines, and water treatment facilities. Homes near water also often use steel pipes since they aren’t as prone to rust. But, steel is costlier than black iron pipe (by about 20%). But, it saves in the long run because it’s more energy-efficient. However, in the US, black iron pipe is more accessible than steel, making it more convenient.Black iron pipe also consists of steel (low-grade steel) but is more malleable. It’s also more prone to leaks since it uses seams and connectors, whereas you weld the connections in steel pipes. Also, as mentioned previously, people rarely use black iron pipe for water applications anymore.  Galvanized pipe features a zinc coating, making it a bad choice for gas lines since the coating can flake and clog the lines. But, galvanized pipe is not as prone to rust as black iron pipe. 

What is the life expectancy of black iron pipe?

Depending on its environment, black iron pipes can last anywhere from 50 to 100 years. 

Are there other uses for black iron pipe?

Many people have found black iron pipes to be good for building creative and unique furniture pieces. It’s especially great for those seeking out rustic or industrial looks. You can combine it with other elements like different woods to create various styles.

Stacy Randall
Stacy Randall

Stacy Randall is a wife, mother, and freelance writer from NOLA that has always had a love for DIY projects, home organization, and making spaces beautiful. Together with her husband, she has been spending the last several years lovingly renovating her grandparent's former home, making it their own and learning a lot about life along the way.

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