Tips for Welding a Catalytic Converter: Everything You Need to Know

A catalytic converter is a part of your vehicle's exhaust system that absorbs some of the hazardous pollutants produced by the engine's ignition. A converter's mesh structure can crack, resulting in a harsh banging noise from the inside exhaust pipe.

As a consequence, your car will most possibly lose emission standards, necessitating the installation of the new catalytic converter to the exhaust system. After extensive surface cleaning, a catalytic converter could be welded using MIG and TIG welding. To connect a new converter to previous exhaust tubing, welding is a suitable alternative.

Selecting the Right Type of Catalytic Converter for Your Car

The first step in welding a catalytic converter is to select the right type of converter for your car. Catalytic converters are available either as universal fitment or direct-fit. A universal fitment converter is a more affordable option, but it may require modifications to fit your vehicle correctly. On the other hand, a direct-fit converter is designed to fit perfectly on your car's exhaust system, making the installation process more straightforward.

Before planning for a catalytic converter replacement, check which converter unit your car requires. A direct-fit converter simply requires removing your old unit by unbolting the flanges and bolting in a new unit. This is an easy and straightforward process that you can handle with the right tools.

Understanding The Use Case: Welding vs Brazing

When it comes to welding a catalytic converter, you have two primary techniques to choose from: welding and brazing. In the welding technique, the metal is joined by melting the base-metal and causing fusion, while in the brazing technique, the metal is joined by melting and flowing a filler metal into the joint.

Bronze welding method is considered an excellent alternative for welding coated (e.g., galvanized) thin sheet steels. It is also a perfect choice for welding a catalytic converter. The bronze welding method involves heating the area to be welded with a welding torch and adding the bronze welding material into the area to form the joint. This method works well for welding exhaust systems because it does not require extreme heat, which could potentially damage the catalytic converter.

How to Weld a Catalytic Converter: Step by Step

Step 1: Open the Older Catalytic Converter

Unbolt the whole exhaust system, detach the muffler, attach the new converter, and then re-bolt the system to replace this component of exhaust equipment. Alternatively, you may cut the by any cutting device the old converter and weld a new converter in its place using an appropriate welding process.

Step 2: Choose the Correct Catalytic Converter

Catalytic converters are often offered in direct-fit forms. Verify which converter gear your automobile requires before arranging a replacement. A direct-fit converter entails merely unbolting the bolts on your old converter and putting in a new one.

Cutting off the old converter from the exhaust system and welding in the new one is required for a catalytic converter replacement.

Step 3: Choose the Correct Technique for Welding

Although you may weld the catalytic using stick, MIG, flux, or TIG welding.  Although exhaust pipes are comprised of light metals, TIG or MIG welding is usually the chosen procedure. Begin welding the new converter to the existing tubing first, with safety goggles and gloves on, to keep the parts together.

Then start the rest of the welding. To avoid any exhaust leakage, it is critical to maintain uniformity when welding.

Ensure the flame is steady and press along the pace, making sure your arm is well supported and that there is enough area to weld uniformly with the joint.

Step 4: Ensure To Keep the Surface Of Welding Clean

To extract the corroded bolts and nuts, you may wish to apply penetrating converter lubricants. If you're thinking of doing TIG or MIG welding, make sure the core surface is dry and tidy of oils, corrosion, paint, or dirt.

Prior to welding the new catalytic converter to the exhaust system, wipe the tubing with acetone and a metal brush to eliminate oils.

Step 5: Ensure that There Aren’t any Weld Defects

After you've finished welding your catalytic converter in this exhaust system, take a look at the welds and see if there are any problems. In a butt weld, a lack of complete immersion might lead to a poor weld with low resistance, causing it to break early.

Your weld may fail if the welding velocity is high and the current flowing is too low, increasing the risks of an emission leak. Likewise, excessive current and speed can cause undercut and weaken the weld.

Step 6: Look for any Leaks

Following the visual examination, you should examine the exhaust pipe for any leakage. To detect air leaks, start the engine and listen for any creaking or whistling noises around the newly welded catalytic converter. Seal the leaks using cold-weld epoxy.

Final Note

The catalytic converter in your automobile is a critical component of the exhaust system which avoids hazardous emissions. You should get your catalytic converter tested and changed if you detect an exhaust pipe leakage or a grinding noise from your exhaust pipe.

You can weld your catalytic converter on your own at home. We described all the steps to do it ideally even if you’re a beginner.

Caution: It is not recommended to weld a catalytic converter as it can damage the internal components and reduce its effectiveness in reducing emissions. If your catalytic converter is damaged, it should be replaced with a new one. If you need to connect a new catalytic converter to your vehicle's exhaust system, it is recommended to use appropriate clamps and gaskets instead of welding.

Last Updated on 9 months by Richard Boyer

  • March 5, 2023
Richard Boyer

Richard Boyer has been a professional welder for over 27 years of his life, and now he is a trainer and blogger providing critical information to anyone interested in welding. He is helping out both hobbyists, novice and professional welders to learn newer and better techniques. Read more about me

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