My Dream Project: Header Fabrication Begins

Some of you may have figured out by now that nothing on the "Black Hole" is purchased and just installed as purchased. Almost everything on a high end race car has to be fabricated and is a "One Off" custom piece.

Now that the engine mounts are fabricated and the body is temporarily installed, I am going to start fabricating the exhaust headers. This process starts with bare exhaust flanges and a box of 2 1/2 inch stainless steel tubing (some curved pieces and some straight pieces). Each header tube has to be hand formed (Like a blacksmith would do) on the header flange end to fit the shape of the exhaust port. Once the shape of the exhaust port is formed, the tube has to be out at the perfect angle so that the tubes exit in the proper place in the body of the car. Both the downward angle and the back sweep has to be right. It is easier said than done to get them exactly right and it is a very time consuming process. The gaps between the pieces of tubing have to be perfect so that they can be welded together to make a strong joint.

Once the tubes are all cut, they must be tack welded together and test fitted on the car. If a piece does not fit correctly, it has to be cut apart and refitted. Once everything fits correctly, the tubes have to be welded together permanently. The welding process that is used to weld stainless is called TIG (Tungsten Inert Gas) Welding. The process uses a tungsten electrode that melts the base metal while you feed filler rod into the molten puddle to weld the pieces together. Because molten stainless steel reacts with the oxygen in the air, a inert shield gas (pure Argon) is used to displace the oxygen and protect the molten puddle.

The TIG welding process is somewhat of an art form because it requires a coordinated effort of holding the electrode very close the the metal (without letting it touch), controlling how much electricity flows to the electrode (to melt the metal) with one of your feet (using a foot pedal), and feeding filler material with your other hand as you move the electrode around the part being welded.

Practice is the only way you can get proficient at TIG welding.

Here are the first two pieces that I have hand formed and cut them to the correct angles. Still a long way to go but it is very rewarding once you get the headers done.