Copper sounds like a possible alternative to stainless steel. It's readily available from plumbing stores, it comes in standard diameters, and it's malleable.
Its melting point and spalling temperature are close together at about 1030 deg C. If you need more airflow than provided by the diameter from one pipe, just add another in parallel.
Why not plain old steel or iron? I doubt the extra heat conductivity makes a big difference. (As it needs to transfer the heat to the air.) Okay, bending it requires some force, but it is readily avaible as well.
Location: Wellington, New Zealand
posted 2 weeks ago
For me the price of copper is 1/3 the price of stainless steel.