Sone304

Low-grade fiberglass packing burns out in months, causing the sone rating to climb as the exhaust gets louder. Premium Sone304 systems use stainless steel wool wrapped with basalt or ceramic fiber, lasting 5+ years.

Since "sone304" is not a real grade, you will not find it in a catalog. To avoid purchasing the wrong alloy, follow this procurement checklist: sone304

  • Specify the finish: Do you need 2B (smooth, reflective), BA (bright annealed), or No.1 (hot rolled, dull)?
  • Insist on a PMI test on delivery. Handheld XRF analyzers can confirm chromium and nickel levels in seconds.
  • Avoid "equivalents" from unknown mills unless you trust their quality control system.

    • A common myth is that all stainless steel is non-magnetic. SUS304 (Sone304) in the annealed state is mostly non-magnetic. Low-grade fiberglass packing burns out in months, causing

    However, after cold working (bending, rolling, drawing), it becomes slightly magnetic. This is due to the transformation of some austenite to martensite. Specify the finish: Do you need 2B (smooth,

    Do not use a magnet to reject "Sone304" material. A slightly magnetic response is normal for heavily worked 304. If it is strongly magnetic, it is likely 430 or 201.

    Never use mild steel filler on "Sone304"; it will cause galvanic corrosion at the weld.

    While Sone304 works on any car with a 304 exhaust, certain platforms respond exceptionally well: