A magnetic flowmeter includes a pipe with a non-conductive PTFE liner, magnetic coils to generate a magnetic field, and electrodes in contact with the fluid on opposite sides of the pipe. The electrodes comprise conductive PTFE patch electrodes bonded to the non-conductive PTFE liner so that an inner end of each patch electrode is exposed to fluid flowing through the interior pipe and an outer end of each patch electrode is aligned with an electrode hole in the pipe.