Bundy tube, sometimes called Bundy pipe, is type of double-walled low-carbon steel tube manufactured by rolling a copper-coated steel strip through 720 degrees and resistance brazing the overlapped seam in a process called Bundywelding.
The Bundy Tubing Company, started in the US, was bought in the 1980s by what is now the British company TI Automotive.
A 1969 study by the Society of Automotive Engineers (SAE) recommended the replacement of Bundy tube with 90-10 copper-nickel alloy UNS C70600 (Kunifer pipe) because of corrosion concerns. Kunifer pipe has since been adopted by European automakers Volvo, Rolls-Royce, Lotus Cars, Aston-Martin, Porsche, and Audi. Bundy tube still retains the advantage of higher rigidity, which means less volume expansion under pressure.
- A.G. Imgram and D.K. Miner, Paper 690530, Mid-Year Meeting, May 1969
- "Copper-Nickel Automotive Vehicle Brake Tubing". Copper Development Association. Retrieved September 9, 2006.