A muffler usually comprises two housing parts, namely two half-shells, which are joined with a seal being interposed therebetween. Such a seal must withstand high temperatures and compensate for unevenness at the sealing faces as well as withstand vibrations and gas pulsations of the muffler.
Experience has shown that the silicon seals or fiber seals normally used do not withstand the high temperatures which can be approximately 500.degree. C. so that considerable leakage can develop even after a short operating time. The arrangement of copper seals is likewise not satisfactory since warpage occurring because of high temperatures can lead to leakage and mechanical wear occurs because of unavoidable relative movements between the housing parts produced by vibration.